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UPS 250 and UPS 300 Uninterruptible Power Supplies Caterpillar


System Bypass Operation

Usage:

UPS 250 APZ

System Bypass

The internal bypass procedure is used when the system needs to be regulating the power to the load of the facility, but the system does not need to protect the load in case of a utility outage.

The bypass circuit powers the critical bus for one of the following reasons:

  • Maintenance is required.

  • The UPS can not maintain voltage to the load due to an overload that is sustained or a malfunction.

The bypass circuit provides a path for power directly from an alternate AC source. The control system for the UPS constantly monitors the availability of the bypass circuit (system) in order to perform a transfer.

The bypass circuit (system) consists of the following components:

  • Bypass Switch (Static)

  • Output Contactor (UPS)

  • Bypass Contactor (System)

Note: The Bypass Switch (Static) is an option.

The output contactor isolates the UPS from the load. The bypass contactor (system) works in parallel with the static bypass switch, if equipped. The static bypass switch is a solid-state device that can instantly connect the alternate AC source to the load.

Note: The static bypass switch is an option.

Operating the Maintenance Bypass

These instructions describe placing the system in bypass mode by using a key for the Maintenance Bypass. Using the key for the Maintenance Bypass to close the bypass breaker prevents the voltage from being transmitted inadvertently to the capacitor banks and possible severe damage to the UPS. These procedures are performed in an environment that can contain dangerous voltage levels. Proceed only after reading and understanding these instructions.

The system must be at a dead stop with NO power that is available when maintenance procedures are performed.

Wear a grounding strap (static) while circuit boards are being handled.

Isolating the Single Module System (SMS) for Maintenance or Repair

  • Single Module System (SMS) with a Bypass Cabinet

  • SMS without a Bypass Cabinet

SMS with a Bypass Cabinet

    Show/hide table

    Illustration 1g01796613

    User Interface Panel on the Flywheel Cabinet

    (1) Keyswitch

  1. Turn the keyswitch (1) on the Flywheel Cabinet to the "Bypass" position. Refer to Illustration 1.

  1. Remove the key from the keyswitch (1). Secure the key.

  1. Verify that the system enters the bypass mode. The "On Bypass" LED on the user interface panel will light when the system enters the bypass mode. Refer to Illustration 1.

    Show/hide table
    NOTICE

    Do not proceed with this procedure if the system does not enter the bypass mode. Equipment damage and load interruption may occur. Contact your local Caterpillar Dealership.

    Show/hide table
    NOTICE

    Make sure that the electrical path to the load of the facility is not affected when you perform the following steps. Do not allow the load of the facility to be dropped.

    Show/hide table

    Illustration 2g01797996

    Side view of the Bypass Cabinet

    (10) Bypass Switch

    (11) Output Switch

    (12) Input Switch

  1. Close the Bypass Switch (10) that is located in the Bypass Cabinet. Refer to Illustration 2.

  1. Open the Output Switch (11) that is located in the Bypass Cabinet. Refer to Illustration 2.

  1. Open the Input Switch (12) that is located in the Bypass Cabinet. Refer to Illustration 2.

  1. The system is now in the bypass mode.

    Refer to Operation and Maintenance Manual, SEBU7464, "System Startup" for information in order to return the system from the bypass mode.

SMS without a Bypass Cabinet

    Show/hide table

    Illustration 3g01796613

  1. Turn the keyswitch (1) to the "Bypass" position. Refer to Illustration 3.

  1. Remove the key from the keyswitch (1). Secure the key.

  1. Verify that the system enters the bypass mode. The "On Bypass" LED on the user interface panel will light when the system enters the bypass mode. Refer to Illustration 3.

    Show/hide table
    NOTICE

    Do not proceed with this procedure if the system does not enter the bypass mode. Equipment damage and load interruption may occur. Contact your local Caterpillar Dealership.

    Show/hide table
    NOTICE

    Make sure that the electrical path to the load of the facility is not affected when you perform the following steps. Do not allow the load of the facility to be dropped.

  1. Close the external bypass switch.

  1. Remove the electrical input to the system.

  1. Disconnect the electrical path from the output of the system in order to protect the system from electrical backfeed prevention.

  1. The system is now in the bypass mode.

    Refer to Operation and Maintenance Manual, SEBU7464, "System Startup" for information in order to return the system from the bypass mode.

Isolating the Multiple Module System (MMS) for Maintenance or Repair

  • Single Input without Switches

  • Single Input with Three Switches

  • Dual Input without Switches

  • Dual Input with Two Switches

  • Dual Input with Three Switches

Single Input without Switches

    Show/hide table

    Illustration 4g01798275

    User Interface Panel on the MMU

    (2) Keyswitch

  1. Turn the keyswitch (2) on each MMU to the "Bypass" position. Refer to Illustration 4.

  1. Remove the key from the keyswitch (2) on each MMU. Secure the keys.
    Show/hide table

    Illustration 5g00948144

  1. Hit the "Home" button on the user interface panel of each MMU. Verify that the MMU is in the "Bypassed" mode. Refer to Illustration 5.

    Show/hide table
    NOTICE

    Do not proceed with this procedure if the system does not enter the bypass mode. Equipment damage and load interruption may occur. Contact your local Caterpillar Dealership.

    Show/hide table

    Illustration 6g01796613

    User Interface Panel on the System Cabinet

    (1) Keyswitch

  1. Turn the keyswitch (1) on the System Cabinet to the "Bypass" position. Refer to Illustration 6.

  1. Remove the key from the keyswitch (1) on the System Cabinet. Secure the key.

    Show/hide table
    NOTICE

    Make sure that the electrical path to the load of the facility is not affected when you perform the following steps. Do not allow the load of the facility to be dropped.

  1. Close the external bypass switch.

  1. Remove the electrical input to the system.

  1. Disconnect the electrical path from the output of the system in order to protect the system from electrical backfeed prevention.

  1. The system is now in the bypass mode.

    Refer to Operation and Maintenance Manual, SEBU7464, "System Startup" for information in order to return the system from the bypass mode.

Single Input with Three Switches

    Show/hide table

    Illustration 7g01796613

    User Interface Panel on the System Cabinet

    (1) Keyswitch

  1. Turn the keyswitch (1) on the System Cabinet to the "Bypass" position. Refer to Illustration 7.

  1. Remove the key from the keyswitch (1) on the System Cabinet. Secure the key.
    Show/hide table

    Illustration 8g01798275

    User Interface Panel on the MMU

    (2) Keyswitch

  1. Turn the keyswitch (2) on each MMU to the "Bypass" position. Refer to Illustration 8.

  1. Remove the key from the keyswitch (2) on each MMU. Secure the keys.
    Show/hide table

    Illustration 9g00948144

  1. Hit the "Home" button on the user interface panel of each MMU. Verify that the MMU is in the "Bypassed" mode. Refer to Illustration 13.

    Show/hide table
    NOTICE

    Do not proceed with this procedure if the system does not enter the bypass mode. Equipment damage and load interruption may occur. Contact your local Caterpillar Dealership.

    Show/hide table

    Illustration 10g01797234

    (3) Maintenance Bypass Switch

    (8) Key

  1. Insert the key (8) into the Maintenance Bypass Switch (3) in the Input/Output Cabinet. Refer to Illustration 10.

    Note: Although the keys are similar in appearance, the key (8) for the Maintenance Bypass Switch (3) is different from the key for the user interface panel.

  1. Turn the key (8) for the Maintenance Bypass Switch counterclockwise.

    Show/hide table
    NOTICE

    Make sure that the electrical path to the load of the facility is not affected when you perform the following steps. Do not allow the load of the facility to be dropped.

    Show/hide table

    Illustration 11g01802293

    Input/Output Cabinet

    (3) Maintenance Bypass Switch

    (4) Output Isolation Switch

    (5) Input Isolation Switch

  1. Close the Maintenance Bypass Switch (3) that is located in the Input/Output Cabinet. Refer to Illustration 11.

  1. Open the Output Isolation Switch (4) that is located in the Input/Output Cabinet. Refer to Illustration 11.

  1. Open the Input Isolation Switch (5) that is located in the Input/Output Cabinet. Refer to Illustration 11.

  1. Install safety locks by using the tabs for lockout on the front of the switches.

  1. Allow the capacitor banks to bleed down for approximately 5 minutes in order to dissipate any residual energy that may exist in the following components: the bus, the armature leads and the fuses.

  1. The system is now in the bypass mode.

    Refer to Operation and Maintenance Manual, SEBU7464, "System Startup" for information in order to return the system from the bypass mode.

Dual Input without Switches

    Show/hide table

    Illustration 12g01798275

    User Interface Panel on the MMU

    (2) Keyswitch

  1. Turn the keyswitch (2) on each MMU to the "Bypass" position. Refer to Illustration 12.

  1. Remove the key from the keyswitch (2) on each MMU. Secure the keys.
    Show/hide table

    Illustration 13g00948144

  1. Hit the "Home" button on the user interface panel of each MMU. Verify that the MMU is in the "Bypassed" mode. Refer to Illustration 13.

    Show/hide table
    NOTICE

    Do not proceed with this procedure if the system does not enter the bypass mode. Equipment damage and load interruption may occur. Contact your local Caterpillar Dealership.

    Show/hide table

    Illustration 14g01796613

    User Interface Panel on the System Cabinet

    (1) Keyswitch

  1. Turn the keyswitch (1) on the System Cabinet to the Bypass position. Refer to Illustration 14.

  1. Remove the key from the keyswitch (1). Secure the key.

    Show/hide table
    NOTICE

    Make sure that the electrical path to the load of the facility is not affected when you perform the following steps. Do not allow the load of the facility to be dropped.

  1. Close the external maintenance bypass switch.

  1. Remove the electrical input to the system.

  1. Disconnect the electrical path from the output of the system in order to protect the system for electrical backfeed prevention.

  1. The system is now in the bypass mode.

    Refer to Operation and Maintenance Manual, SEBU7464, "System Startup" for information in order to return the system from the bypass mode.

Dual Input with Two Switches

    Show/hide table

    Illustration 15g01798275

    User Interface Panel on the MMU

    (2) Keyswitch

  1. Turn the keyswitch (2) on each MMU to the "Bypass" position. Refer to Illustration 15.

  1. Remove the key from the keyswitch (2) on each MMU. Secure the keys.
    Show/hide table

    Illustration 16g00948144

  1. Hit the "Home" button on the user interface panel of each MMU. Verify that the MMU is in the "Bypassed" mode. Refer to Illustration 16.

    Show/hide table
    NOTICE

    Do not proceed with this procedure if the system does not enter the bypass mode. Equipment damage and load interruption may occur. Contact your local Caterpillar Dealership.

    Show/hide table

    Illustration 17g01796613

    User Interface Panel on the System Cabinet

    (1) Keyswitch

  1. Turn the keyswitch (1) on the System Cabinet to the "Bypass" position. Refer to Illustration 17.

  1. Remove the key from the keyswitch (1) on the System Cabinet. Secure the key.

    Show/hide table
    NOTICE

    Make sure that the electrical path to the load of the facility is not affected when you perform the following steps. Do not allow the load of the facility to be dropped.

    Show/hide table

    Illustration 18g01797234

    (3) Maintenance Bypass Switch

    (8) Key

  1. Insert the key (8) into the Maintenance Bypass Switch (3) in the Input/Output Cabinet. Refer to Illustration 18.

    Note: Although the keys are similar in appearance, the key (8) for the Maintenance Bypass Switch (3) is different from the key for the user interface panel.

  1. Turn the key (8) for the Maintenance Bypass Switch counterclockwise.
    Show/hide table

    Illustration 19g01798373

    Input/Output Cabinet

    (3) Maintenance Bypass Switch

    (4) Output Isolation Switch

  1. Close the Maintenance Bypass Switch (3) that is located in the Input/Output Cabinet. Refer to Illustration 19.

  1. Open the Output Isolation Switch (4) that is located in the Input/Output Cabinet. Refer to Illustration 19.

  1. Install safety locks by using the tabs for lockout on the front of the switches.

  1. Remove utility power from the input bus for the system.

  1. Allow the capacitor banks to bleed down for approximately 5 minutes in order to dissipate any residual energy that may exist in the following components: the bus, the armature leads and the fuses.

  1. The system is now in the bypass mode.

    Refer to Operation and Maintenance Manual, SEBU7464, "System Startup" for information in order to return the system from the bypass mode.

Dual Input with Three Switches

    Show/hide table

    Illustration 20g01798275

    User Interface Panel on the MMU

    (2) Keyswitch

  1. Turn the keyswitch (2) on each MMU to the "Bypass" position. Refer to Illustration 20.

  1. Remove the key from the keyswitch (2) on each MMU. Secure the keys.
    Show/hide table

    Illustration 21g00948144

  1. Hit the "Home" button on the user interface panel of each MMU. Verify that the MMU is in the "Bypassed" mode. Refer to Illustration 21.

    Show/hide table
    NOTICE

    Do not proceed with this procedure if the system does not enter the bypass mode. Equipment damage and load interruption may occur. Contact your local Caterpillar Dealership.

    Show/hide table

    Illustration 22g01796613

    User Interface Panel on the System Cabinet

    (1) Keyswitch

  1. Turn the keyswitch (1) on the System Cabinet to the "Bypass" position. Refer to Illustration 22.

  1. Remove the key from the keyswitch (1) on the System Cabinet. Secure the key.

    Show/hide table
    NOTICE

    Make sure that the electrical path to the load of the facility is not affected when you perform the following steps. Do not allow the load of the facility to be dropped.

    Show/hide table

    Illustration 23g01797234

    (3) Maintenance Bypass Switch

    (8) Key

  1. Insert the key (8) into the Maintenance Bypass Switch (3) in the Input/Output Cabinet. Refer to Illustration 23.

    Note: Although the keys are similar in appearance, the key (8) for the Maintenance Bypass Switch (3) is different from the key for the user interface panel.

  1. Turn the key (8) for the Maintenance Bypass Switch counterclockwise.
    Show/hide table

    Illustration 24g01798373

    Input/Output Cabinet

    (3) Maintenance Bypass Switch

    (4) Output Isolation Switch

    (5) Input Isolation Switch

  1. Close the Maintenance Bypass Switch (3) that is located in the Input/Output Cabinet. Refer to Illustration 24.

  1. Open the Output Isolation Switch (4) that is located in the Input/Output Cabinet. Refer to Illustration 24.

  1. Open the Input Isolation Switch (5) that is located in the Input/Output Cabinet. Refer to Illustration 24.

  1. Install safety locks by using the tabs for lockout on the front of the switches.

  1. Remove utility power from the input bus for the system.

  1. Allow the capacitor banks to bleed down for approximately 5 minutes in order to dissipate any residual energy that may exist in the following components: the bus, the armature leads and the fuses.

  1. The system is now in the bypass mode.

    Refer to Operation and Maintenance Manual, SEBU7464, "System Startup" for information in order to return the system from the bypass mode.

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