• Topic ID: id_16158067
  • Version: 2.0
  • Date: Nov 7, 2019 8:55:33 PM

Equipment Service - NGPDU

This procedure supports the following NGPDU:

  • NGPDU-6, -60, -61

  • NGPDU-7, -70, -71

Figure 1. NGPDU Front & Rear (exposed view)

The PDU must be de-energized prior to performing work on it. 100 Kilowatts of power exists in the PDU at various periods of time. Therefore, consider all points in the PDU as hazardous.

Service Exceptions: The PDU contains voltages above 240 Volts. Read and heed Warning prior to performing live circuit Volt measurements.

Figure 2. Arc Flash Hazard

Notice Image
  • danger
  • Hazard Level 2
  • Arc flash
  • when performing live circuit volt measurements all precautions must be followed to avoid death or injury. Individuals must have current training in LOTO, Arc Flash, and electrical safety. It is mandatory to wear the proper Personal Protective Equipment as outlined in this training.Ensure all secondary protective covers on the PDU are fully installed BEFORE the PDU is energized.
  • PPE Warning

1 Electrical

1.1 Potential Hazards

  • Axial drive power for gantry rotation (AC)

  • High voltage DC for X-ray generation (floating DC)

  • Distributed console, table and gantry power (AC)

1.2 Hazard Awareness Indicators

Two small power lamps are visible on the front cover. When illuminated, one lamp indicates power is present within the PDU. Another lamp is also a switch named “Gantry Switch”, which is used to control AC 120 V power for CT Gantry. See Figure 3

Figure 3. PDU Power Lamp

1.3 Protected Service Outlets

The service outlet is protected by a circuit breaker. The outlet is located on the Terminal panel. See Figure 1.

1.4 Circuit Breakers and Switches

CIRCUIT BREAKERS

There are some circuit breakers in the NGPDU used to protect various parts of the system. See Figure 4.

CB2 - Axial Drive

CB3 - UPS Power Supplier

CB5 - CT Gantry Rotating Loads

CB7 - Operator Console Loads

CB8 - PET Gantry

CB9 - NGPDU Control Power Supply

CB10 - NGPDU Control Power Supply

Figure 4. PDU Circuit Breakers for NGPDU

Figure 5. SWITCH 2 MNL_HVDC

Notice Image
  • notice
  • The SW2-MNL HVDC switch is set to the Auto OFF position from the factory and must always remain in the Auto OFF position.
  • There is no service procedure which requires the use of this switch.
  • Do not tamper with this switch for any reason, including troubleshooting, unless explicitly requested by CT Engineering.

2 Mechanical

The PDU’s top cover is not hinged. To access the top of the PDU, loosen the top cover front retaining screw, then lift and remove the PDU top cover.