ABB 41-101U Instruction Leaflet

2 Figure 1: Type CO Relay Without Case. 1 = Indicating Instantaneous Trip (IIT). 2 = IIT Adjusting Screw. 3 = Indicating Contactor Switch (ICS). 4 = Indicating Contactor Switch Tap Block. Figure 2: Time Overcurrent Unit (Front View). 1 = Tap block. 2 = Time Dial. 3 = Control Spring Assembly. 4 = Disc. 5= Stationary Contact Assembly. 6 = Magnetic Plugs. 7 = Permanent Magnet.

41-101U 3 Figure 3: “E” Type Electromagnet. 1= Magnet Plugs. 2= Tap Block. 3= Tap Screw. Figure 4: Indicating Instantaneous Trip Unit (IIT). Figure 5: Indicating Contactor Switch (ICS).

4 2.0 CONSTRUCTION AND OPERATION The type CO relays consist of an overcurrent unit (CO), an indicating contactor switch (ICS), and an in- dicating instantaneous trip unit (IIT) when required. The principal component parts of the relay and their location are shown in Figures 1 through 5. 2.1 ELECTROMAGNET The electromagnets for the types CO-5, CO-6, CO-7, CO-8 and CO-9 relays have a main tapped coil located on the center leg of an “E” type laminat- ed structure that produces a flux which divides and returns through the outer legs. A shading coil causes the flux through the left leg to lag the main pole flux. The out-of-phase fluxes thus produced in the air gap cause a contact closing torque. A torque controlled CO has the lag coil connections of the electromagnet brought out to separate terminals. This permits con- trol of the closing torque such that only when these terminals are connected together will the unit oper- ate. The electromagnets for the types CO-2 and CO-11 relays have a main coil consisting of a tapped prima- ry winding and a fixed secondary winding. Identical coils are on the outer legs of the lamination structure and are connected to the main coil fixed secondary in a manner so that the combination of all the fluxes produced by the electromagnet result in out-of- phase fluxes in the air gap. The out-of-phase air gap fluxes produced cause a contact closing torque. 2.2 INDICATING CONTACTOR SWITCH UNIT (ICS) The dc indicating contactor switch is a small clapper type device. A magnetic armature, to which leaf- spring mounted contacts are attached, is attracted to the magnetic core upon energization of the switch. When the switch closes the moving contacts bridge two stationary contacts, completing the trip circuit. Also during this operation two fingers on the arma- ture deflect a spring located on the front of the switch, which allows the operation indicator target to drop. The front spring, in addition to holding the target, provides restraint for the armature and thus controls the pickup value of the switch. 2.3 INDICATING INSTANTANEOUS TRIP UNIT (IIT) The instantaneous trip unit is a small ac operated clapper type device. A magnetic armature, to which leaf-spring mounted contacts are attached, is at- tracted to the magnetic core upon energization of the switch. When the switch closes, the moving contacts bridge two stationary contacts completing the trip cir- cuit. Also, during the operation, two fingers on the ar- mature deflect a spring located on the front of the switch which allows the operation indictor target to drop. Figure 6: External Schematic of the Circuit-Closing Type CO Relay for Phase and Ground Overcurrent Protection on a Three-Phase System. Sub 3 182A755

41-101U 5 ENERGY REQUIREMENTS TYPE CO-2 RELAY VOLT AMPERES** Continuous One Second Power At At 3 Times At 10 Times At 20 Times Ampere Rating Rating* Factor Tap Value Tap Value Tap Value Tap Value Range Tap (Amperes) (Amperes) Angle ø Current Current Current Current 0.5 0.91 28 58 4.8 39.6 256 790 0.6 0.96 28 57 4.9 39.8 270 851 0.8 1.18 28 53 5.0 42.7 308 1024 0.5/2.5 1.0 1.37 28 50 5.3 45.4 348 1220 1.5 1.95 28 40 6.2 54.4 435 1740 2.0 2.24 28 36 7.2 65.4 580 2280 2.5 2.50 28 29 7.9 73.6 700 2850 2.0 3.1 110 59 5.04 38.7 262 800 2.5 4.0 110 55 5.13 39.8 280 920 3.0 4.4 110 51 5.37 42.8 312 1008 2/6 3.5 4.8 110 47 5.53 44.3 337 1120 4.0 5.2 110 45 5.72 46.0 360 1256 5.0 5.6 110 41 5.90 50.3 420 1500 6.0 6.0 110 37 6.54 54.9 474 1800 4.0 7.3 230 64 4.92 39.1 268 848 5.0 8.0 230 50 5.20 42.0 305 1020 6.0 8.8 230 47 5.34 44.1 330 1128 4/12 7.0 9.6 230 46 5.53 45.8 364 1260 8.0 10.4 230 43 5.86 49.9 400 1408 10.0 11.2 230 37 6.60 55.5 470 1720 12.0 12.0 230 34 7.00 62.3 528 2064 VOLT AMPERES** Continuous One Second Power At At 3 Times At 10 Times At 20 Times Ampere Rating Rating* Factor Tap Value Tap Value Tap Value Tap Value Range Tap (Amperes) (Amperes) Angle ø Current Current Current Current 0.5 2.7 88 69 3.92 20.6 103 270 0.6 3.1 88 68 3.96 20.7 106 288 0.8 3.7 88 67 4.01 21.0 120 325 0.5/2.5 1.0 4.1 88 66 4.07 22.3 130 400 1.5 5.7 88 62 4.19 23.2 147 462 2.0 6.8 88 60 4.30 24.9 168 548 2.5 7.7 88 58 4.37 26.2 180 630 2 8.0 230 67 3.88 21.0 110 308 2.5 8.8 230 66 3.90 21.6 118 342 3 9.7 230 64 3.93 22.1 126 381 2/6 3.5 10.4 230 63 4.09 23.1 136 417 4 11.2 230 62 4.12 23.5 144 448 5 12.5 230 59 4.20 24.8 162 540 6 13.7 230 57 4.38 26.5 183 624 4 16.0 460 65 4.00 22.4 126 376 5 18.8 460 63 4.15 23.7 143 450 6 19.3 460 61 4.32 25.3 162 531 4/12 7 20.8 460 59 4.35 26.4 183 611 8 22.5 460 56 4.40 27.8 204 699 10 25.0 460 53 4.60 30.1 247 880 12 28.0 460 47 4.92 35.6 288 1056 * Thermal capacities for short times other than one second may be calculated on the basis of time being inversely proportional to the square of the current. ø Degrees current lags voltage at tap value current. ** Voltages taken with Rectox type voltmeter. CO-5 LONG TIME AND CO-6 DEFINITE MINIMUM TIME RELAYS

6 ENERGY REQUIREMENTS CO-7 MODERATELY INVERSE TIME RELAY VOLT AMPERES** Continuous One Second Power At At 3 Times At 10 Times At 20 Times Ampere Rating Rating* Factor Tap Value Tap Value Tap Value Tap Value Range Tap (Amperes) (Amperes) Angle ø Current Current Current Current 0.5 2.7 88 68 3.88 20.7 103 278 0.6 3.1 88 67 3.93 20.9 107 288 0.8 3.7 88 66 3.97 21.1 114 320 0.5/2.5 1.0 4.1 88 64 4.00 21.6 122 356 1.5 5.7 88 61 4.08 22.9 148 459 2.0 6.8 88 58 4.24 24.8 174 552 2.5 7.7 88 56 4.38 25.9 185 640 2 8.0 230 66 4.06 21.3 111 306 2.5 8.8 230 64 4.07 21.8 120 230 3 9.7 230 63 4.14 22.5 129 366 2/6 3.5 10.4 230 62 4.34 23.4 141 413 4 11.2 230 61 4.34 23.8 149 448 5 12.5 230 59 4.40 25.2 163 530 6 13.7 230 58 4.62 27.0 183 624 4 16 460 64 4.24 22.8 129 392 5 18.8 460 61 4.30 24.2 149 460 6 19.3 460 60 4.62 25.9 168 540 4/12 7 20.8 460 58 4.69 27.3 187 626 8 22.5 460 55 4.80 29.8 211 688 10 25 460 51 5.20 33.0 260 860 12 28 460 46 5.40 37.6 308 1032 CO-8 LONG TIME AND CO-9 DEFINITE MINIMUM TIME RELAYS VOLT AMPERES** Continuous One Second Power At At 3 Times At 10 Times At 20 Times Ampere Rating Rating* Factor Tap Value Tap Value Tap Value Tap Value Range Tap (Amperes) (Amperes) Angle ø Current Current Current Current 0.5 2.7 88 72 2.38 21.0 132 350 0.6 3.1 88 71 2.38 21.0 134 365 0.8 3.7 88 69 2.40 21.1 142 400 0.5/2.5 1.0 4.1 88 67 2.42 21.2 150 440 1.5 5.7 88 62 2.51 22.0 170 530 2.0 6.8 88 57 2.65 23.5 200 675 2.5 7.7 88 53 2.74 24.8 228 800 2 8.0 230 70 2.38 21.0 136 360 2.5 8.8 230 66 2.40 21.1 142 395 3 9.7 230 64 2.42 21.5 149 430 2/6 3.5 10.4 230 62 2.48 22.0 157 470 4 11.2 230 60 2.53 22.7 164 500 5 12.5 230 58 2.64 24.0 180 580 6 13.7 230 56 2.75 25.2 198 660 4 16.0 460 68 2.38 21.3 146 420 5 18.8 460 63 2.46 21.8 158 480 6 19.3 460 60 2.54 22.6 172 550 4/12 7 20.8 460 57 2.62 23.6 190 620 8 22.5 460 54 2.73 24.8 207 700 10 25.0 460 48 3.00 27.8 248 850 12 28.0 460 45 3.46 31.4 292 1020 * Thermal capacities for short times other than one second may be calculated on the basis of time being inversely proportional to the square of the current. ø Degrees current lags voltage at tap value current. ** Voltages taken with Rectox type voltmeter.

41-101U 7 VOLT AMPERES** Continuous One Second Power At At 3 Times At 10 Times At 20 Times Ampere Rating Rating* Factor Tap Value Tap Value Tap Value Tap Value Range Tap (Amperes) (Amperes) Angle ø Current Current Current Current 0.1 0.04 11.5 34 0.64 6.5 70.3 240 0.12 0.04 11.5 32 0.67 6.66 75.4 264 0.16 0.04 11.5 30 0.76 7.3 82.4 297 0.1/0.5 0.2 0.04 11.5 26 0.83 8.3 87.8 336 0.3 0.04 11.5 22 1.01 10.3 117.6 420 0.4 0.04 11.5 18 1.21 11.22 140.0 520 0.5 0.04 11.5 16 1.38 13.8 168.0 630 0.5 1.7 56 36 0.72 6.54 71.8 250 0.6 1.9 56 34 0.75 6.80 75.0 267 0.8 2.2 56 30 0.81 7.46 84.0 298 0.5/2.5 1.0 2.5 56 27 0.89 8.30 93.1 330 1.5 3.0 56 22 1.13 10.04 115.5 411 2.0 3.5 56 17 1.30 11.95 136.3 502 2.5 3.8 56 16 1.48 13.95 160.0 610 2.0 7.0 230 32 0.73 6.30 74.0 264 2.5 7.8 230 30 0.78 7.00 78.5 285 3 .0 8.3 230 27 0.83 7.74 84.0 309 2/6 3.5 9.0 230 24 0.88 8.20 89.0 340 4.0 10.0 230 23 0.96 9.12 102.0 372 5.0 11.0 230 20 1.07 9.80 109.0 430 6.0 12.0 230 20 1.23 11.34 129.0 504 4.0 14.0 460 29 0.79 7.08 78.4 296 5.0 16.0 460 25 0.89 8.00 90.0 340 6.0 17.0 460 22 1.02 9.18 101.4 378 4/12 7.0 18.0 460 20 1.10 10.00 110.0 454 8.0 20.0 460 18 1.23 11.1 124.8 480 10.0 22.0 460 17 1.32 14.09 131.6 600 12.0 26.0 460 16 1.8 16.3 180.0 720 * Thermal capacities for short times other than one second may be calculated on the basis of time being inversely proportional to the square of the current. ø Degrees current lags voltage at tap value current. ** Voltages taken with Rectox type voltmeter. ENERGY REQUIREMENTS TYPE CO-11 RELAY INSTANTANEOUS TRIP UNIT (IIT) RANGE IN BURDEN IN VOLT-AMPS AT AMPERES MINIMUM SETTING MAXIMUM SETTING 2 - 8 4.5 32 4 - 16 4.5 32 10 - 40 4.5 40 10 - 80 6.5 70 40 - 160 9.0 144

8 Figure 7: Typical Time Curves of the Type CO-2 Relay Sub 1 619584

41-101U 9 Figure 8: Typical Time Curves of the Type CO-5 Relay Sub 2 418245

10 Figure 9: Typical Time Curves of the Type CO-6 Relay Sub 2 418246

41-101U 11 *Sub 2 418247 Figure 10: Typical Time Curves of the Type CO-7 Relay *Denotes Change

12 Figure 11: Typical Time Curves of the Type CO-8 Relay Sub 2 418248

41-101U 13 Figure 12: Typical Time Curves of the Type CO-9 Relay. Sub 2 418249

14 Figure 13: Typical Time Curves of the Type CO-11 Relay. Sub 2 288B655

41-101U 15 A core screw accessible from the top of the switch provides the adjustable pickup range. 3.0 CHARACTERISTICS The relays are generally available in the following current ranges. These relays may have either single or double circuit closing contacts for tripping either one or two circuit breakers. The time vs. current characteristics are shown in Fig- ures 7 to 13. These characteristics give the contact closing time for the various time dial settings when the indicted multiples of tap value current are applied to the relay. 3.1 TRIP CIRCUIT The main contacts will close 30 amperes at 250 volts dc and the seal-in contacts of the indicating contac- tor switch will carry this current long enough to trip a circuit breaker. The indicating instantaneous trip contacts will close 30 amperes at 250 volts dc, and will carry this cur- rent long enough to trip a breaker. The indicating contactor switch has two taps that provide a pickup setting of 0.2 to 2 amperes. To change taps requires connecting the lead located in front of the tap block to the desired setting by means of a screw connection. 3.2 TRIP CIRCUIT CONSTANTS Contactor Switch - 0.2 ampere tap = 6.5 ohms dc resistance 2.0 ampere tap = 0.15 ohms dc resistance 4.0 SETTINGS CAUTION ! Since the tap block screw on both the CO unit and IIT unit carries operating current, be sure that the screws are turned tight. In order to avoid opening current transformer circuits when changing taps under load, the re- lay must be first removed from the case. Chassis operating shorting switches on the case will short the secondary of the current transformer. The taps should then be changed with the relay outside of the case and then re-inserted into the case. Range Taps † .1 - .5 0.1 0.12 0.16 0.2 0.3 0.4 0.5 .5 - 2.5 0.5 0.6 0.8 1.0 1.5 2.0 2.5 2.0 - 6.0 2.0 2.5 3.0 3.5 4.0 5.0 6.0 4.0 - 12.0 4.0 5.0 6.0 7.0 8.0 10.0 12.0 † Available for Type CO-11 Relay Only. Figure 14: Internal Schematic of the Double Trip Circuit Closing Relay. For the Single Trip Relay the Circuits Associated with Terminal 2 are Omit- ted. Figure 15: Internal Schematic of the Single Trip Circuit- Closing Relay with Indicating Instantaneous Trip Unit. Sub 3 57D4524 Sub 7 57D4525

16 4.1 CO UNIT The overcurrent unit settings can be defined either by tap setting and time dial position or by tap setting and a specific time of operation at some multiple of the current tap setting (e.g., 4 tap setting, 2 time dial position or 4 tap setting. 0.6 seconds at 6 times tap value current). To provide selective circuit breaker operation, a min- imum coordinating time of 0.3 seconds plus circuit breaker time is recommended between the relay be- ing set and the relays with which coordination is to be effected. The screw on the terminal plate above the time dial makes connections to various turns on the operating coil. By placing this screw in the various terminal plate holes, the relay will respond to multiples of tap value currents in accordance with the various typical time-current curves. 4.2 INSTANTANEOUS RECLOSING The factory adjustment of the CO unit contacts pro- vides a contact follow. Where circuit breaker reclos- ing will be initiated immediately after a trip by the CO contact, the time of the opening of the contacts should be a minimum. This condition is obtained by loosening the stationary contact mounting screw, re- moving the contact plate and then replacing the plate with the bent end resting against the contact spring. For double trip relays, the upper stationary contact is adjusted such that the contact spring rests solidly against the back stop. The lower stationary contact is then adjusted such that both stationary contacts make contact simultaneously with their respective moving contact. 4.3 INDICATING CONTACT SWITCH (ICS) The only setting required on the ICS unit is the selec- tion of the 0.2 or 2.0 ampere setting. This selection is made by connecting the lead located in front of the tap block to the desired setting by means of the connect- ing screw. 4.4 INDICATING INSTANTANEOUS TRIP ( IIT) The IIT setting is the level of ac current at which it will pickup. It should be set to coordinate with other de- vices so it will never operate for a fault in protective zone where tripping should be produced by other de- vices. The transient reach will not exceed 130% for an 80° circuit angle or 108% for a 60° circuit. The proper tap must be selected and the core screw must be adjusted to the value of pick-up current de- sired. 5.0 INSTALLATION The relays should be mounted on switchboard panels or their equivalent in a location free from dirt, moisture, excessive vibration and heat. Mount the re- lay vertically by means of the rear mounting stud or studs for the type FT projection case or by means of the four mounting holes on the flange for the semi-flush type FT case. Either the stud or the mount- ing screws may be utilized for grounding the relay. Ex- ternal toothed washers are provided for use in the lo- cations shown on the outline and drilling plan to facilitate making a good electrical connection be- tween the relay case, its mounting screws or studs, and the relay panel. Ground wires should be affixed to the mounting screws or studs as required for poorly grounded or insulating panels. Other electrical con- nections may be made directly to the terminals by means of screws for steel panel mounting or to the terminal stud furnished with the relay for thick panel mounting. The terminal stud may be easily removed or inserted by locking two nuts on the stud and then turning the proper nut with a wrench. Figure 16: Internal Schematic of the Single Trip Circuit- Closing Relay with Indicating Instantaneous Trip Unit. *Sub 5 182A754

41-101U 17 For detail information on the FT case refer to Instruc- tion Leaflet 41-076. 6.0 ADJUSTMENTS AND MAINTENANCE Proper adjustments for correct operation of this relay have been made at the factory. Upon receipt of the relay no customer adjustments, other than those covered under Section 4 "Settings" should be re- quired. For relays which include an indicating instantaneous trip unit (IIT), the junction of the induction and indi- cating instantaneous trip coils is brought out to switch jaw #3. With this arrangement the overcurrent units can be tested separately. 6.1 PERFORMANCE CHECK The following check is recommended to verify that the relay is in the proper working order: 6.1.1 Contact a. By turning the time dial, move the moving con- tacts until they deflect the stationary contact to a position where the stationary contact is resting against its backstop. The index mark located on the movement frame should coincide with the “O” mark on the time dial. For double trip relays, the follow on the stationary contacts should be ap- proximately 1/64”. a. For relays identified with a “T”, located at lower left of stationary contact block, the index mark on the movement frame will coincide with the “O” mark on the time dial when the stationary contact has moved through approximately one-half of its normal deflection. Therefore, with the stationary contact resting against the backstop, the index mark is offset to the right of the “O” mark by ap- proximately .020". The placement of the various time dial positions in line with the index mark will give operating times as shown on the respective time-current curves. For double trip relays, the fol- low on the stationary contacts should be approximately 1/32”. 6.1.2 Minimum Trip Current Set the time dial to position 6 using the lowest tap setting, alternately apply tap value current plus 3% and tap value current minus 3%. The moving contact should leave the backstop at tap value current plus Figure 17: Internal Schematic of the Double Trip Circuit Closing Relay with Torque Control Terminals. For the Single Trip Relay, the Circuits Associ- ated with Terminal 2 are Omitted. Figure 18: Internal Schematic of the Single Trip Circuit ClosinF:g Relay with Torque Control Termi- nals and Indicating Instantaneous Trip Unit. CO IIT IIT CO TERMINAL CHASSIS OPERATED SHORTING SWITCH CURRENT TEST JACK TEST SWITCH RED HANDLE INDICATING INSTANTANEOUS UNIT INDUCTION UNIT LAG COIL INDUCTION UNIT ICS ICS INDICATING CONTACTOR SWITCH CLOSE FOR RELAY TO TRIP EXTERNAL CONTACTS MUST FRONT VIEW 2 4 3 1 5 6 8 10 7 9 *Sub 7 57D4529 9 7 10 8 6 5 1 3 4 2 FRONT VIEW EXTERNAL CONTACTS MUST CLOSE FOR RELAY TO TRIP INDICATING CONTACTOR SWITCH ICS INDUCTION LAG COIL RED HANDLE TEST SWITCH CURRENT TEST JACK CHASSIS OPERATED SHORTING SWITCH TERMINAL CO CO CO ICS INDUCTION UNIT UNIT *Sub 5 57D4528

18 3% and should return to the backstop at tap value current minus 3%. 6.1.3 Time Curve For type CO-11 relay only, the 1.30 times tap value operating time from the number 6 time dial position is 53.5 ±5% seconds and should be checked first. It is important that the 1.30 times tap value current be maintained accurately. The maintaining of this cur- rent accurately is necessary because of the steep- ness of the slope of the time-current characteristic (Figure 13). A slight variation, ±1%, in the 1.3 times tap value current (including measuring instrument deviation) will change the timing tolerance to ±10% and the effects of different taps can make the total variations appear to be ±15%. Table 2 shows the time curve calibration points for the various types of relays. With the time dial set to the indicated position and the relay set on the lowest tap setting, apply the currents specified by Table 2, (e.g., for the CO-2, 3 and 20 times tap value current) and measure the operating time of the relay. The op- erating times should equal those of Table 2 plus or minus 5% (Use .5 tap for .1 to .5 range). 6.1.4 Indicating Instantaneous Trip Unit (IIT) The core screw which is adjustable from the top of the trip unit determines the pickup value. The trip unit has a nominal ratio of adjustment of 1 to 4 and an ac- curacy within the limits of 10%. The making of the contacts and target indication should occur at approximately the same instant. Po- sition the stationary contact for a minimum of 1/32” wipe. The bridging moving contact should touch both stationary contacts simultaneously. Apply sufficient current to operate the IIT. The oper- ation indicator target should drop freely. 6.1.5 Indicating Contactor Switch (ICS) Close the main relay contacts and pass sufficient dc current through the trip circuit to close the contacts of the ICS. This value of current should be not great- er than the particular ICS tap setting being used. The operation indicator target should drop freely. For proper contact adjustment, insert a .030" feeler gauge between the core pin and the armature. Hold the armature closed against the core pin and gauge and adjust the stationary contacts such that they just make with the moving contact. Both stationary con- tacts should make at approximately the same time. The contact follow will be approximately 1/64” to 3/64”. 6.2 CALIBRATION Use the following procedure for calibrating the relay if the relay has been taken apart for repairs or the ad- justments disturbed. This procedure should not be used until it is apparent that the relay is not in proper working order. (See Section 6.1, Performance Check.) 6.2.1 Contact a. By turning the time dial, move the moving con- tacts until they deflect the stationary contact to a position where the stationary contact is resting against its backstop. The index mark located on the movement frame should coincide with the “O” mark on the time dial. For double trip relays, the follow on the stationary contacts should be ap- proximately 1/64”. b. For relays identified with a “T”, located at lower left of stationary contact block, the index mark on the movement frame will coincide with the “O” mark on the time dial when the stationary contact has moved through approximately one-half of its normal deflection. Therefore, with the stationary contact resting against the backstop, the index mark is offset to the right of the “O” mark by approximately .020". The placement of the vari- ous time dial positions in line with the index mark will give operating times as shown on the respec- tive time-current curves. For double trip relays, the follow on the stationary contacts should be ap- proximately 1/32”. 6.2.2 Minimum Trip Current The adjustment of the spring tension in setting the minimum trip current value of the relay is most con- veniently made with the damping magnet removed. With the time dial set at “O”, wind up the spiral spring by means of the spring adjuster until approximately 6 3/4 convolutions show. Set the relay on the minimum tap setting, the time dial to position 6. Adjust the control spring tension so that the moving contact will leave the backstop at tap value current +1.0% and will return to the backstop at tap value current -1.0%. 6.2.3 Time Curve Calibration Install the permanent magnet. Apply the indicated current per Table 2 for permanent magnet adjust- ment (e.g., CO-8, 2 times tap value) and measure

41-101U 19 the operating time. Adjust the permanent magnet keeper until the operating time corresponds to the value of Table 2. For type CO-11 relay only, the 1.30 times tap value operating time from the number 6 time dial position is 53.5 ±5% seconds. It is important that the 1.30 times tap value current be maintained accurately. The maintaining of this current accurately is neces- sary because of the steepness of the slope of the time-current characteristic (Figure 13). A slight vari- ation ±1%, in the 1.3 times tap value current (includ- ing measuring instrument deviation) will change the timing tolerance to ±10% and the effect of different taps can make the total variations appear to be ±15%. If the operating time at 1.3 times tap value is not within these limits, a minor adjustment of the control spring will give the correct operating time without any undue effect on the minimum pick-up of the relay. The check is to be made after the 2 times tap value adjustment has been completed. Apply the indicated current per Table 2 for the elec- tromagnet plug adjustment (e.g., CO-8, 20 times tap value) and measure the operating time. Adjust the proper plug until the operating time corresponds to the value in Table 2. (Withdrawing the left hand plug, front view, increases the operating time and with- drawing the right hand plug, front view, decreases the time.) In adjusting the plugs, one plug should be screwed in completely and the other plug run in or out until the proper operating time has been ob- tained. Recheck the permanent magnet adjustment. If the operating time for this calibration point has changed, readjust the permanent magnet and then recheck the electromagnet plug adjustment. 6.2.4 Indicating Contactor Switch (ICS) Close the main relay contacts and pass sufficient dc current through the trip circuit to close the contacts of the ICS. This value of current should be not great- er than the particular ICS tap setting being used. The operation indicator target should drop freely. 6.2.5 Indicating Instantaneous Trip Unit (IIT) The core screw must be adjusted to the value of pick-up current desired. The nameplate data will furnish the actual current range that may be obtained from the IIT unit. 6.3 ROUTINE MAINTENANCE All relays should be inspected and checked periodi- cally to assure proper operation. Generally a visual inspection should call attention to any noticeable changes. A minimum suggested check on the relay system is to close the contacts manually to assure that the breaker trips and the target drops. Then re- lease the contacts and observe that the reset is smooth and positive. If an additional time check is desired, pass second- ary current through the relay and check the time of operation. It is preferable to make this at several times pick-up current at an expected operating point for the particular application. For the .5 to 2.5 am- pere range CO-5 and CO-6 induction unit use the al- ternative test circuit in Figure 16 as these relays are affected by a distorted wave form. With the connec- tion the 25/5 ampere current transformers should be worked well below the knee of the saturation (i.e., use 10L50 or better). All contacts should be periodically cleaned. A con- tact burnisher #182A836H01 is recommended for this purpose. The use of abrasive material for clean- ing contacts is not recommended, because of the danger of embedding small particles in the face of the soft silver and thus impairing the contact. 7.0 RENEWAL PARTS Repair work can be done most satisfactorily at the factory. However, interchangeable parts can be fur- nished to the customers who are equipped for doing repair work. When ordering parts, always give the complete nameplate data.

20 Table 2: TIME CURVE CALIBRATION DATA - 50 & 60 HERTZ PERMANENT MAGNET ADJUSTMENT ELECTROMAGNET PLUGS TIME CURRENT OPERATING CURRENT OPERATING RELAY DIAL (MULTIPLES OF TIME (MULTIPLES OF TIME TYPE POSITION TAP VALUE) SECONDS TAP VALUE) SECONDS CO - 2 6 3 0.57 20 0.22 CO - 5 6 2 37.80 10 14.30 CO - 6 6 2 2.46 20 1.19 CO - 7 6 2 4.27 20 1.11 CO - 8 6 2 13.35 20 1.11 CO - 9 6 2 8.87 20 0.65 CO -11 6 2 11.27 20 0.24 ∆ ∆ For 50 Hertz CO-11 relay 20 times operating time limits are 0.24 + 10%, -5%.

22 *Denotes Change Figure 19: Outline and Drilling Plan for the Type CO Relay in the Type FT-11 Case *Sub 19 57D7900

41-101U 23 Figure 20: Internal Schematic of the Double Trip Circuit Closing Relay with Indicating Instantaneous Trip Unit. Figure 21: Internal Schematic of the Double Trip Circuit Closing Relay with Indicating Instantaneous Trip Unit to Separate Terminals. Sub 5 57D4526 Sub 3 184A061

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