13
Instruction Book
IB02707112E
August 2015
50/75VCPW-VSR
Breaker To Vacuum Starter Replacement Unit
EATON CORPORATION www.eaton.com
Figurt 4.3. SL CNnoacoNrs Asstmbly
4.2 ELECTRO-MOC
Installation / Operation / Ratings
Overview
MV-VSR vacuum starter replacements are designed for thousands of
mechanical operations. The mechanisms utilize solenoids for closing
and have limited excess kinetic energy and travel to operate auxiliary
devices. Mechanism Operated Contact (MOC) switch operation
requires more kinetic energy than the MV-VSR can deliver, so an
alternative must be utilized when MOC operation is required. Eaton
offers an electrical state-changing relay for this function. It does not
require an electrical latch. Eaton calls this an “Electro-MOC”. The
Electro-MOC can be installed in place of or used in conjunction with
the exiting MOC and has sufficient “a” and “b” contacts for most
applications. (Figure 4.4)
Figurt 4.4. EltcorN-MOC
Contactor Closed
1
Armature Shaft
4
Operating Plate
2
Moving Armature
5
Overtravel
3
Stop
Contactor Open
1
Armature Shaft
4
Operating Plate
2
Moving Armature
5
Return Spring
3
Stop
1
2
3
4
5
1
2
3
4
5
Installation
Installation is simple. The Electro-MOC may be mounted to either
a horizontal or vertical surface, but horizontal is preferred. The
mounting location should also have sufficient room and access for
control power and a/b contact wiring. (Figure 4.6)
An “order-specific” wiring diagram and schematic is furnished with
each MV-VSR for field connections. The information also provides
details for interfacing to an existing MOC switch. The original “a”
contacts must be wired in parallel with the “a” contacts on the
Electro-MOC. The original “b” contacts must be wired in series with
the “b” contacts on the Electro-MOC. It is suggested that polarized
voltages should not be used on adjacent contacts. This is because
of the remote possibility of flashover during transition between
adjacent contacts, especially at higher DC ratings or in highly
inductive circuits.
Further clarification is provided in the “order-specific” information.
(Figure 4.8)
Operation
The operation of the Electro-MOC requires an available (free)
“a” and “b” contact in the existing breaker and/or MV-VSR. An
interposing relay may also be used when “a” and “b” contacts are
unavailable. These contacts are used to operate the Electro-MOC.
The diagrams provided with the order include this information.
When the VSR, air circuit breaker, or vacuum replacement (described
as a switching device) is opened or closed, the Electro-MOC coil is
energized through the external breaker/interposing relay contacts,
changes state and is mechanically latched in the new configuration
until the coil is reenergized. The contacts selected to control the
Electro-MOC coil require ratings for “making only”. The Electro-MOC
has internal contacts to break the circuit.
Ratings
The Electro-MOC relay has been tested to many different circuit
conditions. The interrupting ratings are based on 10,000 life-
operations, using suddenly applied and removed rated voltage, with
no extensive burning of contacts. The interrupting rating column
headed “double contacts” means two contacts in series. Short-time
and continuous ratings are based on temperature rise in contact
members and supporting parts not exceeding 50°C above ambient.
WARNING
THIS VACUUM STARTER REPLACEMENT IS NOT DESIGNED TO OPERATE A
SEPARATE EXTERNAL AUXILIARY SWITCH (MOC SWITCH).
