Drum Motor Obiwan - Electrolux T5190LE Service Manual

DRUM MOTOR OBIWAN

23:1 HEATSINK TOO HOT
This error code is generated by the MCU for drum motor.
There is a temperature sensor (NTC) mounted on the MCU cooling flange next to the power transistors in the output
stage. If the temperature of the cooling flange gets too high (> 100°C) the error code will be set to protect the
transistors.
The cause of high cooling flange temperature can be e.g. a stiff drum in combination with intensive use and high am-
bient temperature. There may also be an error in the motor (sticking bearings or short circuit in windings, which im-
pairs the efficiency of the motor). When temperature has decreased below 85°C , the error can be reset on the
selector button.
Recommended actions:
1. Make sure the drum turns easily.
2. Check the value on the error code counter for the error code.
3. Check the last 8 MCU error codes.
4. Start a 90°C normal program with load on continuous operation and measure the temperature of the motor and
MCU.
5. Replace the defective part.
23:2 MOTOR TOO HOT
This error code is generated by the MCU for the drum motor.
The MCU monitors the motor temperature in two ways.
1. The MCU calculates the motor winding resistance by measuring current and voltage. The winding resistance can
then be converted to a temperature, since the winding resistance at 20°C and the temperature coefficient are
known. If the average value of the four latest temperature readings is higher than the maximum motor tempera-
ture (e.g. 130°C), the error code will be shown. When temperature has decreased below 130°C, the error can be
reset on the selector button.
2. The MCU monitors the input from motor over heat protection. If this input is open circuit, the error will be shown.
When input is closed again, the error can be reset on the selector button.
Possible causes:
The cause of high motor temperature can be a stiff drum, possibly in combination with intensive use and high ambi-
ent temperature. There may also be an error in the motor (sticking bearings or short circuit in windings, which impairs
the efficiency of the motor). There could also be a contact error in the connectors between the MCU and the motor or
an error in the motor cable. An error in MCU temperature measurement circuits can also occur.
Recommended actions:
• Make sure the drum turns easily.
• Check the status of motor over heat protection.
• Check the value on the error code counter for the error code.
• Check the last 8 MCU error codes.
• Measure the three phases to the phase resistors on the MCU motor connector (disconnect MCU and take the
reading in the cable connector) to make sure they are the same.
• Start a 90°C normal program with load on continuous operation and measure the temperature of the motor and
MCU.
• Replace the defective part.
Service Manual
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