Richards 137NP, Инструкция по эксплуатации, Страница: 34 / 53

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Figure 13 – Motor Control Device
I. Motor Control Device
The motor control device is mounted in the lower left-hand side of the closing mechanism
assembly (see Figure 2). This device (see Figure 13) performs the necessary functions of
energizing the motor when the closing contacts on the relays close, and of de-energizing the
0motor after the breaker is completely closed. The device consists essentially of two
contacts connected in parallel, an individual latch for latching each contact in the open
position, a coil and plunger for releasing both contact latches when energized, and a lever
arrangement whereby two small cams on the main closing cam shaft will mechanically open
the contacts independently. These two small cams for opening the contacts are staggered on
the shaft such that either one or the other contact is always free to close. The location of
these cams on the shaft is such that the second contact is not opened until after the breaker is
latched in the closed position. Before either contact is opened during a closing operation the
“b” switch has opened and has de-energized the coil of the control device.
This device should be adjusted to pick up electrically as approximately 80 percent of the
normal motor circuit voltage (see
INSPECTION AND TESTING ). This must be checked
with an instantaneously applied voltage. To adjust this pickup, secure holding nut and turn
calibrating nut in a clockwise direction to decrease the voltage required to pick up armature.
To increase the pickup voltage, reverse the above procedure. The contacts of this device
must be latched open when in stalling protector in system.