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| Illustration 1 | g03800837 |
Lower MOV surge protector
Upper MOV surge protector
MOV surge protector locations
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| Illustration 2 | g01274927 |
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MOV surge protector wiring | |
The metal oxide varistor (MOV) surge protector (1) is located on the back panel at the bottom of the MMS cabinet. In the post 2.4 hardware, the system cabinet has another MOV (2). The MOV (2) is connected to the ceiling of the system cabinet. Refer to Illustration 1 for the locations.
The MOV surge protector is connected to the 3-phase input power from the multiple module units. The MOV surge protector monitors the incoming voltage for spikes. When a spike is detected, resistance in the MOV is overcome and the extra voltage is diverted ground.
There are three LEDs on the front of each MOV. There is one LED for each phase in order to indicate proper operation of the MOV.
Note: If the MOV surge protector fails, do not restart the machine. Contact the technical communicator for further assistance.
Removal Procedure for the Lower MOV
Refer to Systems Operation, Testing and Adjusting, UENR3954, "Internal Component Preremoval Steps (MMS System Cabinet)" in order to shut down the system and gain access to internal components.
- Disconnect the wires that lead from the back of the MOV surge protector (1). There are three black wires. The wires have a labeling to the location of the wire. Verify the labeling of the wire for subsequent installation.
- Remove the four bolts that secure the surge protector bracket to the rear of the cabinet.
- Remove the nut that attaches the MOV (1) to the bracket.
- Remove the MOV (1) from the bracket.
Installation Procedure for the Lower MOV
- Thread the wires coming from the back of the MOV through the bracket.
- Thread the large nut onto the wires.
- Screw the nut onto the threaded portion of the MOV.
- Attach the MOV bracket to the back of the cabinet using four bolts.
- Tighten the bolts to
11.3 N·m (100 lb in) . - Connect the wires coming from the back of the MOV to the proper locations in the cabinet.
Removal Procedure for the Upper MOV
Refer to Systems Operation, Testing and Adjusting, UENR3954, "Internal Component Preremoval Steps (MMS System Cabinet)" in order to shut down the system and gain access to internal components.
- Disconnect the wires that lead from the back of the MOV surge protector (2). There are three black wires. The wires have a labeling to the location of the wire. Verify the labeling of the wire for subsequent installation.
- Remove the nut that attaches the MOV (2) to the bracket.
- Remove the MOV (2) from the bracket.
Installation Procedure for the Upper MOV
- Thread the wires coming from the back of the MOV through the bracket.
- Thread the large nut onto the wires.
- Screw the nut onto the threaded portion of the MOV.
- Connect the wires coming from the back of the MOV to the proper locations in the cabinet.