GE AK-2A-15 User Maintenance Manual Download Page 20

may be  replaced without removing the  device from 

the  breaker  by  proceeding  as  follows : 

1. 

Disconnect  leads  of  coil  (8). 

2.  Remove  two  screws  (6)  which  fasten  magnet 

(7) and  coil  to  the  frame  (2 ). 

3.  Having  removed  the  magnet  from the  device, 

straighten the end of clamp  ( 9). 

4. 

Remove  the  coil from the  magnet. 

5.  Install  new  coil,  again  forming  end of clamp 

(9)  as  shown. 

6.  Reassemble  to  frame. 

7. 

Connect  coil  leads. 

ADJUSTMENT 

The  only  adjustment  required  on  the  shunt 

trip  device  is  that  which  ensures  positively  that 

the  breaker  will  trip  when  the  device  is  activated. 

In  order  to  be  sure  of  this,  armature  arm  (11) 

must  travel  from  1/32  to  1/16  of  an inch beyond 

the  point  at  which  the  breaker  trips. 

A  good 

method  of  checking  this  is  to  hold  a  1/32nd shim 

between  the  magnet and armature at  (10)  and with 

the  breaker  closed,  push  upwards  at  (5

,  closing 

the  armature  against  the  magnet. 

If 

the breaker 

trips,  there  is  sufficient overtravel. 

If 

adjustment 

is  necessary,  trip  paddle  (12 )   may  be  formed 

towards  or  away  from  armature  arm  (11). 

PROTECTIVE  DEVICES 

An  AK-2/3  breaker  may  be  equipped  with 

the  following protective  devices : 

1 .   Overcurrent  trip  (Magnetic) AK-2 

2 .   Power Sensor  Trip  (Static)  AK-3 

3 .   Reverse  Current  Trip  AK-2 

4. 

Under Voltage  Trip 

Lockout  Device 

5. 

B ell Alarm and/or  Lockout  device 

6.  Open Fuse  lockout  device. 

7. 

AKD- 5  Interlock  AK-2A/ AK-3A 

OVERCURRENT  TRIP  DEVICE 

(Magnetic ) 

The  typical  overcurrent  trip  device  consists 

of  a  magnetic  structure,  a  series  current  coil, 

and  a  pivoted  armature. 

When  current  flow  through  the  series  coil 

generates  a  magnetic  field  strong  enough,  the 

armature  overcomes  the  restraining  force  of  a 

calibration  spring  attached to  it,  and closes against 

the  magnet. 

This  trips  the  breaker  by  means 

of  an  extension  on  the  armature  which  strikes 

against  a  trip  paddle  on  the  trip  shaft. 

Depending  on  the  type  of  individual  device, 

the  movement  of  the  armature  may  be  delayed 

for  a  time  by  a  timing  device. 

If 

a  relatively 

long  time-delay  (seconds  or  minutes)  is  desired, 

the  velocity  of  armature  movement  is  governed 

by  a  piston  moving  through  an  oil  dashpot. 

If 

only  a  short-time  delay  (cycles  or  milli-seconds) 

is  required,  movement  is  controlled by an  escape­

ment  gear  and pallets  arrangement. 

An  AK-2- 1 5/2 5  breaker may be  equipped with 

either  the  EC-2  or  EC- 1 overcurrent  trip  device. 

The  majority  of  applications  will  require  the  use 

of  the  EC-2  device.  The  EC- 1  device is  normally 

2 0  

used when the  short-time  delay feature i s  required, 

or when the  trip  device  is  used to operate a special 

over-current  alarm  switch. 

Most  circuit  breakers  are equipped with series 

overcurrent trip devices  either of the dual magnetic 

type  (instantaneous  and.  time  delay  tripping)  or 

instantaneous  alone. 

Breakers  are  designed  to 

carry  up  to  100%  of the  continuous  current rating 

of  their  trip  devices.  Any  attempt to  carry  higher 

currents  for  a  prolonged  period  will  cause  over­

heating  and  possible  damage .  

E C-2  OVERCURRENT  TRIP  DEVICE 

The  Type  EC-2  overcurrent  tripping  device 

is  available  in three  forms : 

1.  Dual  overcurrent  trip,  with  long-time  delay 

and  high-set  instantaneous  tripping. 

2 .   Low-set instantaneous  tripping . 

3. 

High- set  instantaneous  tripping. 

The  dual  trip  has  adjustable  long-time  and 

instantaneous  pick-up  settings  and  adjustable  time 

s ettings.  Both  forms  of  instantaneous  trips have 

adjustable  pick-up  settings . 

DUAL  OVERCURRENT  TRIP,  WITH  LONG- TIME 

DELAY  AND  HIGH-SET  INSTANTANEOUS  TRIP­

PING. 

By  means  of the adjustment knob (5), Figure 10, 

which  can  be  manipulated  by  hand,  the  current 

pick-up point can be  varied from  80 to  160 percent 

of  the  series  coil  rating. 

The  indicator  and  a 

calibration  plate 

(4), 

Figure  10,  on  the  front of 

the  case provide  a  means  of  indicating  the  pick-up 

point  setting  in  terms  of percentage  of  coil  rating. 

The  calibration  plate  is  indexed  at  percentage 

settings  of  80,  1 00,  120,  140  and  160. 

• 

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Summary of Contents for AK-2A-15

Page 1: ...nance Instructions Includes Supplement GEI 86153 GEI 50299E Power Circuit Breakers Types AK 2 2A 15 AK 2 3 2A 3A 25 AKU 2 3 2A 3A 25 GENERAL fj 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...

Page 2: ...Cut Off t Jwitch Closing Switch Shunt Trip Device PROTECTIVE DEVICES Overcurrent Trip Device EC 2 Overcurrent Trip Device EC 1 Overcurrent Trip Device Reverse Current Trip Devices Power lensor Trip D...

Page 3: ...forces the shorter end of the handle upwards against the bottom of the solenoid armature and closes the breaker The breaker may be tripped open by any one of a number of electrical tripping devices w...

Page 4: ...manual handle cam and mechanism connecting link The Tripping is accomplished by the manual trip button on the escutcheon or by any of the electrical tripping devices available for use on the standard...

Page 5: ...urrent carrying parts of the breaker and their supporting structure The procedure for this operation is as follows 1 Remove the arc quenchers see section on Arc Quenchers 2 Disconnect the two insulate...

Page 6: ...lease of tripping latch check mechanism latch adjustment Worn or damaged trip unit parts Replace trip unit Bind in overcurrent trip device Replace overcurrent trip device False Tripping Overcurrent tr...

Page 7: ...ts and external control circuits They are used only on drawout type breakers A terminal board serves the same purpose on stationary mountedandgeneral purpose enclosure mounted breakers The second ary...

Page 8: ...e rear side of the stationary contacts Each of the stationary contacts pivot in a horizontal plane approximately at their mid points The end of the contact opposite to the contact tip end is formed in...

Page 9: ...ontact replacement will call for re placement of all the movable and stationary con tacts at the same time This will be the case where long use of the breaker in service has resulted in extensive wear...

Page 10: ...r Base 8 Spring REPLACEMENT OF MOVAB LE C ONTACTS 18 Figure 3 1 Coat the pivot area only of the new movable contacts with a thin coat of D50H47 grease 2 Assemble the center pole movable contacts align...

Page 11: ...hould be adjustable using eccentric numbers 1 2 or 3 These numbers are the ones visible when viewing the breaker from the front not from above The higher numbers should be reserved for tightening at f...

Page 12: ...function properly it is best to first perform the available remedial measures listed in the Trouble Shooting chart of these instructions One of the remedies 12 listed is that of proper mechanism latch...

Page 13: ...position where the contacts move before tripping occurs When this position is established note the position of the slot in the head of the adjusting screw 4 Withdraw the adjusting screw three and one...

Page 14: ...e Arc Quencher 3 Disconnect the two insulated connecting links between the mechanism and the contacts as in step 2 of the procedure for Separation of Front and Back Frames 4 Remove the two elastic sto...

Page 15: ...bly In replacing the escutcheon it may be necessary to use pliers to pull the operating shaft fully into the escutcheon in order to have space enough to replace the flat washers and the soft retainer...

Page 16: ...g axis and withdraw it Replace new contacts by reversing the pro cedure slide downward until clear of armature Coil 6 Reassemble with new coil by reversing order of procedure X C ONTACTOR The X contac...

Page 17: ...s so that enough wire will remain for connection to the new relay Sufficient original wire is allowed for this purpose 2 JL_ lJ L c 3 4 5 After the old relay has been removed the wire leads to the rel...

Page 18: ...ide also holds a wiring cleat and spacer which serves to hold the wires clear of the link connecting the mechanism andthe breaker position indicator 4 Remove the front escutcheonfrom the breaker 5 Sli...

Page 19: ...Push Button 1 Nut 2 Frame 3 Spring 4 Rivet 5 Weight 5 Movable Contact 6 Spring 7 Hinge 8 Closing Solenoid _ L _ AUX SW LIC A7 M T C A M2 9 Speed Nut 10 Screw TRIP 3 1 1 Figure 9 695C161 Shunt Trip Dev...

Page 20: ...ice the movement of the armature may be delayed for a time by a timing device If a relatively long time delay seconds or minutes is desired the velocity of armature movement is governed by a piston mo...

Page 21: ...shpot Arm 8 Connecting Link 9 Instantaneous Pickup Calibration Marks counter clockwise motion decreases it The dash pot arm 7 Figure 1 1 is indexed at four points maximum 2 3 1 3 minimum from the left...

Page 22: ...instantaneous pick up value may have one of the following three ranges 4 to 9 times coil rating 6 to 12 times coil rating or 9 to 15 times coil rating The pick up setting may be varied by turning the...

Page 23: ...overcurrent trip devices have been replaced Positive tripping is achieved when adjustment screw 2 Figure 10 is in such a position that it will always carry the trip paddle on the trip shaft beyond the...

Page 24: ...against trip paddle 14 tripping thebreaker open ADJUSTMENTS The only adjustment to be made on the reverse current device is to make sure that the trip rod has a minimum overtravel of 1 32 of an inch...

Page 25: ...nciple that the instantaneous value of current flowing in the three conductors or in four conductors on four wire systems must add to zero unless ground current is flowing Therefore if the electrical...

Page 26: ...Power Sensor Successful operations in the test position should be ob tained before proceedingwith the Power Sensor trouble shooting 3 A PST 1 Power Sensor Test Kit must be available Figure 21 Check t...

Page 27: ...Coil Remotely Located 1 Terminal 2 External Ground Sensor Coil 3 White Polarity Dot 2 Check to be sure no continuity exists between R and A or between R and C 3 Temporarily connect jumper from shield...

Page 28: ...ngle phase testing unless the signal is shorted at the terminal board Figure 22 Jumper points 1 and 5 during overcurrent test The above considerations shouldindicate which of the four major components...

Page 29: ...C CONTtt ii IT R TO IEt O 1 tE tJi AL c 5RDUNO SEN SO COi l n n 75 11 Jt 50U R C E T P I C L f 0 JtJD F A JLT Co i E TiON eREAK E i 1 C t l 1 G eOuiJD SENSO OiSCO t4 IE i A NC ttlC T R NAl Gi OUNO 5SN...

Page 30: ...NGE AVA IL ABLE PER D E V ICE R A N G E OF 6 TO 12 T IMES IS F U RNISHED U N L E S S 1 f fi H I I I I I I O T H E RW I S E SPECIFI E D S E T T I NGIS ARE AT 12 T IM E S RATING r TOTA L cURVES ARE P L...

Page 31: ...TIIP liniNG Figure 25 109HL689 Time Curve 5 Unsolder three leads at ground disconnect and pull wire through hole in back frame On stationary breakers withfourthwire ground disconnect unsolder leads at...

Page 32: ...o wiring diagram 0102C3698 Figure 26 The voltage 208V AC or 230V AC to be monitored is connected to terminals 1 and 2 of the time delay box The undervoltage device 32 R T t C o N NE c T tr o c T O ME...

Page 33: ...unit is the faulty component A B Check input voltages across terminals 1 2 on static box These voltages should be as follows 1 Device 177L3 16 G 12 208 or 230volts A C 2 Device 177L316 G 14 125 volts...

Page 34: ...y device and its construction is similar The adjustments and replacement of t is device are the same as those described above for the static time delay undervoltage device UNDERVOLTAGE LOCKOUT DEVICE...

Page 35: ...eaker opens lever 2 rotates counterclockwise about pin 14 The motion is transmitted through links 1 and 13 to paddle 12 which operates bell alarm switch 11 If the device has the lockout feature the mo...

Page 36: ...wn to engage the trip shaft paddle in the tripped position 1 Figure 31 8041865 Open Fuse Lockout Device 1 Mounting Holes 2 Lever 3 Reset Button 4 Collor 5 Armature 6 Coil 36 4 2 Check that each armatu...

Page 37: ...embly of the existing backframe with the new front frame Addition of Shunt Trip Device Auxiliary witch Undervoltage Device Bell Alarm Lockout Device Drawout Mechanism Conversion to Elec Oper Covered B...

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...

Page 39: ...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: ...further information call or write your local General Electric Sales Office or Distribution Equipment Division 41 Woodford Avenue Plainville CT 06062 USA GENERAL fl ELECTRIC w w w E l e c t r i c a l P...

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