background image


Figure 1 — reference diagram (representation only)

A

Coil

B

Overload relay

Heater slots

Magnet  
assembly

Adjustment 
dial

C


Figure 2 — reference diagram (representation only)

Magnet 
assembly

Overload relay

Circuit breaker 

or molded 

case switch

Pilot devices

Accessories

Lifting brackets 
(not shown)

1

CAUTION

Before installing in a nuclear application, 
determine that the product is intended  
for such use.

WARNING

Disconnect power before installing  
or servicing.


Ratings

Max. 
voltage

Max. 

continuous 

amp rating

AC volts

Max. HP for 

AC motors

Poly-phase

600

540

200

150

230

200

460/575

400

Description
An ABB 300/400-line full voltage magnetic 
motor starter consists of a magnetic 
contactor with a three-leg block overload 
relay and a manually operated circuit 

breaker or disconnect switch. The 
disconnect switch may either be fusible  
or non-fusible. The non-fusible disconnect 
switch provides a means of manually 
disconnecting the motor from the line. 
The circuit breaker or fusible disconnect 
switch provides motor branch short-
circuit protection. The overload relay 
provides motor protection against 
running and stalled motor overload.
 
The overload relay is provided with a 
yellow trip indicator, located to the right 
of the reset arm and visible when the 
overload relay is tripped.

Features
1.  Strongbox coil.
2.  Overload relay, incorporates a dial  

for ±10% field adjustment of tripping 
current, so that it is no longer 
necessary to change heaters to 
eliminate such problems as nuisance 
tripping in hot weather.

3.  Overload trip indicator.
4.  Straight-through wiring.

5.  Oversized power terminals will 

accommodate up to 2 runs of  
500 MCM wire.

6.  Starter can be disassembled and 

inspected in a matter of seconds. 

7.  Circuit breaker or disconnect switch  

is mechanically interlocked with the 
enclosure door to prevent opening  
the door until the handle is moved  
to the OFF position.

Installation
Before connecting the starter:
1.  Remove all packing.
2.  Clean magnet mating surfaces  

of any dust or foreign matter.

3.  Select heaters in accordance with 

heater table, which accompanies  
each device.

4.  Operate movable magnet and 

operating arm by pressing on the 
nameplate to assure free movement.

5.  Mount the starter on a sturdy  

vertical support.

6.  The overload relay may be reset 

manually by depressing and releasing 
the reset arm. Overload relays with an 
optional normally open contact are 
electrically isolated from the normally 
closed contact.

7.  Provide motor branch circuit protection 

in accordance with the National 
Electrical Code.

Coil removal
The encapsulated coil is impervious to 
moisture, dirt and oil. It resists mechanical 
damage and failure due to high humidity. 
No tools are required to remove coil.
1.  Remove power from device.
2.  Unscrew one end of the retainer (B — 

figure 1) and slide it out of the slot.

3.  Remove movable magnet assembly.
4.  Loosen four coil retainer screws (C — 

figure 1) . Press against coil and pull up 
and out on coil retainers (A — figure 1).

— 

INSTA LL ATION INSTRUC TIONS FOR NEM A SIZE 6 

300/400-line magnetic motor starters

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