Brake Resistor - Mfr60 - 80 - Maytag MFR Series Service Manual

The brake resistor is on the left side of the
inverter and only on MFR60 and MFR80
models. The brake resistor prevents over
voltage on the DC bus. When the motor
is coasting it acts like a generator and can
create excessive voltage. The brake resistor
reduces spikes on the DC bus.
The value of the resistor is typically 80 watts
and 200 ohms. Be sure to allow sufficient
time between powering off and working on
the brake resistor, since it can store up to 400
volts. The white wires still have a capacitive
voltage after power is disconnected. The
power will bleed off slowly, so give it sufficient
time.
Before working on a brake resistor or an
inverter, follow the procedure for testing
inverters (See page 7-7). This must be done
anytime an inverter or brake resistor is being
worked on.
To measure the brake resistor, disconnect
the positive and PR wires from the inverter.
Check that the ohmmeter measures
zero when the two ohmmeter leads are
touched together. Test the wire leads that
were disconnected, they should measure
approximately 200 ohms. Measure from one
of the leads to a chassis ground (any bare
metal on the washer.) Set the ohmmeter to
at least a 200,000 ohm scale. The reading
should be an open circuit (infinite Ω). If there
is a low reading of anything less than 100,000
ohms it may indicate leakage in the body
of the brake resistor and a defective brake
resistor should be replaced.

BRake ReSiSTOR - MFR60 - 80

Reconnect the wires to the positive and PR
terminals. If one of these wires in incorrectly
attached to the negative terminal it will
damage the inverter and the brake resistor.
If a brake resistor is found to be damaged,
check other possible causes of the damage
including chemical or water leakage. Make
sure the jumper clip, or bridge, is installed
between the P1 and the positive terminals of
the inverter. If it is not present, install it.
For models not factory equipped with a Brake
Resistor, there is always the chance that
the inverter may record Over Voltage Codes
on the washer control board. The codes to
look for are Diagnose Failure Code 305 =
OV3, Code 304 = OV2, and Code 303 = OV1,
and they are not caused by too short of a
deceleration time, but caused by small
regenerative energy peaks, this problem can
be solved by installing a Brake Resistor.
Brake Resistor part #23004024 (type FR-ABR-
0.4K 80W / 200Ohm) should be installed
and mounted with screws to the frame at the
back of the washer near the inverter. It
needs to be wired to the inverter terminals (+)
and (PR). (See page 4-39).
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