EATON CORPORATION Cutler-Hammer
Chiller Starter (AMPGARD) Technical Data TD02003003E
Copyright 2006
3
Mechanical Non-Loadbreak Isolating Switch
400 Ampere Isolation Switch Front View
400 Ampere Isolation Switch Rear View
Isolation Switch
The Cutler-Hammer Type JMT-4, is a drawout, lightweight, 3-pole,
manually operated isolating switch mounted in the top of the starter
compartment. It may be easily removed by loosening two bolts in the
rear of the switch. The JRM-4 is rated 400 amperes continuous and is
used with both the 200 ampere and 400 ampere starters.
The component-to-component circuitry concept includes the mount-
ings for the current limiting fuses as part of the isolating switch.
A positive mechanical interlock between the isolating switch handle
mechanism and contactor prevents the isolating switch from being
opened when the contactor is closed or from being closed if the
contactor is closed.
An operating lever in the isolating switch handle mechanism is
designed to shear off if the operator uses too much force in trying to
open the non-loadbreak isolating switch when the contactor is
closed. This feature ensures that the operator cannot open the switch
with the main contactor closed, even if excessive force is used on the
operating handle.
To operate the isolating switch, the operating handle is moved
through a 180º vertical arc from the ON to the OFF position. In the
ON position, an operator on the back of the handle housing extends
through a bracket on the rear of the starter high voltage door, prevent-
ing the door from being opened with the switch closed. When the
high voltage door is open, a door interlock prevents the handle from
being inadvertently returned to the ON position.
When the operating handle is moved from ON to OFF, copper stabs
are withdrawn from incoming line fingers. As the stabs withdraw,
they are visible above the top of the fuses when viewed from the
front, and simultaneously grounded. As the fingers are withdrawn,
a spring-driven isolating shutter moves across the back barrier to
prevent front access to the line connections. As the shutter slides
into position, distinctive markings appear on the back barrier, making
it easier to check the position of the shutter. Refer to
Page 2
for an
illustration of this feature.
Switch Handle Closed
Switch Handle Open
Line Side Access Panel
(Removable From Front)
Isolation Switch Auxiliary Contacts
Line Side Connections
Optional Blown Fuse
Indicator Contacts
Switch
Operating
Arm
Control
Plug
