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2.0 BREAKER WITH MAGNETIC ACTUATOR MECHANISM
2.1 General
This is the latest innovative operating mechanism technology with the following salient
features,
Force generated by magnetic actuator
Latching by magnetic actuator
Release by magnetic actuator
No parts subjected to wear
Maintenance free as a standard feature
All the operating mechanism functions are integrated with the magnetic actuator. The
magnetic actuator provides perfectly suitable travel time and force travel characteristics
for vacuum switching devices.
2.2 Operating principle
The actuator is a bi-stable magnet system in which switching of the armature to the
relevant limit position is effected by the magnetic field of two electrically excited coils. The
field of two permanent magnets holds the armature magnetically in the limit positions.
Switching operations are released by excitation of one of the coils until the retaining force
of the permanent magnet is exceeded. Even on failure of auxiliary power, electrical
operation is still possible for a period of 200 seconds. The circuit breaker can then be
opened by the standard emergency manual operating system. The magnetic actuator is
designed in such a way that, the armature can acts directly via the lever on the main shaft,
on the moving contact of the vacuum interrupter. With this method of actuating force
generation and transmission, there is no wear of the mechanism. Maintenance up to
extremely high number of operating cycles is simply a thing of the past.
2.3 Conclusion and operation (Fig. 18, page no. 63)
The magnetic actuator used in the vacuum circuit breaker type OVB-SDB uses a
laminated yoke structure 1 to facilitate the permanent magnet 2 to hold the structure 5 in
the end positions. A pair of electromagnetic coils (3A and 3B) is used to drive the armature
between the two end positions. The temporary application of current of appropriate polarity
in the upper coil (3A) will cause a high flux to be forced across the upper air gap as shown
in fig 18,page no.63 providing an upward motive force on the armature 5 in order to close
the air gap. As the flux induced by coil (3A) is greater than the flux present in the lower
part of the magnetic circuit, the armature will be "flipped" to the upper position, which
corresponds to the upper limit position of the actuator. The armature will be held in that
position by the magnetic flux provided by permanent magnet.
Summary of Contents for OVB-SDB
Page 26: ......
Page 49: ...Fig 1 Lifting of Circuit Breaker 50 ...
Page 52: ...Fig 4 Breaker Pole Assembly Refer legend on pg 48 53 ...
Page 53: ...Fig 5 Schematic Circuit Diagram 54 ...
Page 55: ...15029 15027 15028 Fig 7 ESH Mechanism with Cabinet Refer legend on pg 49 56 ...
Page 60: ...Disconnect the motor power supply 7 Fig 15 Motor 61 ...
Page 62: ...Fig 18 The Magnetic Actuator 63 ...
Page 63: ...Notes ...
