I've got the following DC motor that I'm trying to run with a little PWM generator that I purchased, but what I've tried hasn't worked, and I can't find any useful documentation for the motor:


Model: YY225H310B

DC 310 V 0.65 A

There is a little cover on the motor that I looked under, and the following image depicts what is inside:

Circuitry of the motor itself

The motor is out of a Mila air purifier manufactured in 2020.

It has five wires: red, black, white, yellow, and blue. I'm fairly certain that the red and black ones are for powering the motor (310 V), and the other three are related to controlling its speed. Based on my findings regarding other DC motors, I thought that maybe blue = PWM, yellow = tach, and white = ground, but it doesn't seem to work when I hook it up.

I connected the blue wire to my PWM generator output (and white as ground), and I've tried 3.7 V and 10 V as my V+/V-, both at 0 through 100 kHz, but nothing moves the motor. Before I try moving the wires around (maybe yellow is PWM?), I wanted to see if anyone knowledable could help shine some light on the subject. Note that the red and black wires were connected to a 170 V supply (this is the DC voltage the air purifier was running to the motor before I pulled it), and yellow connected to nothing.

I found some PDFs from the manufacturer for similar-looking fans, such as the following:


And they reference the following connections:


But they don't say what those mean or what color they're supposed to be.

I'm at a loss. Any help or direction would be really appreciated.

  • \$\begingroup\$ do you still have the air purifier? maybe you could measure it \$\endgroup\$ Commented May 4, 2023 at 22:22
  • \$\begingroup\$ reference the following connections: PWM TC VC CC CS ... they are functions not connections \$\endgroup\$
    – jsotola
    Commented May 4, 2023 at 23:02
  • \$\begingroup\$ try to find a service manual for the appliance \$\endgroup\$
    – jsotola
    Commented May 5, 2023 at 1:02

1 Answer 1


I've tried to gather the pin assignment / connection references from various sources.

  1. From a similar motor name plate.

enter image description here

  1. From a 310V DC brushless 5-wire DC fan motor drive / control board for inverter air conditioner.

enter image description here

  1. From a Samsung air conditioner service manual.

enter image description here

Based on the above, the motor cable colour code would, most probably, be as follows:

Red - Vm - 310 V DC

Black - Ground

White - Vcc - 15 V DC

Yellow - Vsp - RPM reference (PWM)

Blue - PG - RPM feedback


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