DV Power RMO10T Manual 

& T A P C H A N G E R T E S T S E T Manual IBEKO POWER AB

2 Safety Instructions.................................................................................................................3 3 Designated Use.....................................................................................................................4 4 Functionality..........................................................................................................................4 5 Description ............................................................................................................................7 6 Getting Started......................................................................................................................9 7 RMOWin-T2M Software......................................................................................................18 8 Error Messages...................................................................................................................29 9 Technical Data ....................................................................................................................32 10 Accessories.........................................................................................................................33 Manufacturer Contact Information..............................................................................................33 Manual Version: RMO10T. MV. RT1-6.02 This Manual refers to the firmware version RT1-6.02 IBEKO POWER AB 2009 This Manual is a publication of IBEKO POWER AB, 181 33 Lidingö, Sweden. All rights including translation reserved. Reproduction of any kind, e.g., photocopying, microfilming or storage in electronic data processing systems, requires the explicit consent of IBEKO POWER AB. Reprinting, wholly or in part, is not permitted. This Manual represents the technical status at the time of printing. The product information, specifications, and all technical data contained within this Manual are not contractually binding. IBEKO POWER AB reserves the right to make changes at any time to the technology and/or configuration without announcement. IBEKO POWER AB is not to be held liable for statements and declarations given in this Manual. The user is responsible for every application described in this Manual and its results. IBEKO POWER AB explicitly exonerates itself from all liability for mistakes in this Manual. IBEKO POWER AB translates this Manual from its source language English into a number of other languages. Any translation of this Manual is done for local requirements, and in the event of a dispute between the English and any non-English versions, the English version of this Manual shall govern.

1 Introduction This Manual contains helpful instructions on how to use RMO10T in a safe, proper and efficient way. Following these instructions can help you avoid dangerous situations, repair costs and other miss happenings due to incorrect operation. Furthermore it ensures the reliability and life cycle of your RMO10T. RMO10T must be used in observance of all existing safety requirements and regulations from national/local standards for accident prevention and environmental protection. Reading the RMO10T Manual alone does not exempt the user from the duty of complying with all national and international safety regulations relevant for working with RMO10T. 2 Safety Instructions Before operating RMO10T, please read carefully the following safety instructions. It is not recommended that the RMO10T is used (or even turned on) without the understanding of this Manual. RMO10T should only be operated by trained and authorized personnel. Rules for Use • RMO10T should only be used when in a technically fit condition. Its use should be in accordance with the safety regulations for the actual working site and application. Always be aware of the dangers of high voltages and currents associated with this equipment and its environment. Pay attention to the information provided in the Manual. • RMO10T is intended exclusively for the application areas specified in ”Designated Use”. The manufacturer and distributors are not liable for damage resulting from wrong usage. The user alone assumes all responsibility and risk. • The instructions provided in this Manual are considered part of the rules governing proper usage. • Do not open RMO10T. All service and maintenance work must be performed by qualified personnel. Orderly Practices and Procedures • The Manual should always be available on the site where the RMO10T is used. • Before using RMO10T, all personnel (even personnel who only occasionally, or less frequently, work with RMO10T) assigned to RMO10T should read the operations Manual. • Do not undertake any modifications, extensions, or adaptations to the RMO10T. • Use RMO10T in conjunction with original accessories only. • Use both RMO10T and its original accessories for its designated use only. Cleaning To clean RMO10T, use a cloth dampened with isopropanol alcohol or water. Operator Qualifications • Testing with RMO10T should only be carried out by authorized and qualified personnel. • Personnel receiving training, instruction, direction or education on the RMO10T should remain under the constant supervision of an experienced operator while working with the test set and the test object.

Safe Operation Procedures • Hazardous voltages of up to 400V can occur inside RMO10T. Therefore, it is not permitted to open RMO10T. • Do not insert objects (e.g., screwdrivers, etc.) into the ventilation slots. • Before putting RMO10T into operation, check the test set for any visible damage. • Do not operate RMO10T under wet or moist conditions (condensation). • Do not operate RMO10T when explosive gas or vapors are present. • The serial interface of RMO10T should only have external devices connected that meet the requirements for SELV equipment according to EN 60950 or IEC 60950. • When setting up RMO10T, make sure that the air slots of the test set remain unobstructed. • If RMO10T is opened by the customer, all guarantees are invalidated. • If RMO10T seems to be functioning improperly, please contact the IBEKO POWER AB (refer to section ”Manufacturer Contact Information”) after first checking the section Error Messages. • Do not use RMO10T without the extra protective ground cables for RMO10T and winding connection. Always establish this connection as the first one before you do any other connections, and separate this connection as the very last one. • Never open the measuring circuit while current flows as dangerous high voltage may occur. This is indicated by the red discharge LED and the beeper. Power Supply • Supply RMO10T only from a power outlet that is equipped with protective ground. • Instead of supplying RMO10T from phase – neutral (L1-N, A-N), it may also be supplied from phase to phase (e.g., L1-L2; A-B). However, the voltage must not exceed 240 V AC, please refer to the section Technical Data. 3 Designated Use The Winding Ohmmeter RMO10T is designed for measuring resistances of inductive test objects used in the electric power industry or similar industries. It is employed for resistance measurement during manufacturing, commissioning and testing of: � transformers, � on-load tap changers, � generators and electrical motors, � high current busbar joints, � cable splices. Any other use of the RMO10T than the ones mentioned above is to be considered improper and will not only invalidate all customer warranty claims but also exempt the manufacturer from its liability for repair or exchange. 4 Functionality 4.1 Current Test The RMO10T generates a filtered (true) DC current. RMO10T test set can measure the winding resistance of any transformer; small or very large, single or three phase, star, delta or zig-zag connected. There are two independent measuring channels which can be used to simultaneously measure resistance of up to two windings at the same time. Choose the test current so that the maximum value is obtained for the expected resistance (refer to section 6.1).

The inductance value of a transformer depends on the current injected in the windings. When the transformer is saturated the inductance is minimized. A transformer is normally designed to reach saturation when the current is 1,2 times the peak value of the no-load current. The no-load current is normally in the range of 0,2% to 5% of the nominal winding current. When measuring the DC resistance, the test current should be at least 1,2 times the no-load current of the transformer. This is to ensure that the transformer core is saturated. Note also that the test current is NOT to exceed approximately 10% to 15% of the nominal winding current. Note: The Voltage sense measuring channels are automatically selected connecting measuring cables to those channels. At the start of each test a check of cable continuity is done. In case of open circuit, an alarm is activated, and the error message is shown on the display. The test is started by pressing the OMEGA button. The RMO10T injects current with a voltage as high as 60V. This ensures the test to be as short as possible and that the desired test current is reached faster. When the current is stabilized, RMO10T measures the resistance of the test object. The test result is displayed as R=U/I. During the testing period, a new result is shown on the display approximately each second. Tests could be finished or interrupted two ways: - Pushing the STOP button, - Automatically, after the selected time has expired. In both cases, upon completion of the test, a measured value of the resistance is recorded to pre- selected internal memory location. Each time the Ω button is pushed, results of the resistance and the test current value are stored into the internal memory of RMO10T, and memory location changes to the next one. Minimum measurement time is 30 seconds. By pushing the STOP button test could be completed at any time. When the STOP button is pushed, the last measured result will remain saved in the internal memory. After the selected test time has expired, the last result remains saved at selected memory location. Note: Using RMOWin-T2M the results could be stored to a PC, where reading interval of results is adjustable. Results will be shown in a table in Excel format with an option to perform additional edit and graphic presentation. Using RMOWin-T2M after the test in order to transfer the results from selected internal memory location to a PC, will allow transfer of the last test result only. When the measurement is complete, RMO10T starts discharging the energy from the inductance. During current discharging, the red discharge LED is lit and the buzzer is ON. Discharge is complete when the discharge LED and the buzzer are OFF. Both, injection of current and discharging energy from the inductance is fully automatically regulated. An intrinsically safe discharge circuit, with indicator, dissipates the stored magnetic energy rapidly after the test. Cooling of RMO10T is supported by a built-in fan that is automatically activated when the device is turned on.

4.2 Tap Changer Test The TapC menu offers a user friendly way of measuring winding resistance in tap changers. RMO10T test set measures the winding resistance of individual taps of a power transformer’s tap changer, and checks whether the On-Load Tap Changer (OLTC) switches without a discontinuity. In the moment the tap is changed from tap to tap, the device detects the sudden, very short drop of the current flow. A properly working tap changer differs from a malfunctioning one in a discontinuity during the change, by the magnitude of the current ripple value. An interruption will result in a much higher ripple value than a properly functioning tap changer. Note: In TapC menu only Ch:1 is the active channel. At the start of the test a check of cable continuity is performed. In case of disconnection, an alarm is activated, and the error message is shown on the display. Note: Using RMOWin-T2M in TapC menu the results could be stored to a PC. By pushing the Ω buton a resistance result and current ripple value are stored in internal memory location, and the memory location is automatically increased by one.

Ω button Press to start a test Press to measure the resistance current value. Press to measure the resistance value in TapC mode Green LED • Lights continuously when RMO10T is turned on. • Flashes when a test can be started. • Flashes alternately with the red LED during a test. Red LED • Lights continuously in case of operational error. • Lights continuously during discharging process. • Flashes alternately with the green LED during the Current test. • Flashes shortly during resistance measurement in the TapC test. • Flashes alternately with the green LED during the TapC test. Red LED - Discharge • The red LED just above the red output connector remains lit until the accumulated energy of the measured object is reduced to a harmless level CAUTION Within the period when the discharge LED lights it is prohibited to disconnect measuring cables. The discharge diode could not be switched off by the STOP button. Display UP/DOWN buttons to select a menu and set test parameters LEFT/RIGHT buttons to navigate in the active menu ENTER button to confirm the defined test parameters, Language, and Time and Date STOP button to stop a test, to acknowledge the alarm buzzer and return to the Curr menu

5.3 Setting RMO10T’s Language To set RMO10T’s language, use the LEFT button, and then the UP buttons to select the Language menu. Move the cursor to the bottom line using the LEFT/RIGHT buttons, and select the language with the UP/DOWN buttons. Pressing ENTER to confirm, returns you to the Curr menu. Pressing STOP to cancel, returns you to the Curr menu. 5.4 Setting RMO10T’s Time and Date To set RMO10T’s internal time and date, use the LEFT button, and then the UP button to select the Time menu. Move the cursor to the position of your choice using the LEFT/RIGHT buttons, and change the value with the UP/DOWN buttons. Pressing ENTER to confirm, returns you to the Curr menu. Pressing STOP to cancel, returns you to the Curr menu. Earth/ground connector. For protection against parasitic currents or voltages, always connect RMO10T earth/ground connector to protective ground (PE). Use only the original cable. For safety reasons, always establish this connection as the first one before you do any other connections, and separate this connection as the very last one. Ventilation Figure 5-1: The Language menu Figure 5-2: The Time menu showing RMO10T’s internal time and date Connector for mains power supply Power switch I In this position, RMO10T is connected to the mains power supply. 0 In this position, RMO10T is separated from the mains power supply with both poles.

6 Getting Started 6.1 Current test Connecting a Test Object to the RMO10T Before you connect a test object to RMO10T, make sure that: • The test object is disconnected or separated from its circuit in accordance with the national safety regulations and is properly grounded to protective earth. • RMO10T itself is properly grounded. To do so, connect the grounding screw on the back of RMO10T’s to PE using a grounding cable. • One end of measured windings is properly grounded. • See example of a two channel setup in the figure below (6-1). C A U T I O N � FOR SAFETY REASONS, ALWAYS ESTABLISH A CONNECTION OF THE DEVICE WITH TEST OBJECT IN THE WAY AS DESCRIBED IN THE FIGURE 6-1. � DO NOT CONNECT MEASURING CABLES AFTER TEST STARTS. � DO NOT DISCONNECT ANY LEADS BEFORE THE LED DISCHARGE AND THE BUZZER ARE OFF. The Figure 6-2 shows simultaneous testing of both windings (high and low) on a single-phase transformer. In such a way, it is possible to speed up the measurement when two channels are used to test both windings of the transformer. When performing a two channel measurement; connect the Current connection cable as in the example below (Figure 6-2.) and outside the Sense leads. Figure 6-1: Connecting a test object to RMO10T With RMO10T turned off, connect RMO10T to the test object in such a way that the measuring cables from the "Voltage Sense" sockets are attached as close as possible to RX, and in between the current feeding cables. That way, resistance of both cables and clamps is almost completely excluded from the resistance measurement. Pay attention to polarity while connecting measuring cables. To maximize accuracy and measurement repeatability; make sure that all clamps have a good connection to the test object and avoid any connection between Sense and Current clamps.

Testing of a Delta-delta winding resistance is usually a very time consuming procedure. This is because the two windings resemble two closed loop inductors. When energy is brought into the inductors, this energy (in the form of D.C. current) continually circulates within each winding. A method to quickly test this configuration requires that both the high side and low side are connected in series with the Winding Ohmmeter. By having these two windings in opposing polarity, the internal circulating currents settle very quickly to obtain a balance, and discharge with the same speed. Even if only one side of the transformer needs to be tested, connecting both high and low windings in series will speed up the test considerably. On/Off Connect the earth/ground lead first before doing any connections to the test object. Connect the mains lead to a mains outlet 100 V – 240 V AC and turn on RMO10T with the power switch on the back of the test set. The first shown on the display is the name of the product followed by the instrument model type and the internal firmware version. Figure 6-2: Connecting a test object to RMO10T Figure 6-3: Connecting a test object to RMO10T

Setting the Measurement Parameters Directly after the first display RMO10T automatically changes to the Curr menu and the green LED lights up. Before a test can be started, the following needs to be defined in the Curr menu: � Test current; the following values can be chosen: 5 mA, 10 mA, 50 mA, 100 mA, 500 mA, 1A, 2A, 5A, 10A. � Memory position, 00-99 � Test duration time can be set between 5 minutes and 60 minutes depending on test current, see table under “Measurement parameters” (section 6.5). In the Curr menu, define a test current for the test (here 10A). To do so, set the value of your choice by means of the UP/DOWN buttons. Define the memory position (here m:23). Using button RIGHT move the cursor to the memory location position, and using UP/DOWN select desired memory position to which obtained results would be saved. Once the test is completed (either due to time expiration or when pushing the STOP button) the last measured result will remain registered in RMO10T, and the memory position is automatically switched over to the next memory position. The result can be recalled later by selecting that particular position number. Using RIGHT button move the cursor to the test duration position, and using UP/DOWN buttons select desired value. Measuring with RMO10T Before a test can be started, test current, memory position and the test duration time need to be defined using the Curr menu. Once these parameters are defined, press ENTER to change to the Ready state. The Ready state displays the selected test current and its duration is defined. If one of these values has to be changed, press STOP to return to the Curr menu. The flashing green LED indicates that RMO10T is now ready to start the test. Press the OMEGA button to run a test. At the start of the test, a cable connection check is done. In case of e.g. a disconnection, an alarm is activated and the error message is shown on the display. During the test, both the green and the red LEDs flash alternately and the buzzer beeps. When the current is stabilized, RMO10T starts the measurement of the test object resistance. The display shows test current (here 9,98A) and the effective value of the measured resistance (here 789,1mΩ on channel 1 and 788,9mΩ on channel 2). The time remained until the end of test procedure is also shown on the display (here 12s). Test could be completed in two ways: - Pushing the STOP button, - Automatically after the selected time has expired. Figure 6-4: The Curr menu Test current Memory position Test duration time Menu name Figure 6-5: The Ready state before the test Figure 6-6: The Curr menu during the test Time

When the test is finished either because selected time has expired or the STOP button is pressed, the RMO10T switches to the Res menu and starts current discharging process. During current discharging, the discharging LED lights and the alarm beeps. Discharge is completed when LED discharge and the buzzer are OFF. Also, during that period “Discharging” message is shown on the display. During discharging process it is not possible to start another measurement. Once the test is completed the last measured result will remain registered at a selected memory location (00-99 memory locations). Discharge Current The voltage at the RMO10T output generation is immediately stopped, but current still flows, because of the inductivity of test objects. Because of the enormous amount of energy that can be stored in a magnetic field, precautions should be taken before disconnecting the test leads from the transformer that is under test. Never remove the leads during the testing process and always allow enough time for the transformer being tested to completely discharge. Large transformers can require several minutes to discharge. C A U T I O N � DO NOT DISCONNECT LEADS BEFORE “DISCHARGING” MESSAGE IS DISAPPEARED FROM THE DISPLAY. Note: Using RMOWin-T2M the results could be stored to a PC, where reading interval results is adjustable. Results will be shown in a table in Excel format with an option to perform additional edit and graphic presentation. Using RMOWin-T2M after the test in order to transfer the results from selected internal memory location to a PC will allow transfer of the last test result only. Measurement parameters Typical accuracy given below is valid if the maximum possible current is used. Range Test Current Nominal Resistance Full Range Display Resolution 1 10A 1mΩ 999,9µΩ 0,1µΩ 2 10A 10mΩ 9,999mΩ 1µΩ 3 10A 100mΩ 99,99mΩ 10µΩ 4 10A 250mΩ 250,0mΩ 0,1mΩ 5 10A 750mΩ 750,0mΩ 0,1mΩ 6 10A 1,25Ω 1,250Ω 1mΩ 7 10A 2,5Ω 2,500Ω 1mΩ 8 5A 5Ω 5,000mΩ 1mΩ 9 2A 10Ω 9,999Ω 1mΩ 10 1A 15Ω 15,00Ω 10mΩ 11 500mA 25Ω 25,00Ω 10mΩ 12 100mA 100Ω 99,99Ω 10mΩ 13 50mA 200Ω 199,9Ω 0,1Ω 14 10mA 1kΩ 999,9Ω 0,1Ω 15 5mA 2kΩ 2000Ω 1Ω The highest resolution of the reading is always displayed; resistance range selection is performed automatically and therefore is not necessary to be set by the operator. Figure 6-7: The Res menu showing the test results

Accuracy Typical accuracy of RMO10T is ±(0,2% rdg + 0,2% FS). This accuracy is valid if the maximum possible current is used. Always try to use as high current as possible, but to avoid the risk of heating the winding, it is recommended not to exceed from 10 % to 15 % of the nominal current of transformer. It is important to get a good connection between clamps and the connecting point on the test object to achieve stable and accurate test results. Guaranteed accuracy is ±(0,4% rdg + 0,4% FS). Viewing the Test Results Once a test is finished, RMO10T automatically changes to the Res menu to display the test results. 6.2 Tap Changer test Using RMO10T’s Tap Changer (TapC) menu the winding resistance of individual taps of a power transformer’s tap changer can be measured. Also it can be used to control the transformer tap changer. This is a user friendly way of winding resistance measurement and tap changer control, since automatic measurement is possible with no need to remove the current between each tap change. During switching the inputs of the instrument are protected to avoid damage that could occur should a tap changer prove to be faulty during testing. From the current outputs, RMO10T injects a constant current into the power transformer. From this current value and the voltage measured, the winding resistance is calculated. A discontinuity caused by a defective tap changer results in a comparatively high measured values of current ripple. Setting the Measurement Parameters Turn on RMO10T with the power switch on the back of the test set. The display shows the Curr menu and the green LED lights up. Press button LEFT and using UP button go to the TapC menu. In the TapC menu, define a test current for the test (here 10A). The following values can be chosen: 1A, 2A, 5A, 10A. Figure 6-8: The Res menu showing the test results Test current Memory position that holds the results Measured resistances of the test objects Figure 6-9: Connecting a test object to RMO10T and RMOWin-T2M Figure 6-10: The TapC menu Test current Memory position Time Menu name Active channel

To do so, set the value of your choice by means of the UP/DOWN buttons. In the TapC menu of RMO10T, current output value is rated continuously at 10A or less. Define the memory position (here m:87). Using button RIGHT move the cursor to the memory location position, then using UP/DOWN select desired memory position to which obtained results would be saved. By pushing the Ω button, resistance and current ripple measured results will remain registered in internal memory of RMO10T, and the memory position is automatically switched over to the next memory position. These results can be recalled later by selecting that position number. Note: Only Ch:1 (left channel) is active channel. Measuring with RMO10T Before a test can be started, test current and memory position need to be defined using the TapC menu. Once these parameters are defined, press ENTER to change to the Ready state. The Ready state displays the selected test current and memory location. If one of these values has to be changed, press STOP to return to the TapC menu. The flashing green LED indicates that RMO10T is now ready to start the test. Press the OMEGA button to run a test. At the start of the test, a cable connection check is done. In case of e.g. a disconnection, an alarm is activated and the error message is shown on the display During the period of current stabilization, both the green and the red LEDs flash alternately, buzzer beeps and message “WAIT” is shown on display. When the current is stabilized, the device shows test current (here 9,97A) and the value of the measured resistance (here 704,2mΩ). During the resistance measurement the red LED flashes shortly and beeper sound is speeded up. At the moment the resistance result is stable press the OMEGA button to save the result. The memory position is automatically switched over to the next memory position and device is ready to record the current ripple. Change the Tap Changer position to the next tap by pushing the "Up" or "Down" button of the tap changer control. Because the resistance is changed, current will be unstable and RMO10T will sample and hold the largest measured current ripple that occurred in the actual measuring cycle. It is indicated as Δ (%) with reference to the test current. The display shows the value of the test current in new tap position (here 9,93A), and the value of the current ripple occurred during the change from previous position to the new one (here 4,6%). At the moment the test current shown on the display is stable, the RMO10T shows the resistance value in new tap position (here 719,3mΩ). At the moment the test resistance is stable press the OMEGA button to save the resistance and the ripple in the new position of Tap Changer. Figure 6-11: The Ready state before the test Figure 6-13: The TapC menu during the resistance test Figure 6-12: The TapC menu during current stabilization Figure 6-14: The TapC menu, memory position is increased for one

Repeat this procedure as often as needed until the results for RIPPLE (Δ) and RESISTANCE (R) are obtained for all Tap Changer positions. Test is completed pushing the STOP button. The voltage at the RMO10T output generation is immediately stopped, but current still flows, because of the inductivity of test objects. When measurement is completed (after pressing the STOP button) RMO10T switches to the TapC menu and starts current discharging. During the current discharging process, the discharging LED lights and alarms beeps. Discharge is completed when LED discharge and the buzzer are OFF. Also, during that period “Discharging” message is shown on the display. During discharging process it is not possible to start another measurement. A properly working tap changer differs from malfunctioning one in a current discontinuity during the tap change, by the magnitude of the current ripple value. A discontinuity will result in much higher current ripple value (99 % or 100 %) than a properly functioning tap changer. Note: Current ripple value depends on the construction of the tap changer. It is recommended to compare current ripple values between each other got on one transformer. Also, it is recommended to compare current ripple results on one transformer with results from some previous test in order to follow conditions of that tap changer. Figure 6-16 shows indication about possible tap changer bad conditions during the change from tap to tap. If current circuit is opened during the change from tap to tap, message „Discontinuity“ will be shown on the display, red LED will light and buzzer will beep continuously. Discharging process starts. Discharge Current The voltage at the RMO10T output generation is immediately stopped, but current still flows, because of the inductivity of test objects. Because of the enormous amount of energy that can be stored in a magnetic field, precautions should be taken before disconnecting the test leads from the transformer that is under test. Never remove the leads during the testing process and always allow enough time for the transformer being tested to completely discharge. Large transformers can require several minutes to discharge. C A U T I O N � DO NOT DISCONNECT LEADS BEFORE “DISCHARGING” MESSAGE IS DISAPPEARED FROM THE DISPLAY. Note: Using RMOWin-T2M the results could be stored to a PC, where reading interval results is adjustable. Results will be shown in a table in Excel format with an option to perform additional edit and graphic presentation. Figure 6-15: The TapC menu during discharging Figure 6-16: The TapC menu showing much higher current ripple value Figure 6-17: Message "Discontinuity"

Using RMOWin-T2M after the test in order to transfer the results from selected internal memory location to a PC will allow transfer of the last test result only. Using RMOWin-T2M software it is possible to draw a graph which represent dynamic resistance during the change from tap to tap (refer to section 7.4 on page 20). 6.3 Viewing Results of Previous Tests RMO10T stores up to 100 test results. They can be viewed using the Mem menu at memory positions from 0 to 99. Go to Mem menu using LEFT, and then pressing the DOWN button. Selecting a memory position on the Mem menu displays: • the current fed into the test object, • the memory position of these results, • the test object’s measured resistance R1 (left channel) or R2 (right channel), • the test object’s measured results R (resistance) or Δ (current ripple), • the date or the time, of this particular test. To view the measured resistance R2 rather than the resistance R1, position the cursor on the first letter of the Mem menu (here M), and use the LEFT button to toggle between resistance R1 and R2 or between R and Δ. To view the creation date of the test rather than the time, position the cursor on the latest number of the memory position (here 3), and use the RIGHT button to toggle between date and time. 6.4 Deleting Results of Previous Tests In the Mem menu, press ENTER. Press ENTER once more to delete all saved measurements from the memory positions. Press STOP to leave the Mem menu without deleting any measurements. Figure 6-18: The Mem menu showing the previously saved test results measured in Curr mode saved in memory position 23 Figure 6-21: The Mem menu showing an option to delete all saved measurements from the memory positions Figure 6-19: The Mem menu showing the previously saved test results measured in TapC mode saved in memory position 93

6.5 Printing the Test Results RMO10T stores up to 100 test results. They can be printed using the Print menu at memory positions 0 ... 99. Go to Print menu using LEFT and then UP button. Selecting first and last memory position and press ENTER button. The results that are located in the range between these memory locations, including the chosen memory locations, will be printed. Note: It is not possible to print test results using the built-in printer from RMOWin-T4Software. If printing is attempted the device will be blocked and a reset of the device is necessary. Look of a RMO10T Test Report are given at figures below: 6.6 Duty Cycles During tests, RMO10T generates a high DC current that heats up the test set. To prevent RMO10T from overheating, certain duty cycles apply depending on the test current used. Cooling time between two measurements is proportional to test duration time. A built-in control prevents skipping these cooling times. If you try to start a test within the cooling period, the display shows "Wait" and a timer counting down. After the cooling period has passed, start a new test using the set test parameters by pressing the OMEGA button. C u r r e n t T e s t Test current (A) Maximal test duration time (min) Cooling time for maximal test duration time (min) 5mA, 10mA, 50mA,100mA, 500mA, 1A, 2A, 5A, 10A 60 0 Figure 6-22: The Print menu showing first and last memory position and Date and Time of printing Table 6-23: Cooling time between current tests

7 RMOWin-T2M Software RMOWin-T2M is a Windows program for working with Winding Ohmmeters RMO10T. It enables the two- way communication RMO10T to a PC over the USB. Microsoft Office Excel program must be installed on the PC. RMOWin-T2M supports the following functions: - Controlling and starting RMO10T when the tests are performed from the PC; the results could be stored to PC; results reading interval is adjustable, - Transfer of test parameters from the local RMO10T memory to the PC with the possibility of writing the notes on objects being measured, and appropriate comments. Note: Using RMOWin-T2M software, a device RMO10T must be operated only from the RMOWin-T2M. Data transferred from RMO10T can be: - Displayed in the form of tables, - Downloaded as an Excel file. Every test reading parameter contains: - The memory location, - The date and the time of the test, - The real test-current, - The measured resistance values, - The measured voltage values, - The measured ripple values, - The name of the object (tested device) and the useful comments. 7.1 The minimum system requirements Processor : Recommended > 500MHz Memory : min 32 Mb Operating system : 95/98, NT, 2000, XP The hard disk space : > 10 Mb 7.2 RMOWin-W installation To install the RMOWin-T2M software do the following: - Insert the RMOWin-T2M installation CD into the CD-ROM drive, - Click on ”Start”, - Click on ”Run”, - Click on ”Browse”, - Select the CD-ROM drive, - Highlight the ”RMOWin-T2M.EXE”, - Click on ”Open”, - Click on ”OK”, - Follow the instructions displayed on the screen, - When the installation process has been finished - exit the program.

7.3 Starting RMOWin-T2M Connect the USB port of the RMO10T Winding Ohmmeter and the PC, using a serial cable. Turn RMO10T on. Start RMOWin-T2M: - Click on ”Start”, - Click on ”Programs”, - Click on ''RMOWin-T2M’’, or duble click at icon on the desktop. The look of the RMOWin-T2M main menu is shown in the following illustration. If the ”Communication” field displays the green led-diode and the sign ”ON” is lit, the communication has been established and the program is ready to be used. Now the RMO10T can be controlled from the PC. Clicking with the mouse on any key of the keyboard has the same effect as pressing the keys on the RMO10T. In case that the green led diode is not lit in the “Communication” window, i.e. the red led diode is lit, it is necessary to check the following: - Is the green led diode on the RMO10T lit? - Is the RMO10T signaling any error? - Is the serial cable connected tightly? It is strongly recommended to write the information in the columns ”Object”, ”Code” and ”Comments” for better systemization of the saved results. The new test moves previous test results down so the first line represents the last performed test. The way to measure the resistance is described in details in the RMO10T Manual. If a user wants to analyze these results later, it should be saved on the hard disk. The table is going to be saved as an Excel file, so it can be later used with all Excel functions.

7.4 Graphic function Using a PC together with RMO10T device in the Tap Changer mode it is possible to conclude about tap changer conditions analyzing a graph which represents dynamic resistance during tap changes. Figure above shows connections between a PC and RMO10T. After all connections are properly done and RMOWin-T2M is started, chose TapC menu by clicking with the mouse on the RMOWin-T2M buttons LEFT and then UP. Note: Using RMOWin-T2M software, a device RMO10T must be operated only from the RMOWin-T2M Note: Before the beginning of the test set tap changer in the first or the last tap changer position. Graphic function is available as on-line or off-line mode. Using on-line mode, test current value during the transition from tap to tap is shown on the graph. The on-line mode Graph control window shows information about current and next tap changer positions. This information is not shown in the off-line mode. In the off-line mode saved files containing graph data are opened. Graph control window contains options and commands to control graph display. Graph is displayed in separate window, where user can zoom in and zoom out interesting parts of the graph. Test current values are shown on the vertical axis, and tap transitions are shown on the horizontal axis. Two markers are available for measuring time difference, test current difference and current ripple between two positions on the graph. Also, in the on-line mode there is OMEGA button used to measure static resistance in the current tap changer position. This is not available in the off-line mode. After pressing ENTER button, fulfill dialog box Tap Changer Settings with all necessary information about the tap changer.

Press OMEGA button to start the test current. When the test current is stabilized press OMEGA button to measure resistance in the first tap changer position. Measured resistance value is saved in current memory location and memory location is automatically changed to the next position. After below message is appeared pres OK button. When the message “Change the tap position” is appeared on the main window, change the tap position. When the tap position is changed the graph with the test current during the change will be displayed. That graph represents dynamic resistance during the change from tap to tap. Press OMEGA button to measure resistance in the new tap changer position. It is possible to press OMEGA button either on the graph window or on the main window. Repeat this procedure until you get all results. The diagram should looks like at the figure below

It is possible to zoom in a part of the graph of the interest by holding down the Shift key and dragging the left mouse button around the required area. While dragging around the area, the dotted rectangle is shown around the selected area. First release the mouse button and then the Shift key, and the selected area is zoomed in. The same operation can be repeated on the zoomed area. To show complete graph double-click on the graph area. The graph can look like on the figure below. When the test is finished, press the STOP button. There will be message to save test results. Note: After the test is finished it is possible to recall the graph and analyze it.

7.5 Main Menu The illustration below depicts the main menu. File Open 1. In your RMOWin-T2M program, click File, and then click Open. 2. In the Look in list, click the drive, folder that contains the file you want to open. 3. In the folder list, locate and open the folder that contains the file. 4. Click the file which you want to open, and then click Open. Saved files containing graph data can be opened using the RMOWin-T2M File/Open command and selecting file.CSV to open Excel document, file.txt to open plain text file or file.tcp to open tap changer plot - graph from the "Files of type" select list in the opened dialog. After existing file.tcp is opened, all operations on the graph regarding zooming, using markers, etc. are the same as operations on the on- line graph mode. Save Save the table as an Excel file or a graph as a tcp file. Initially it is suggested to save in the working directory. Files containing graph data are saved by default in a custom format with file extension tcp (Tap Changer Plot). This file format can be opened by RMOWin-T2M software to analyze the graph in the off-line mode. Other possible file formats are CSV (Comma Separated Values) and TXT (plain text file). If the file is saved in other format than tcp, it is required to choose file type in the save dialog. Files saved in the CSV format can be opened using Microsoft Excel and formatted in the columns containing graph data. Selected data range can be plotted using Excel features. The TXT files can be imported to the other programs using import function. Note: Security features of Windows Vista may prevent saving data to default RMOWin-T2M working directory under Program Files directory. This is under condition that the User Account Control (UAC) option is enabled on user's computer. In this case the data is saved to Virtual Store directory, which is hidden and may prevent user to find saved files. If the UAC is enabled, it is suggested to save data in other directories under ownership of the user, like Documents or some other user created directory. If the UAC is disabled these restrictions are not in effect. Print Print the table or the graph. Exit Return to the main menu.

Download Data From RMO10T With this command the results from the internal RMO10T memory can be transferred to the PC. The transfer is possible only if the serial port RMO10T is connected, with the appropriate cable, to the PC and the green led diode ”Communication” is lit (ON). The results a user wants to transfer from the RMO10T memory to the PC can be selected according to following criterion: All All the test results are being transferred from the internal RMO10T memory to the PC. Date The results that are obtained on the chosen date are going to be transferred to the PC. Date from – up to After choosing this option, a new window appears. It provides a choice to select a time- interval when the measurement was done. The results obtained during the time period between the chosen dates, including the chosen dates, are going to be transferred to the PC. Memory from-up to It opens a new window that allows a choice of memory locations to be transferred to the PC. The results that are located in the range between these memory locations, including the chosen memory locations, will be transferred to the PC. The more detailed description on how to use the memory locations can be found in the RMO10T Manual.

Once the desired transfer criterion is selected it is recommended to write the name of the object (device) that was tested as well as comments (14 character max) that can be used in the future analysis of the results. These comments will be displayed in the table together with the results. Transfer When this key is pressed, the selected results are transferred from the internal RMO10T memory to the PC. Unless the user chooses some other option, all the results from the RMO10T memory will be transferred (the option All is a default). After pressing the command transfer, the graphical bar is being displayed showing a status of the transfer. Stop A user should press the “Stop” button if for whatever reason he wants to interrupt the transfer. After pressing this key all the choices are being erased and the user will return back to the main menu. The results table When the results are transferred to the PC, the table with the following layout will be displayed (see illustration): Current mode - Memory : the number of the memory location in the RMO10T where test results are located - Date : the date of the test - Time : the time of the test - Current : the real test current - Voltage 1 : the measured voltage on the channel 1 (Ch:1) - Resistance 1 : the measured resistance on the channel 1 (Ch:1) - Voltage 2 : the measured voltage on the channel 2 (Ch:2) - Resistance 2 : the measured resistance on the channel 2 (Ch:2) - Ripple : the results are zeros - Object : the name of the object - Code : the code of the tested object - Comments : comments Current from – to Selecting this option opens a new window, providing a selection of the currents that were used during the test. The choice of the current is made on the drop-down menu. The range of the values that are between and including the selected values of the current, are going to be transferred to the PC. Ripple from – to Selecting this option opens a new window, providing a selection of the current ripple that occurred during the test. The results of selected current ripple are going to be transferred to the PC.

Tap Changer mode All columns are the same except the following: - Resistance 1 : the measured resistance (R) - Ripple : the measured current ripple in percents - The results in other columns, which are not relevant to the Tap changer mode, are zeros. Tools Clear the table Erase all data from the main menu board. Tap changer Settings This option is used for setting parameters of the tap changer. RMOWin-T2M enables recording current values when changing the tap changer positions and plotting the recorded values. If this function is not needed, please check the option "Do not use graphing function". If this function is needed, leave it unchecked. Total taps: The number of tap positions, excluding nominal positions. This could also be interpreted as the last tap position number. Direction: It means the direction of changing the tap positions. Nominal positions: It means whether the tap changer has nominal positions or not. Nominal positions type: It is the type of nominal positions. Motor drive or manual cranking: means of changing the tap changer positions. Advanced Advanced settings for the tap changer graphic function. These settings are recommended for advanced users. Ripple detection: Setting for detecting the current change in percents, during the tap changer positions change. Steady state detection: Setting for detecting the current stabilization after the tap position changed. After the current stabilization, the current diagram is shown for the previous tap changer positions.

Options Working directory The selection of the working directory that is going to be the default one for opening and saving tables and files. Output format Define the file format of the saved table. Date format Define the date format that is going to be shown in the table with the results of the test. Interval Its purpose is selection of time interval for reading results from RMO10T to PC. At the expiration of this interval the last measured result from RMO10T to PC will be written, and this process will repeat at the expiration of the next period. Press function “Interval”. The window, as shown bellow, will be opened. Possible work ratings are “AUTO” and “MANUAL”. By selecting “AUTO” rating and time interval, the last measured result will be transferred from RMO10T to PC at the chosen time intervals. By selecting “MANUAL” rating, the last measured result will be transferred from RMO10T to PC each time when the button Ω is pressed.

Resistance compensation Resistance compensation is a feature that enables displaying resistance calculated to reference temperature. This feature is available when controlling RMO10T from the PC. Two new columns are displayed in the data table, denoting the calculated resistance values. When the measurement is performed for the first time the following dialog window is displayed. If resistance calculation is needed, it is necessary to choose answer “Yes” in the previous window. New window is displayed for setting required parameters. One of the parameters is Winding material. User can choose between Copper, Aluminium, or can manually enter “Tk” value. Values are entered in Celsius degrees. It is also needed to set temperatures of device under test and reference temperature to which the results are to be calculated. Measurement units It is possible to choose measurement units that will be displayed in saved Excel tables. Default measurement units are in A, mV and mΩ. If data should be saved for the first time in current RMOWin- T2M session, the question is displayed for setting the measurement units. If user does not want to set new units, then the default ones will be used for saving and printing measurement results. If the answer is Yes, then the following window is displayed, where user can choose measurement units. Changing the measurement units is also possible later.

8 Error Messages Any operational error is indicated by a red LED and accompanied by an alarm. Furthermore, the display indicates an error status message. To stop the alarm buzzer, remove the status message on the display, and return to the Curr menu, press the STOP button. 8.1 Error Message "Open connection" The Error message "Open connection" is displayed if: - it is either + or – current cable, or both disconnected either on the side of device, or the side of test object. 8.2 Error Message "Connection CH1-2", "Connection CH1" The Error message "Connection CH1-2" is displayed if both, CH1 and CH2 are not connected in the Curr mode. This message is displayed if either + or – voltage sense cable or both are disconnected either on the device side, or the side of the test object. The Error message "Connection CH1" is displayed only if CH1 is not connected in the TapC mode. This message is displayed if either + or – voltage sense cable or both are disconnected either on the device side, or the side of the test object. These messages are displayed only at the beginning of a test. Figure 8-1: Connecting a test object to RMO10T Voltage sense Ch:1, Ch:2 Current cables

8.3 Error Messages "Polarity" The Error messages "Polarity" is displayed if: the Voltage sense cables are connected with opposite polarity either on the side of a device, or the side of test object, and the signal is higher than 60mV. In some cases discharge LED can light alternately. This message is displayed only at the beginning of a test. Note: If the signal is lower than 60mV the display will show result with lower accuracy. If some of the cables are disconnected after starting the test, error message will not show up and the received results will be erroneous. 8.4 Error Message "Change Current" This message is displayed if during the test the voltage at the test object is too high. In this case reduce the test current and repeat the test. In case when test voltage is not higher than 10V per channel but test current is still improperly high for that resistance error message „Overcurrent“ is shown on the display. Red LED will light continuously. 8.5 Error Message "Overheat" This message is displayed when RMO10T’s operating temperature rises too high. In this case, wait for the test set to cool down and repeat the test. 8.6 Error Message "Mains Voltage < 90V" This message is displayed when RMO10T’s mains voltage is below 90V. In this case, to reset the status message you must restart RMO10T. Figure 8-4: Error message "Overheat" Figure 8-5: Error message "Mains Voltage < 90V" Figure 8-2: Error message "Change Current" Figure 8-3: Error message "Overcurrent"

The message "Error printer" is displayed if hardware error is apparent at the printer. Check weather black shaft is in proper position. If yes and the error occurs repeatedly, please contact IBEKO POWER AB (refer to section ”Manufacturer Contact Information”). The message "Check paper" is displayed if the printer is out of paper. The paper roll should be aligned with the paper intake without horizontal offset, and central axis of the paper roll must be parallel with the printer, as shown at Figure 8-7. Also, pay attention to insert paper in proper way to the printer, since it must enter paper intake from the lower side of paper roll. In case that the paper is not properly aligned, black shaft should be pulled up to loose the paper (see Figure 8-7). After that, align the paper and push down black shaft in proper position. Figure 8-7: Paper loading Figure 8-6: Error messages "Error printer" and "Check paper"

9 Technical Data 9.1 Mains Power Supply according to IEC/EN60320-1; UL498, CSA 22.2 - Voltage single phase 110 V – 240 V AC, +10% – -15% - Frequency 50/60 Hz 9.2 Output data - Test current 5 mA – 10 A DC - Typical Accuracy ±(0,2% rdg + 0,2% FS) 9.3 Environmental conditions - Operating temperature -10 oC - +50 oC/ 14 oF- +122 oF - Storage temperature -25 oC - +70 oC /-13 oF- +158 oF - Humidity 5%– 95% relative humidity, non condensing 9.4 Dimensions and Weight 198 mm x 255 mm x 380 mm (W x H x D) without handle 7,8 in x 10 in x 15 in - Weight 7,5 kg / 16,5 lbs 9.5 Safety Standards - European standards EN 61010-1 - International standards IEC 61010-1 UL 3111-1 CAN/CSA-C22.2 No 1010.1-92 9.6 Electromagnetic Compatibility (EMC) CE conformity EMC standard 89/336/EEC Emission EN 50081-2, EN 61000-3-2/3 Interference Immunity EN 50082-2 9.7 USB Interface RMO10T is equipped with an USB serial interface to connect to an external computer.

10 Accessories Standard Article No Current cables 2 x 10 m, 2,5 mm2 with battery clips Sense cables 2 x 2 x 10 m, 2,5 mm2 with alligator clips Current connection cable 1 x 5 m 6 mm2 RMOWin-T2M PC software including RS232 cable Mains power cable Ground (PE) cable Transport bags Additional Article No Current cables 2 x 15 m, 2,5 mm² with battery clips Sense cables 2 x 2 x 15 m, 2,5 mm2 with alligator clips Test shunt 75 A / 150 mV Transport case Manufacturer Contact Information IBEKO POWER AB Box 1346, 181 25 Lidingö, Sweden Fax: + 46 8 731 77 99 E-Mail: [email protected] Website: http://www.dv-power.com 1 nc not connected 2 TXD (out) Transmit Data 3 RXD (in) Receive Data 4 nc not connected 5 GND Ground 6 nc not connected 7 nc not connected 8 nc not connected 9 nc not connected Housing = shield