Alpha Technologies VMX Series - Manual (Page 51)

51 017-940-B0-001, Rev. A
6.0 VMX Power Supply Maintenance, continued
6.4 Check Battery Charger Voltage
The advanced three-stage charging features of the VMX Power Supply are completely self-
monitoring. During normal power supply operations, the power supply continuously verifi es
the operating condition of the battery charger. If, for any reason, the battery charger fails, a
Charger Fail alarm displays on the Smart Display. No operator voltage checks are required.
6.5 Check Battery Terminals and Connecting Wires
Check each battery terminal and connection. Verify the posts are clean and the crimped
connectors are tight. Terminal connectors should be torqued in accordance with the battery
manufacturer's recommendation. If there is an in-line fuse in the battery cable, check the fuse
holder and fuse. Verify the terminals are properly protected with an approved battery terminal
corrosion inhibitor such as NCP-2. Record date of maintenance in the maintenance log.
6.6 Check Output Voltage
Measure the AC output voltage at the VMX Power Supply Transformer Module’s Output test
points using a true RMS AC voltmeter. Only use a True RMS meter, as other meters may not
give a correct reading.
Output voltages should appear within ±5% of rated output at a nominal line input.
Record the voltages in the maintenance log. Output voltages can also be observed by using
the Smart Display.
Whenever the battery breaker is turned off, or the batteries are not connected, the VMX Power Supply
automatically reports a No Batteries alarm. This is normal, and is a built in safety feature. The unit does not
attempt inverter operations, either standby or test, during a No Battery alarm.
NOTE:
Setting Low (-5%) High (+5%)
87Vac 82.65Vac 91.35Vac
63Vac 59.85Vac 66.15Vac
48Vac 45.60Vac 50.40Vac
6.7 Check Output Current
With the VMX Power Supply in normal operating mode, observe the Output current values
indicated by the Smart Display. The values of output current will be dependent on the total
amount of load connected to each output of the power supply. Record the current in the
maintenance log.