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High voltage may be present. Work on this equipment must be performed by authorized trained personnel. Failure to use appropriate Personal Protective Equipment (PPE) could result in serious injury or death. Personnel must be wearing PPE that meets regulatory requirements to protect the body for the work that is being performed. |
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High voltage may be present. The power source must be disconnected before working on the equipment. Failure to disconnect the power source could result in injury or death. Verify that the equipment is not energized before performing any maintenance. This work must be performed by trained personnel with correct tools and procedures. Bodily contact with electrical potential will cause personal injury or death. |
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| Illustration 1 | g02324673 |
Ensure that all lockout/tagout procedures for the site are followed. Illustration 1 shows some typical items used to lock or tag the power sources. These items ensure that power is not applied while the equipment is being serviced.
Hot Swap Option for Parallel UPS Units
In parallel applications, an external bypass is required to provide a common point for output of the UPS. The external bypass provides a mode of operation to maintain the system without interruption to the load.
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| Illustration 2 | g02357476 |
Parallel UPS With Common AC inputs, Normal AC inputs, and Bypass AC inputs | |
Parallel UPS Connections Between Cabinets
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| Illustration 3 | g02384099 |
(A) Connection cables | |
The connections shown in Illustration 3 are made on the UPOZ board that is marked "18" and the MUSI board that is marked "22". Refer to the "Component Location" section of this publication for board location.
The purpose of the connection is to make a loop. The XM137 connector is located on the UPOZ board of the UPS unit. This connector must be connected to XM136 connector that is on the UPOZ board of the next UPS unit. The connection scheme must be followed until the last board is connected to the first board.
Connections Between UPS Cabinets and the Remote External Bypass
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| Illustration 4 | g02384301 |
Two parallel UPS unit connections | |
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| Illustration 5 | g02384302 |
Three parallel UPS unit connections | |
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| Illustration 6 | g02384304 |
Four parallel UPS unit connections | |
Illustrations 4 through 6 provide examples of parallel UPS cable connections.
The XM5, XM6, and XM7 connectors that are on the MUSI board are used to transmit signals.
The XM10, XM11, and XM12 connectors that are on the MUSI board are used to receive signals.
The XM5 connector is associated with the XM10 connector for communication with one UPS unit. Similarly, the XM6 connector is associated with XM11 connector for communication with a second UPS unit. The XM7 connector is associated with the XM12 connector for communication with a third UPS unit.
Note: Outside the cabinets, group the UPOZ cables and the MUSI cables with the auxiliary connections. Keep the control wires separated from the power cables.