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Building a motor controller for a Samsung brushless direct drive washer motor.

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I have recently acquired a Samsung front loading washing machine. It was working fine except for the door latch mechanism was broken so the previous owner had used huge self stick velcro straps to hold the door shut... anyway I only wanted the guts, the rest I scrapped minus the drum for a fire pit. My question is, On the motor there is the usual 3 pin(3 phase) power connector and a rotor position sensor connector. The odd thing I can't find info about anywhere, is why the hall effect sensor connector is only 4 pin instead of 5 as it is on all sensored  brushless motors I've seen? Normally the RPS/Hall sensors have 5 wires. One power, three for Hall A B C, and one ground. Neither a controller I bought nor one I built will run this motor,  however I haven't tried using either. I have the control board and the separate inverter board which the motor and sensors connect to. I want to build a controller for this motor or even better just use the factory inverter board (fed with my own control signals) to run it.. any information or advice would be much appreciated. Once I understand the sensors, making a controller will be straightforward. I could of course tear into the sensor module and see the sensors physical form and layout but I want to avoid damaging anything. Besides, opening it up to basically find it has two hall sensors instead of 3, still tells me little about how to drive the motor. The pin identifiers for the sensor cable on the board and in the very simple block diagram in the technical info pamphlet simply say, Vcc, U, V and GND. I'll include pictures of the motor,  the 4 pin sensor plugs and the factory control board. The factory motor control inverter board has (from left to right in the picture) 2 pin molex power input, 3 pin molex power output to motor, 4 pin molex hall sensor feedback, and a 3 pin molex control signal input from the main control board.. No set plans for a use yet but I'm looking forward to the design challenge. Might eventually turn it into a generator if I can't find a good use for it. Thanks for sharing your time and knowledge. -Rex- 

Modern drivers don't require hall sensors, they're sensorless, search "sensorless bldc".
The 4th wire might be because it's connected in star, not triangle.
The best you could to is to investigate the original controller. It might not be so complicated after all.
You might get more help after providing high quality pictures where part numbers are readable.

Thanks, I will update and include all part numbers.

Quick question DavidAlfa, I understand that many newer BLDC motors are sensorless, however this motors wiring diagram clearly states for the 4 pin plug to the motor, "Hall sensor." There are three power phases going into the motor as well as a 4 wire "hall sensor," cable. You mentioned what "the 4th wire might be," which is a little vague since I don't know exactly which wire you're referring to since, total, the motor has seven wires ran to it. 3 power and 4 sensor. The 4 sensor wires are #1 Vcc(power) #2 U (?) #3 V (?) and #4 ground. When you say the 4th wire my mind was thinking the sensor ground wire, but that wouldn't make sense. Thanks for any clarification you can offer. I will investigate the stator winding wiring configuration, good tip.

The model number for the Samsung front loading washer is WF42H5000A. The part number for the main control board is DC92-01803D. The part number for the inverter board (the one that actually drives the motor) is DC92-01531B. I imagine that if I could see the signal that the main board feeds the inverter I would have a good idea what signal form I need to replicate at the 3 pin input to the inverter board. Finding out the voltage of the power going into the inverter board is easy, as is would be measuring the feed power to the hall sensor. My oscilloscope can't seem to get a definitive read on the three wire drive input signal though. I see nothing resembling a PWM or other pulsed signal. In fact it's reading as just plain old AC which can't be the case.


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