Maytag Commercial MYR20, Service Manual

Page: 75 / 88

5-5
Before servicing or replacing the VFD,
(Variable Frequency Drive), remove power to
the washer and wait a minimum of 10 minutes
to allow potential stored voltage to dissipate.
Always check DC voltage at Terminals P/+
and N/- to insure no voltage is present before
servicing.
If an F11 Drive Error is recorded, first
determine if the fault is a Communication
Error or a Motor Error. Test Drive operation in
Diagnostic Main Control Test by running Motor
Check Tumble test. (Refer to Diagnostic Tests)
If the fault is a Communication Error check
supply voltage and Contactor. Confirm voltage
at VFD. If fault is Motor Error, check drive belt
and check basket rotation for restriction.
If necessary confirmation of DC Bus voltage
can be measured at Positive (P/+) and
Negative (N/-) terminals. Formula to determine
DC Bus voltage is 1.414 X Supply Voltage.
(Example = 1.414x240VAC = 339VDC).