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INSTRUCTIONS 

TYPES 

IAC77A  FORM  800  AND  UP 

IAC77B  FORM  800  AND  UP 
IAC78A  FORM  800  AND  UP 
IAC78B  FORM  800  AND  UP 

TIME  OVERCURRENT  RELAYS 

GEK-34055C 

Supersedes  GEK-340558 

GENERAL

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ELECTRIC 

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Summary of Contents for IAC77B

Page 1: ...C77B FORM 800 AND UP IAC78A FORM 800 AND UP IAC78B FORM 800 AND UP TIME OVERCURRENT RELAYS GEK 34055C Supersedes GEK 340558 GENERAL ELECTRIC w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

Page 2: ...w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

Page 3: ...TANEOUS UNIT 9 SETTING THE INSTANTANEOUS UNIT 9 PICK UP TESTS 10 TARGET AND SEAL IN UNIT 10 PICK UP AND DROPOUT TEST 10 INSTALLATION TESTS 10 TIME OVERCURRENT UNIT 10 TARGET AND SEAL IN UNIT 10 INSTANTANEOUS UNIT 11 PERIODIC CHECKS AND ROUTINE MAINTENANCE 11 TIME OVERCURRENT UNIT 11 INSTANTANEOUS UNIT 11 TARGET AND SEAL IN UNIT 11 CONTACT CLEANING 11 SYSTEM TEST 11 SERVICING 11 TIME OVERCURRENT UN...

Page 4: ...w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

Page 5: ...elays for interphase faults residually connected can be utilized for single phase to ground faults Use of a is advantageous because it can be adjusted to provide more sensitive protection on connections for applying these relays are shown in Figures 14 and 15 A separate relay separate ground relay ground faults Typical In the application of IAC77 and 78 relays with automatic reclosing devices the ...

Page 6: ...w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

Page 7: ...s up it raises a target into view which latches up and remains exposed until released by pressing a button beneath the lower left corner of the cover The instantaneous unit is a small hinge type unit which may be mounted on the front to the right of the shaft of the time overcurrent unit Its contacts are normally connected in parallel with the contacts of the time overcurrent unit and its coil is ...

Page 8: ...w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

Page 9: ... 0 4 0 5 0 6 0 7 0 8 0 10 0 12 0 15 0 RATING 10 0 1 1 0 12 0 13 0 15 0 17 0 18 0 19 0 20 0 20 0 20 0 INSTANTANEOUS UNIT The instantaneous unit has a double wound coil for operation on either one of two ranges Any setting obtained in the lower range series connected is doubled within 3 when the unit is connected for high range operation parallel connected The instantaneous unit has a continuous rat...

Page 10: ... w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

Page 11: ...TABLE VII TAP 0 2 2 0 D C RESISTANCE 10 OHMS 7 0 13 MIN OPERATING AMPERES 0 25 0 2 2 0 CARRY CONT AMPERES 0 3 3 0 CARRY 30 AMPS FOR SEC 0 03 4 0 CARRY 10 AMPS FOR lSEC l 0 25 30 0 60 HZ IMPEDANCE OHMS 52 0 0 53 If the tripping current exceeds 30 amperes an auxiliary relay should be used the connections being such that the tripping current does not pass through the contacts or the target and seal i...

Page 12: ...w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

Page 13: ... 0 007 0 006 0 33 20 0 160 0 LOW 20 0 0 015 0 008 0 017 0 010 0 009 0 008 0 43 HIGH 40 0 0 004 0 002 0 004 0 002 0 002 0 002 0 10 Low means two windings connected in series High means two windings connected in parallel See Internal Connections diagram for additional information CHARACTER STICS Pick up of these relays is defined as the current required to close the contacts from the 0 5 time dial p...

Page 14: ... w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

Page 15: ...d be at least 1 32 wipe on the seal in contacts 4 The targets in the seal in unit and in the instantaneous unit must come into view and latch when the armatures are operated by hand and should unlatch when the target release lever is operated 5 Make sure that the fingers and shorting bars agree with the internal connections diagram CAUTION EVERY CIRCUIT IN THE DRAWOUT CASE HAS AN AUXILIARY BRUSH I...

Page 16: ...w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

Page 17: ...ctory to close its contacts from any time dial position at a minimum current within five per cent of the tap setting The unit resets at 85 percent of the minimum closing value PICKUP TEST Set the relay at the 0 5 time dial position and 2 0 amp tap Using the test connections of Figure 13 the main unit should close its contacts within 2 of tap value current l 96 2 04 amp TIME TEST Set the relay at t...

Page 18: ...w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

Page 19: ...he time dial to the ZERO TIME DIAL POSITION 1 Increase the current slowly until the seal in unit picks up See Table XI Move the time dial away from the ZERO TIME DIAL position the seal in unit should remain in the picked t up position Decrease the current slowly until the seal in unit drops out See Table XI TABLE XI TAP PICK UP DROPOUT CURRENT CURRENT 0 2 0 15 0 195 05 OR MORE 2 0 1 50 1 95 55 OR ...

Page 20: ...w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

Page 21: ...he Installation Section INSTANTANEOUS UNIT Check that the Instantaneous Unit picks up at the desired current level as outlined in the Acceptance Test Section TARGET AND SEAL IN UNIT 1 Check that the unit picks up at the values shown in Table XI 2 Check that the units drops out at 30 or more of tap value CONTACT CLEAN lNG For cleaning relay contacts a flexible burnishing tool should be used This co...

Page 22: ... w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

Page 23: ... setting is within the limits shown above Then set at 1 2 T D S and restore pick up by adjusting the resistor Compensation should be rechecked after the resistor adjustment With the contacts just open check the current required to just close the contacts on each of the other taps This current should be within 3 of tap value With the time dial at No 10 time setting and the tap plug in the 2 amp tap...

Page 24: ...w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

Page 25: ...should close with feeler gage in place TARGET AND SEAL IN UNIT Check steps 1 and 2 as described under Instantaneous Unit To check the wipe of the seal in unit insert a 0 012 inch feeler gage between the plastic residual of the armature and the pole piece with the armature held closed Contacts should close with the feeler gage in place RENEWAL PARTS It is recommended that sufficient quantities of r...

Page 26: ... w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

Page 27: ...GAG ING AUXILIARY BRUSH CONNECTING PLUG TRAVELS Y4 INCH BEFORE ENGAGING THE MAIN BRUSH ON THE TERMINAL BLOCK FIG 1 8025039 CROSS SECTION OF DRAWOUT CASE SHOWING POSITION OF AUXILIARY BRUSH 14 P ___ __ ____ ___ w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

Page 28: ...w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

Page 29: ..._ j JRUCTIONS TIME AMPERES INSTANTA1 1EOUS UNIT ADJUSTABL CORE TIME DIAL i ll DISK AND SHAFT INSTANTANEOUS TYPE I CYCLES UNIT MA IN STATIONARY BRUSH AND CONTACT ASSEMBLY MAGNET FIG 2 8041298 TYPE IAC77 800 SERIES RELAY REMOVED FROM CASE FRONT VIEW 15 w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

Page 30: ...w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

Page 31: ... UNIT RANGE SELECTOR LEADS GEK 34055 e FIG 3 8041297 TYPE IAC77 800 SERIES RELAY REMOVED FROM CASE REAR VIEH 16 0 CRADLE CAPACITOR w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

Page 32: ...w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

Page 33: ... SI T SI r 5 2 6 SHORT FI NGERS FIG 4 01 65A7758 0 TYPE IAC77A 800 SERIES RELAY INTERNAL CONNECTIONS FRONT VIEW 17 w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

Page 34: ... w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

Page 35: ...S UNIT B t V 7 NOTE INST UNIT CONNS lSHOWN ARE FOR LOW RANGE OPERATIO FOR HIGH RA NGE OPERATION CONNECT B 0 TO TERMI NAL 5 4 C 6 TO TERMINAL 7 FIG 5 0246A2200 l TYPE IAC77B 800 SERIES RELAY INTERNAL CONNECTIONS FRONT VIEW 18 l f w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

Page 36: ...w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

Page 37: ...NIT T SI Sl 1 5 2 6 SHORT Fl NGER FIG 6 0165A7781 0 TYPE IAC7RA 800 SERIES RELAY INTERNAL CONNECTIONS FRONT VIEW 19 w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

Page 38: ...w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

Page 39: ...Sl TARGET SEAL IN NOTE INSTANTANEOUS UNIT CONNECTIONS SHOWN ARE FOR LOW RANGE OPERATION FOR HIGH RANGE OPERATION CONNECT 8 0 TO TERMINAL 5 A 1C TO TERMINAL 7 FIG 7 0246A2286 l TYPE IAC78B 800 SERIES RELAY INTERNAL CONNECTIONS FRONT VIEW 20 1 i j t w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

Page 40: ...w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

Page 41: ...2 4 GEK 34055 OPERATING TIME RANGE FOR ANY PICKUP SETTING 6 MULTIPLES OF PICK UP FIG 8 K 6306872 5 TIME CURRENT CURVE OF THE INSTANTANEOUS UNIT 21 10 w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

Page 42: ...w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

Page 43: ... F REL Y TAP SETTING FIG 9 010888940 2 TIME ClJRRENT CHARACTERISTICS OF 50 H TYPES IAC77 AND IAC78 800 SERIES RELAYS 22 w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

Page 44: ...w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

Page 45: ...o 5 o 6 o 7 o s o 10 12 2 012 51 3 0 4 0_ 5 0_ fi O 7 0 8 0_ 10 0 12 15 _ l 1 t 10 1 t r t I b 5 4 __ I 3 i C 2 Ci 0 I I E 2 1 I 4 1 1 71111 II so 10 J I I I I Ill MULTIPLES OF RELAY TAP SETTING I I I I IIIII AOJ U5TMEHTS IHST UNIT COHTl NUOUSL Y AOJU STABLE 1 1 1 l 21 1 l I I z 0 2 1 Ill Ol a II I I I I IIIII FIG 10 088880274 5 TIME CURRENT CHARACTERISTICS OF 60 H TYPES IAC77 AND IAC78 800 SERIES...

Page 46: ...w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

Page 47: ...ILL 10 HOLES 19MM ISMM DRILL 2 HOLES CUTOUT MAY REPLACE DRILLED HOLES OPTIONAL 29 MM 1 1 6 PANEL ORILLlNG FOR 9JRFAC OUNTING TFRONT VIEW Fig 1 1 K 6209271 5 Outline and Panel Drilling for the IAC78B 800 Series Relay 24 t w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

Page 48: ...w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

Page 49: ...INE u VIEW SH NtiNG A5SEMB Y OF HAROWAFiE FOR SURfACE WTG ON STEEL PANELS L DRILLING FOR SURFAC LNTING FRONT lEVi FIG 12 K 6209270 2 OUTLINE AND PANEL DRILLING FOR TYPES IAC77A IAC778 AND IAC78A 800 SERIES RELAYS 25 w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

Page 50: ... w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

Page 51: ...XLA13 TEST PLUG VARIABLE RESISTOR TO TIMER START TO ACCURATELY REPRODUCE RELAY CHARACTERISTICS ALL TESTS SHOULD BE MADE WITH RELAY IN CASE MIN RECOMMENDED VOLTS 120 AT RATED FREQUENCY FIG 13 K 6154399 7 TEST CONNECTIONS FOR TESTING PICK UP AND TIME CURVE OF IAC RELAYS 26 _ w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

Page 52: ...w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

Page 53: ...1 1 5tH 1 1 l FIG 14 0246A6966 0 EXTERNAL CONNECTIONS OF FOUR IAC77A RELAYS USED FOR MULTI PHASE AND P ASE TO TO GROIJND FAULT PROTECTION OF A 3 PHASE CIRCUIT 27 w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

Page 54: ... w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

Page 55: ... 5 1 1 51H FIG 15 0246A6967 0 EXTERNAL CONNECTIONS OF FOUR IAC78A RELAYS PROTECTING A 3 PHASE CIRCUIT AGAINST MULTI PHASE AND PHASE TO GROUND FAULTS GENERAL ELECTRIC CO POWER SYSTEMS MANAGEMENT BUSINESS DEPT MALVERN PA 19355 c w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

Page 56: ...w w w E l e c t r i c a l P a r t M a n u a l s c o m w w w E l e c t r i c a l P a r t M a n u a l s c o m ...

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