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Siemens 38-3AH3 38 kV Instruction Manual page 11

Vacuum circuit breaker
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5. Move the circuit-breaker release latch
(on the floor of the cell near the right
side of the circuit breaker) to the left
and pull the circuit breaker out from
the DISCONNECT position. The circuit
breaker can now be removed from the
cubicle and rolled out onto the two
extension rails.
6. Remove the circuit breaker from the
two extension rails using the approved
Siemens circuit-breaker lifting device or
Siemens lifting sling and a suitable
7. Lift the two extension rails and
withdraw them from the switchgear.
8. Close the circuit-breaker compartment
door and secure all latches.
Type 38-3AH3 vacuum circuit breakers
weigh between 800 and 1,000 lbs (364-
455 kg) depending upon ratings. The
circuit breaker can be moved using a
properly rated crane and lift sling. A lift
sling can be attached to the circuit breaker,
and then used to hoist the circuit breaker
vertically clear of the extension rails. When
clear, remove the rails and lower the circuit
breaker to the floor.
Installation checks and
functional tests
Heavy weight.
Can result in death, serious injury or property damage.
Do not transport a circuit breaker using a lift truck with the lift
truck in the raised position.
Racking crank engagement procedure
A crank for racking the circuit breaker is
provided as a standard accessory. Racking
a circuit breaker can be accomplished with
the drawout-compartment-front door
open or through a small opening (or
window) in the front door, with the door
closed. Racking a rollout-fuse truck is
accomplished with the compartment-front
door open.
The racking crank consists of an offset
handle with a custom socket assembly
welded to the end. The socket end of the
crank is designed to engage the shoulder
of the racking-mechanism shaft and
remain engaged during racking with spring
plungers. The plungers operate in a
manner similar to the retainers of an
ordinary mechanic's socket wrench.
The portion of the racking-mechanism
shaft visible is cylindrical, and the shoulder
of the racking-mechanism shaft is hidden
by a shroud until the engagement
procedure starts. The square socket-end of
the crank will only engage the shoulder of
the shaft if it is aligned properly.
Figure 2: Type 38-3AH3 vacuum
circuit breaker racking
Figure 3: Use of extension rails for
voltage transformer (VT) fuse-
rollout truck or circuit breaker not at
floor level (VT fuse-rollout truck in
upper cell shown. Procedure for
circuit breaker in lower cell but not
at floor level is similar.)



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