• SIGNA MR355 / SIGNA MR360
  • Service Manual
  • 5856356-3EN Revision 5.0
  • Basic Service Documentation. Copyright General Electric Company.
  • Object ID: 00000018WIA30A73F20GYZ
  • Topic ID: id_13106219 Version: 1.3
  • Date: Jul 5, 2019 11:49:11 PM

25kVA PDU Module

IMPORTANT SAFETY INSTRUCTIONS

SAVE THESE INSTRUCTIONS – This manual contains important instruction for 1.5T 25kVA Power Distribution Unit (PDU) that must be followed during installation, operation, and maintenance.

INTRODUCTION

General Description

The Power Distribution Unit (PDU) distributes power to various components of a General Electric Medical Systems MRI system. Three phase input voltage is selectable among six levels: 200/208/380/400/415/480 VAC. Rated frequency is 50/60 Hz. Power rating is 25 KVA continuous, 30 KVA instantaneous. The PDU mounts in a System Cabinet Rack.

Figure 1. Power Distribution Unit

Scope

This manual describes procedures for installation, basic operation of the Power Distribution Unit, simple diagnosis/isolation, and schematics of the PDU. Replacement of FRU parts are described in 'Replacement' tab CD-ROM manual.

SPECIFICATIONS

Specifications subject to revision without notice

Electrical Specifications

Power Rating:25 KVA Continuous; 30 KVA Instantaneous

Input Voltage:200/208/380/400/415/480 VAC Delta, User Selectable

Note:

Factory wired for 480VAC Delta

Output Voltage:208/120 VAC WYE

Overload Protection:Main Input Circuit Breaker with adjustable trip settings; Output distribution circuit breakers

Night Mode:Save Power when System is standby mode

Installation and Operation

Installation

Input Voltage Selection

Before connecting the input power cables, determine the nominal value of the input voltage. The PDU allows for nominal input voltages of 200, 208, 380, 400, 415, or 480 VAC (three phase). Input voltage selection is accomplished as follows:

  1. On the Main Disconnect Panel (MDP), turn off the PDU circuit breaker, lock and tag appropriately.

  2. Using a voltmeter or other voltage indicating device at the Primary Test Jack, check to be sure that no voltage is being applied to the input of the PDU.

  3. Remove the front cover of System Cabinet and the lower cover of PDU.

    Figure 2 shows the Input Voltage Selection terminal block. Figure 3 shows how to remove/install terminal cable. For each of the three phases, be sure the wire is connected to the proper terminal for the actual input voltage at the site and that the terminal screw is tight to make a good connection.

  4. Remove the cover panel from the front panel of the PDU marked “MAIN INPUT CIRCUIT BREAKER CURRENT ADJUST”. See Figure 4.

  5. The overload and short circuit trip settings for the Main Input Circuit Breaker must be set to the correct values corresponding to the input voltage.

    1. Remove the small cover plate under the Main Input Circuit Breaker which is held in place by four screws and lift open the transparent plastic cover on the lower portion of the circuit breaker to give access to the dip switches controlling the circuit breaker operation.

    2. Figure 5 shows the position of the dip switches for each input voltage selection. Set the dip SW to the correct value corresponding to the input voltage.

Figure 2. INPUT VOLTAGE SELECT TERMINAL BLOCK
Figure 3. How to remove/install terminal cable
Table 1. maximum full-load input currents
Input Voltage200V208 V380 to 480 V
Maximum input current80A76A40A
Figure 4. Cover for Overload and short circuit trip dip SW
Figure 5. CIRCUIT BREAKER DIP SWITCH SETTINGS

Operation

Main Input Circuit Breaker

The Main Input Circuit Breaker operating handle has three positions:

  • OFF (Horizontal)

  • ON (vertical)

  • TRIPPED (slightly to the left of vertical). If the Main Input Circuit Breaker has been tripped, it is necessary to move the handle to the OFF position to reset it before turning it ON.

The Main Input Circuit Breaker may be locked in the OFF position. By pressing on the small triangle on the operating handle, the lockout tab is made accessible to a padlock.

Power Off

The Power OFF button at the top of the front panel, when pressed, will immediately trip the Main Input Circuit Breaker, interrupting all power to the load.

EMO Reset

The EMO Reset button immediately to the right of the Power Off push button will enable the Emergency Stop circuit.

Input / Output Voltage Test Points

The voltages at these points are measured by a factor of 1:1 from the actual voltage at the terminal blocks.

Figure 6. FRONT PANEL COMPONENT LOCATIONS

Troubleshooting

Check System Error Log or Cabinet Monitor Error Log.

Table 2. PDU FAULT SYMPTOMS AND POSSIBLE CAUSES
SymptomPossible Cause
E-Off not working or E-Stop contactor won't pick up.

  • Cabinet Monitor Working properly?

  • A Connector may be loose in the Emergency loop (Emergency loop diagram please refer to page23 in Media File3 of sys Diagrams-> System Block Diagram)

  • PDU control board may have some issue