Product Manual B

4. Operation - PowerCommand 1.1 3-2018

NOTICE

Diesel engines only: Cummins Inc. recommends the installation of an air

intake shutoff device or a similar safety device to minimize the risk of

overspeeding where an engine will be operated in a combustible

environment.

NOTICE

Long periods of idling (more than ten minutes) can damage an engine. Do

not idle the engine for excessively long periods.

Sequence of Operation

NOTICE

The following sequences are based on an approximate time duration. Your

generator set may vary slightly from the timing diagrams in this manual. All

referenced times are based on default control settings. The following

sequences are applicable to generator sets connected to an RA series

transfer switch.

Power Outage Sequence

The sequence of operation after a power outage (when the generator set is in

Auto Mode) is as follows:

1. In normal operation, the utility power is running to the transfer switch and

then to the building load, and the generator set is off.

2. The utility power turns off (power outage).

3. One second after the power outage, the transfer switch sends the

command to the generator set to start.

4. If the ambient temperature is below 20 °F/-6.7 °C, the generator set will

idle at 800 rpm for up to 2 minutes to allow sufficient turbo lubrication.

• The set points are 20 °F/-6.7 °C and below, ramping linearly from 0

sec (20 °F/-6.7 °C) to 2 minutes (-40 °F/-40 °C) and held constant at

2 minutes if below -40 °F/-40 ° C.

FIGURE 17. COLD START IDLE ACTIVE