| Tweet |
Custom Search
|
|
|
||
 TM 55-1905-220-14-7
3-205. HYDRAULIC CUB PUMP UNIT - MOTOR CONTROLLER - MAINTENANCE
INSTRUCTIONS.
A.
GENERAL
(1)
The motor controller is an A-C across-the-line non-reversing unit that controls the three-phase
electric motor used with the hydraulic pump on the steering system.
(2)
The controller contains a LOCAL-OFF-REMOTE switch and a RESET control on the front panel
and houses a line contactor, power transformer, control relay, and fuses. The controller is used with a steering
panel which provides remote control of the motor starter. In such an installation, the control switch is normally
in its REMOTE position. For testing purposes, the switch can be turned to the LOCAL position, thereby
energizing the contactor coil. In the OFF position, the contactor control circuit is de-energized. The controller
contains terminals to which the remote pump run indicator lamp is connected to show when the motor is
energized.
B.
DESCRIPTION.
(1)
Starter contacts connect the motor directly to the power line upon actuation of the controller.
Control circuits are isolated from the power line by a 500-volt-ampere transformer that steps down the ship's
supply to 115 volts. This low voltage can also be used to energize indicator lamps and to supply 115 volts at
60 cps to the steering panel with which the started may be used.
(2)
A remote start switch (in a steering panel), or the LOCAL-OFF-REMOTE switch on the controller
panel closes a circuit through the coil of the main line contactor. The coil closes the three line contactors and
connects the motor to the power line as long as the switch remains closed. The main line contactor also closes
the circuit to light a "run" indicator lamp.
(3)
If the motor load becomes excessive, either of three over-current thermal heaters in series with
the motor input opens the normally closed contacts in series with the coil of a control relay. This coil then
releases its spring-loaded contacts which close and energizes the overload circuit. The overload relay remains
open until it is mechanically closed by means of the RESET control. The motor remains connected to the power
line despite the over-current because continued operation is usually more important than possible damage to
the motor and hydraulic steering equipment. For this reason, an overload indication should be investigated
immediately and corrective action taken as soon as possible.
3-3192
|
||
|
||
