Delta Electronics Inverter M42U

In order to guarantee proper long-term operation of the inverter, the following procedures must be followed used to remove and re-install the WB cover, Refer to Figure 5-1.

• Never attempt to remove the WB cover in rainy damp weather without weather protection around the inverter.

• Switch AC and DC power off and wait until LCD display turns off.

• Loosen the 4 screws on the WB front cover and remove cover.

• Use care not to contaminate the WB cover gasket and mating surfaces

After removing the WB cover, do not leave the WB uncovered for long periods of time.

Before re-installing the wiring box (WB) cover:

Periodic fan and filter cleaning is required to insure long life and reliability.

- The time period between cleanings depends on the quality of the environment.

- Under normal duty use, Delta recommends smart fans and filters be cleaned every 6 months

- For very dusty locations, it may be necessary to clean the fans and filters quarterly or monthly.

M42/36/28U models are provisioned with processor-controlled ""smart fans"" for cooling of the electronics. This section provides procedures for cleaning filters associated with these fans, and instructions for field replacement of the fans.

The fans utilized have high reliability ratings and coupled with use of processor controls provide a ""smart"" cooling system design with a long life. The system features tachometer detection of a failed fan, and generates a ""FAN-FAIL"" signal that is interfaced to the inverter control to trigger a FAN-FAIL alarm and places the inverter in a power de-rate mode as required for safe operation.

Depending upon the model, fans are installed at two locations within inverter:

• Power Module (PM) compartment (-120, -121, -122) Figures 5-10, 5-11 illustrates the fan locations. The cooling fans feature modular designs that make their removal for cleaning or replacement a simple task. As a result, the replacement of fans is also smart.

5.4.1 Power Module (PM) Fan Tray

The inverter electronics are convection cooled. The primary equipment used for this function consists of a fan tray located in a plenum within the inverter power module. The PM electronics are isolated, and heat is transferred to the plenum airflow via a large heatsink.

The PM fan tray is modular and holds four smart fans that that operate together and also provide redundancy; the inverter will operate to full power with two fans operating and will enter a power derating mode under failure of a second fan. These fans are protected by air filters at the plenum air inlet and outlet.

5.4.1.1 PM Fan Tray removal procedure

Refer to Figure 5-12 and follow the steps outlined below: 1. Remove the outlet filter assemblies on the left and right side of the PM by removing four screws on each. If filter maintenance is the goal, the two filter elements can be cleaned at this time and reassembled.