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2

5.  Remove coil from magnet.
6.  Replace coil.
7.   Reassemble device by reversing 

procedure.

Contact removal
Movable contacts can be inspected  
and replaced in seconds —without  
tools (Figure 3).

1.   Perform steps 1 through 5 under  

coil replacement. 

2.  Remove complete magnet assembly  

by pulling entire assembly from the 
contactor assembly. 

3.  With the magnet assembly resting on 

its side, remove the movable arm by 
sliding it out the back of the assembly. 

4.  Depress movable contact and spring, 

and slide movable contact from 
movable arm. 

5.  Remove screws holding stationary 

contact in place and remove stationary 
contact.

6.  Reassemble by reversing the above 

procedure. When reassembling, note 
that the cover will fit only one way. 
Magnet and movable arm will fit either 
way but will be quieter if reassembled 
the same way they were taken apart.

NOTE: Do not attempt to remove or 
replace arc traps in arc chute cover. 

When reassembling, note that the arc 
chute cover will only fit one way and is 
marked “TOP” in upper right-hand corner. 

Check for welded contacts  
in overload relay 
This feature permits maintenance 
personnel to check for welded relay 
contacts by simply depressing the white 
operator located at the top of the overload 
relay contact housing. When the relay is in 
the reset condition, an audible “click” will 
be heard when the operator is depressed, 
indicating that the contacts are operating 
normally. A continuity check can also be 
made by disconnecting the control wiring 
from the terminals of the relay and placing 
a bell set or a resistance measuring 
instrument in the circuit. Connecting 
either of these across the relay terminals 
will indicate the relay contact is closed 
until the contact-check operator is 
depressed, opening the circuit. The 
exclusive manual contact operation check 
gives positive assurance that contacts 
have not welded due to short circuits in 
the control wiring.

Simple maintenance 
300/400-line starters and contactors 
require virtually no corrective 
maintenance. Preventive maintenance  
will assure many years of dependable  
on-line service. 
1.   Always remove power from device 

before performing any maintenance. 

2.  Keep magnet mating surfaces free  

of accumulated dirt or dust. 

3.  DO NOT OIL OR GREASE the magnet 

mating surfaces. 

4.  Contacts are carefully designed for 

maximum life. They need only be 
replaced when nearly all the silver tip  
is gone and the contact tip support is 
exposed. DO NOT FILE the contacts. 
Filing or otherwise dressing the 
contacts only results in lost tip material 
and reduces contactor or starter life. 

5.  The ultimate tripping current of the 

installed relay heater can be adjusted 
±10% by using adjustment dial.


Replacement coils
For two- and three-pole devices, order cat. no. 55-536548G plus number in table below.
Example: 55-536548G002 is rated 115–120 V, 60 Hz/110 V, 50 Hz.

Frequency

115–120 V

200–208 V

230–240 V

460–480 V

575–600 V

60 Hz

002

023

003

004

005

Frequency

110 V

220 V

380 V

440 V

550 V

50 Hz

002

003

064

004

005


Accessory kits

First NO auxiliary contact for CR305, CR306 (right-side mounting)

CR305X500A

First NC auxiliary contact for CR305, CR306 (right-side mounting)

CR305X500B

First NO-NC auxiliary contact for CR305, CR306 (right-side mounting)

CR305X500C

Additional NO auxiliary contact for all forms

CR305X100D 

Additional NC auxiliary contact for all forms 

CR305X100E

Surge suppressor

CR305X146C

Lug kit ( 1 lug and hardware)

55-186556G003


Figure 3 — reference diagram (representation only)

Stationary 
contact 
screws

Stationary 
contacts

Movable  

contacts

Movable arm 
return spring 
(not shown)

Spring seat

Spring

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