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5-1 Description
The PowerVac
5kV VL vacuum circuit breaker
®
uses a sealed vacuum power interrupter to es-
tablish and interrupt a primary circuit. Primary
connections to the associated metal-clad
switchgear are made by pole assemblies, elec-
trically and mechanically connected to the
vacuum interrupters. The operating mechanism
provides vertical motion at each pole location
in order to move the lower contact of the
vacuum interrupters from an open position to a
spring-loaded closed position and then back to
the open position on command.
The ML-19 mechanism (Figure 12) is a stored-
energy type mechanism and uses a gear motor
to charge a closing spring. During a closing op-
eration, the energy stored in the closing spring
is used to close the vacuum interrupter contacts,
charge the wipe springs which load the con-
tacts, charge the opening springs, and overcome
bearing and other frictional forces.
Figure 12. Front View of ML-19 Mechanism with Front Cover Removed
1
Opening Spring
2
Charging Motor
3
Close Spring
4
Manual Close Button
5
Charge/Discharge Indicator
6
Manual Trip Button
7
Open/Close Indicator
Courtesy of NationalSwitchgear.com
PowerVac
The energy then stored in the wipe and open-
ing springs will open the contacts during an
opening operation.
Closing and opening operations are controlled
electrically by the control switch on the metal-
clad door or remote relaying.
Mechanical control for maintenance or emergen-
cies is provided by manual close and trip but-
tons on the circuit breaker.
Also, the closing spring may be manually
charged (Figure 7) for de-energized checks and
maintenance.
8
Counter
9
Manual Charge Lever
10
Positive Interlock Switch
11
Close Relay
12
Cam shaft
13
Close coil
18
5kV Vertical Lift
®
Chapter 5. Operation
14
Close coil adjustment collar
15
Close latch check switch
16
Opening dashpot
17
Auzilary switch
18
MOC Plunger linkage
19
Positive interlock bar
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