30
VM1/A/P
- INSTALLATION AND SERVICE INSTRUCTIONS ANSI: ... 15 KV; ... 2000 A; ... 31.5 K A
—
7. Operation
Magnetic latching in end-of-run position.
Magnetic latching and action of the magnetic
field of a coil.
Moving armature in opposing position and
magnetic end-of-run latching.
Fig. 12
7.1. Circuit breaker function
Magnetic actuator (Refer to
figure 10b)
The magnetic actuator used in the VM1/A/P circuit
breaker generates the run required to operate the
moving contacts of the interrupters and integrates
all the functions of a traditional operating
mechanism.
The magnetic actuator is the heart of the circuit
breaker operating mechanism. It combines the
following integrated functions:
• Latching in the limit positions
• Release
• Switching
The actuator is a bistable permanent magnet
system in which the armature (13) motion is
affected by activating the close (11) and open (14)
coil. In the limit positions the armature is held in
place magnetically by the field of two permanent
magnets (12). Changing of the switched position is
performed by exciting one of the two coils until the
latching force of the permanent magnets are
exceeded.
The capacitors which allow circuit breaker
operation, for a maximum time of two minutes,
even in the case of a drop in the auxiliary voltage,
are provided in the control circuit. In case of
emergency, the circuit breaker can in any case be
opened by means of a special crank handle which
acts directly on the moving armature of the drive
(15).
7.2. Circuit breaker control
All the conditions for control of the magnetic
actuator mechanism are defined in a permanently
programmed logic module. These conditions are:
•
Auxiliary voltage must be applied to the AC/DC
converter.
•
The storage capacitor must have sufficient charge
for the next switching operation.
•
The moving contacts in the circuit breaker poles
must be in a defined CLOSE or OPEN limit position.
•
The closing coil can only be activated with the
circuit breaker in the OPEN position.
The opening coil can only be activated with the
circuit breaker in the CLOSE position.
•
Closing is blocked when an opening command is
simultaneously active.
•
Activation of the closing coil can be disabled by an
external blocking signal.
•
The antipumping system ensures that, when a
closing command is applied and followed by an
opening command, only one CLOSE-OPEN switching
operation is performed. For the next closing
operation, the active closing command has to be
cleared and must be issued again.
•
Deactivation of the opening or closing coil takes
place when the relevant limit position has been
reached.
Swich position:
Storage capacitor energy for:
Open
Close and Open
Closed
Open
Summary of Contents for VM1/A/P
Page 49: ...MEDIUM VOLTAGE PRODUCTS 49 49 ...
Page 51: ...MEDIUM VOLTAGE PRODUCTS 51 51 ...
Page 53: ...MEDIUM VOLTAGE PRODUCTS 53 53 ...
