NEMA size 0 & 1
Before installing in a nuclear
application, determine that the product is
intended for such use.
before Installing or servicing.
General Electric 300/400-Line full-voltage
motor starters include a magnetic
contactor and a three-leg block overload
relay, providing motor protection against
running and stalled motor overloads. The
overload relay is provided with a yellow
trip indicator located to the right of the
reset arm, and is visible when the
overload relay is tripped
Figure1.Typical 300/400-Line magnetic starter
Ratings—600 V Maximum
Motor branch circuit and control circuit
over- current protection should be
supplied in accordance with the
contactors are suitable for use on a
circuit capable of delivering not more
than 5,000 RMS symmetrical amperes,
600 volts maximum when protected by
H, J, K1, K5, RK1, RK5 class fuses, or a
circuit breaker having an interrupting
rating not less than 5,000 RMS
Before connecting controller to power
1. Remove all packing.
2. Clean magnet mating surfaces of any
dirt or foreign matter.
3. Select and install heaters in accordance
with heater table.
4. Operate movable magnet and operating
arm by pressing on the nameplate to
assure free movement.
5. Mount on a sturdy vertical support.
6. Make the electrical connections.
7. The starter overload relay may be reset
manually by depressing and releasing the
1. Remove power from device.
2. Press against coil while pulling up
slightly on coil retainers (A—Figure 1) and
move retainers away from coil.
3. Withdraw magnet assembly, coil,
molded cover, and movable arm from
4. Withdraw spring clip (B—Figure 1) and
remove armature from movable arm.
For AC Motors
5. Remove coil from magnet.
6. Replace coil.
7. Reassemble device by reversing
1. Perform steps 1 through 5 under
2. Remove magnet from molded cover
and movable arm.
3. Remove return spring from center
of movable arm.
4. Remove molded cover from
5. Depress and slide movable contact
and spring from movable arm.
CR307-CR308, CR310-CR311, CR387, CR390, CR407-CR408
CR410-CR415, CR487, CR490, CR492, CR494 Series
6. Remove screws holding stationary
contacts in place and remove stationary
7. Reassemble device by reversing
Note: For starters with one or more
normally closed contacts, perform steps
1 and 2 shown under Coil Replacement.
Withdraw spring clip (B—Figure 1) and
remove armature, coil, and magnet from
device. Remove return spring from center
of movable arm. Remove molded cover
and stationary contacts before lifting
movable arm from device.
Normally Closed Contacts
The contacts may be converted from
normally open to normally closed with no
additional parts. Perform steps 1 through
4 shown under Coil Replacement. Lift coil
and magnet from movable arm. Remove
return spring from center of movable
arm. Depress movable contact spring
and spring seat against movable contact
and rotate these parts 1/2 turn without
removing them from window. Remove
the stationary contacts. Install the
movable arm in the device. Install the
stationary contacts so that their silver
pads face the movable contact silver
pads. Reassemble the device. To change
contacts from normally closed to
normally open position, reverse the
Check For Welded Contacts In
With power disconnected, disconnect
the control wiring from the relay
terminals. Place a bell set or resistance
measuring instrument across relay
terminals. Depress and release reset
arm to insure relay is reset