Vehicle Description
Vehicle Function and Operational Interlocks
Type DHR vacuum circuit breakers are comprised of the
interrupter/operator module fitted to a vehicle. This inter-
rupter/operator module is an integral arrangement of op-
erating mechanism, dielectric system, vacuum interrupt-
ers, and means of connecting the primary circuit. The ve-
hicle supports the interrupter/operator module, providing
mobility and fully coordinated application in Westinghouse
type DH switchgear.
This manual should be used jointly with the Circuit Breaker
Operator manual, SGIM-9918.
Alignment
All aspects of the circuit breaker structure which impact
alignment and interchangeability are checked at the fac-
tory. Field adjustment will not normally be required, but
variations in existing switchgear may require field adjust-
ment.
Recommended Tools
• Racking Crank: Original circuit breaker racking crank may
be used.
Installing Circuit Breaker Module Into Compartment
Note: CLOCKWISE ROTATION of racking for inserting
breaker. COUNTERCLOCKWISE ROTATION of racking
crank for removal of breaker.
Levering Device and Breaker Interlock
(Figure 1a and Figure 1b) shows the two extreme positions
of the of the levering device.
Levering-in Device
In order to move the breaker in or out of the metal clad cell
against the resistance of the contact fingers on the rear of
each bushing, a levering-in device is provided on each
breaker. There is an arm on each side mounted on a com-
mon shaft across the back of the breaker. On each arm is
a roller which engages a groove in the sidewall of the cell.
A removable crank engages another shaft in the right front
corner of the breaker which turns the arms through a worm
gear and pinion arrangement.
Hazardous voltages and high-speed
moving parts. Will cause death, serious
injury, and property damage.
De-energize before working on this equip-
ment.
Do not by-pass interlocks or otherwise make
interlocks inoperative.
4
Before a breaker is rolled into a cell, the arms with rollers,
at each side of the breaker must point to the rear and slightly
downward as shown in (Figure 1a). The arms travel 193
degrees and assume the horizontal position shown in (Fig-
ure 1b) when the breaker is cranked into the operating
position in the cell. To put the arms in the position shown
in (Figure 1a), place the crank on the operating shaft at the
front right corner of the breaker (Figure 3) push in, and
rotate to engage the coupling in the levering-in device. The
breaker contacts must be open to engage the coupling,
and the indicator will show “Interlocked”. Rotate the crank
counterclockwise to the end of the travel. During this time
the interlock mechanism will hold the coupling engaged.
At the end of the travel, the interlock will release, the crank
will move to the front, and the indicator on the mechanism
panel will point to the word “OPERATE”.
With the arms to the rear and down as shown in (Figure
1a), the breaker is ready to be rolled into the cell as far as
Figure 1a. Breaker out of the cell
Figure 1b. Breaker in the cell
