• Optima MR450w BASE 1.5T System Service Methods
  • 5690012-2EN Revision 3
  • Object ID: 00000018WIA306D4E20GYZ
  • Topic ID: id_13107370 Version: 3.6
  • Date: Jan 14, 2021 3:35:43 PM

Power On Sequencing

Prerequisites

Table 1. Personnel requirements
Required personsPreliminary requirementsProcedureFinalization
1Not Applicable15-60 minutesNot Applicable
Table 2. Tools and test equipment
ItemQuantityEffectivityPart numberManufacturer
Digital Volt Meter (DVM)1---
Table 3. Safety

About this task

The Power On Sequence is slightly different with Discovery/Optima systems. The Main Disconnect Panel (MDP) and the Heat Exchange Cabinet (HEC) are required to power the Cryogen Cooler Compressor (CRY) and the Magnet Coldhead (See Illustration below). This document provides the installation checklist for powering on the system, and an overview description of the MDP, HEC, CRY, and the Power Distribution Unit (PDU).
Figure 1. Power Flow Block Diagram
The checklist items covered here should be done prior to starting the Installation Calibration Wizard. This checklist is to confirm proper setup.

Main Components

The following provides an overview of each main component in this sequence:

  • Heat Exchange Cabinet (HEC)

    The HEC contains a control power transformer that is set to 480 Vac. For sites with a different customer-supplied voltage, the control power transformer wiring switch will need to be changed. The HEC contains the power interface to the Cryogen Cooler Compressor (CRY). In order to power the coldhead after magnet delivery, the power cabling will need to be wired from the MDP to the HEC, and from the HEC to the Cryo Cooler. The power cable between the MDP and the HEC will be customer supplied and installed.

  • Cryogen Cooler Compressor (CRY)

    The CRY receives power from the HEC. The coldhead power cable will need to be installed to power the coldhead.

  • Power Distribution Unit (PDU)

    The PDU is setup for 480 Vac by default. For sites with a different customer supplied voltage, the power wiring will need to be changed. The power cable between the MDP and the PDU will be customer supplied and installed. The overload and short-circuit settings are dependent upon the voltage input and may need to be changed if the input voltage is changed. Not all PDUs need overload and short circuit current settings adjusted. Refer to installed PDU's manual to determine adjustment requirements.

  • Power & Gradient Cabinet (PGR)

    The PGR houses the eXtreme Gradient Amplifiers (XGA or XG2), eXtreme Power Supplies (XPS or XPS2) and the PDU. The gradient cable connections to the XGA or XG2 for each axis can be accessed here.

List of Procedures

This document includes the following Power On Checklist procedures:

  • Confirm the Heat Exchange Cabinet (HEC) Voltage Selection
  • Confirm Internal Power Wiring to the Power Distribution Unit (PDU)
  • Confirm Overload and Short Circuit Trip Settings for the PDU Input Circuit Breaker (Pre-DVapps PDU 5140621)
  • Check the gradient cable connection at the PGR

Confirm Emergency Off functionality (E-Off)

About this task

To shut down the host PC and ICNs:

Procedure

  1. Launch the Service Desktop Manager.
  2. Click the Tools button and choose System Shutdown from the menu.
    Note: Shutting down the system as indicated above also shuts down the ICNs.
    Figure 2. Service tools menu

Emergency off

About this task

The AC power for the Magnet Monitor is not controlled by the Emergency Off button.

Procedure

  1. Turn off the breakers for the Host, ICN (Recon), and 48V Gradient Control if you are testing more E-Off buttons.
    Note: If you do not turn off the breakers, the Host and ICNs will restart when power is enabled again, and you will need to wait for them to boot before you can test the additional E-Off buttons.
    Figure 3. Host, ICN, and 48V Gradient Control breakers
  2. Press one of the E-Off buttons, which will look similar to the examples in the figure below. The location of the buttons was specified by the customer, and generally they are located on the wall next to the computer equipment or next to the MR magnet room doors.
    Figure 4. Example E-Off buttons
  3. Make sure that power was removed from the PDU by looking at the PDU phase indicator lights and examining the input voltage test points (as the lights may have burned out).
    Figure 5. PDU phase indicator lights - on with power (left) and off with no power (right)
    1Phase indicator lights
    2Input voltage
  4. Make sure that power was removed from the Heat Exchange Cabinet (HEC). The display lights on the Programmable Logic Controller (PLC) Signal Box and Variable Frequency Drive (VFD) will be off (they are green when on).
    Figure 6. PLC Signal Box (left) and VFD (right)
  5. Repeat Step 1 through Step 4 for all the other E-Off buttons, including the SYSTEM OFF button on the Main Disconnect Panel (MDP).
    Figure 7. SYSTEM OFF button on the MDP
  6. Turn on the breakers for the Host, ICN (Recon), and 48V Gradient Control when you have tested all the E-Off buttons.
    Figure 8. Host, ICN, and 48V Gradient Control breakers

Finalizing Emergency Off functionality (E-Off) check

About this task

Procedure

  1. On the System MDP, press the SYSTEM ON button.
    Figure 9. MDP controls
    1PDU Breaker
    2System On
  2. Reset the PDU breaker.
  3. On the PDU, press the EMO RESET button.
    Figure 10. PDU EMO RESET button
  4. Run the Doing a check scan procedure to make sure the system is functioning normally.

Confirm Heat Exchange Cabinet (HEC) Voltage Selection

Procedure

  1. Follow the table below to confirm the transformer switch is in the proper position. See Figure 11.
    Table 4. Transformer Switch Position
    Incoming Voltage HEC Switch Position
    480, 415, or 400 VacUp
    380 VacDown
    Note:

    The UP position is labelled "480V~" and the DOWN position is labelled "380V~".

  2. If the switch is not in the correct position, change the switch position.
    Figure 11. HEC Voltage Selection Switch

Confirm Internal Power Wiring to the Power Distribution Unit (PDU)

About this task

The PDU is shipped with the default voltage setting of 480 Vac.

Procedure

  1. Remove the small cover plate which is held in place by two screws.
    Figure 12. Input Voltage Select Small Cover (79 kVA)
    Figure 13. Input Voltage Select Small Cover (73 kVA)
  2. Confirm that the three Input Voltage Selection Terminal Blocks are wired in the correct configuration. If the power connections are not configured properly, ensure that the proper personnel correct the wiring. See PDU Operation and Maintenance Manual for additional details.
    Figure 14. Input Voltage Selection - Set at 480 Vac

Confirm Overload and Short Circuit Trip Settings for the PDU Input Circuit Breaker

About this task

Note: Overload and Short Circuit Trip Settings only apply to pre-DVapps PDU 5140621. The overload and short circuit trip settings for the Input Circuit Breaker must be set to the correct values corresponding to the input voltage.

Procedure

  1. Remove the small cover plate under the main circuit breaker.
  2. Lift open the transparent plastic cover on the lower portion of the circuit breaker to access the DIP switches controlling the circuit breaker.
  3. Confirm that the switches immediately under the letter “L” are configured correctly. The illustration below shows the position of the DIP switches for each input voltage.
    Figure 15. Circuit Breaker DIP Switch Settings (Black=ON / White=OFF)
  4. If the DIP switches are not configured correctly, ensure that proper personnel correct the DIP switches settings per the PDU Operation and Maintenance Manual

Check Gradient Cable Connection at PGR

Procedure

  1. Check the gradient cable connections at the PGR to confirm no shorts between two axis or load shorts to ground.
    Note:

    Complete this section BEFORE applying power to the PGR.

  2. Ensure the following checks between points are low resistance (< 5 ohms) with a DVM in the following table.
    Table 5. PGR Gradient Coil Load Check — Ensure Same Coil
    From To Expected Value
    X-Axis XGA(XG2) – J17X-Axis XGA(XG2) – J18< 5 ohms
    Y-Axis XGA(XG2) – J17Y-Axis XGA(XG2) – J18< 5 ohms
    Z-Axis XGA(XG2) – J17Z-Axis XGA(XG2) – J18< 5 ohms
  3. Ensure the following checks between points are open (> 10 k ohms) with a DVM in the following table.
    Table 6. PGR Gradient Coil Load Check — No Shorts
    From To Expected Value
    X-Axis XGA(XG2) – J17Y-Axis XGA(XG2) – J17> 10 k ohms
    X-Axis XGA(XG2) – J17Z-Axis XGA(XG2) – J17> 10 k ohms
    Y-Axis XGA(XG2) – J17Z-Axis XGA(XG2) – J17> 10 k ohms
    X-Axis XGA(XG2) – J17Ground> 10 k ohms
    Y-Axis XGA(XG2) – J17Ground> 10 k ohms
    Z-Axis XGA(XG2) – J17Ground> 10 k ohms
  4. If any of the Table 4 and Table 5 checks fail, review the installation instructions for gradient cable connections between the magnet and the PGR prior to applying power to the system.
    Note:

    This check does not ensure X, Y and Z gradient load coils are connected to the corresponding gradient amplifier.

Finalization

Finalization

Select Installation Calibration Wizard checklist items that were confirmed as completed.