Testing Inverters - Maytag MFR Series Service Manual

DANGER
Electrical Shock Hazard
Only authorized technicians should
perform diagnostic voltage
measurements.
After performing voltage
measurements, disconnect power
before servicing.
Failure to follow these instructions
can result in death or electrical
shock.
When performing live voltage measurements, you must do the following:
Verify the controls are in the off position so that the appliance does not start when energized.
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Allow enough space to perform the voltage measurements without obstructions.
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Keep other people a safe distance away from the appliance to prevent potential injury.
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Always use the proper testing equipment.
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After voltage measurements, always disconnect power before servicing.
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MFR30 - 80 use Mitsubishi inverters and have
208-240VAC supplied from the contactor
when a washer cycle is started or running.
The contactor is connected to terminals
"L1" & "L2" of the inverter. MFR18 & 25
use AKO inverters and have a 110-120VAC
power supply at "L1" & N. Both inverter
types convert single phase input voltage to
three phase power to drive the motor. Erratic
voltages, low voltage or high voltage will
cause inverter fault codes and / or possible
damage to the inverter drive and associated
components.

TeSTinG inveRTeRS

Voltage Measurement Safety Information
7-7
WARNING
WARNING
Electrical Shock Hazard
Disconnect power before servicing.
Replace all parts and panels before
operating.
Failure to do so can result in death or
electrical shock.
To test an inverter,
1. Unplug washer or disconnect power.
2. Wait 10 minutes before attempting any
further steps.
3. Remove the back panel (See page 4-28)
4. Make sure to use a DC volt meter for the
following test because an AC volt meter will
register zero and there could be too much
voltage present.
nOTe: First, test meter at another source
to make sure the meter can measure DC
voltage.