I acquired a blower assembly from an old air handling system, with the intention of using it as an exhaust fan in my workshop.

It came as an assembled unit of blower and motor on a subframe. The wires had been cut prior to my arrival.

I have Googled "7-wire motor," "AC motor wiring," "brushless AC motor wiring," and many more ways of trying to describe what I have in-hand. I have been unsuccessful in finding useful information about how to wire this up.

I have found a couple of things that appeared to describe how to figure out what wires do what - one of which takes me through testing for continuity and says I should find two separate groups. I don't.

ALL wires have continuity to each other. Verified by using a 12v battery and a light bulb, + to each wire and - to others for each of the colors. Bulb lights up every which way.

Motor label info: 493 (probably a part number i guess) 1PHASE TYPE CA0514D-R SANSO POLES 4 OUTPUT 85 W VOLT 220-240 V HZ 50 07.08.28 KC

Wires: Black, Red, Yellow, Blue, Orange, Grey, White

What I want to do:

1) Make it run, using any built-in speed differences that may be a part of the existing setup.

2) Alternately, just make it run, full on.

I sorta thought this would just be simple, but I guess not. Don't want to feed power to any wires until I can tell what is what. Need help. Below are pics of the lot.

Motor Housing


  • \$\begingroup\$ "ALL wires have continuity to each other, if you rotate the fan drum. Meaning the continuity is dependent on the degree location of the drum" sounds like there is a problem inside the motor. Did you check continuity with the housing? \$\endgroup\$
    – user80875
    Commented Aug 9, 2016 at 23:44
  • \$\begingroup\$ Just checked continuity from wires to housing - none . \$\endgroup\$
    – 111936
    Commented Aug 9, 2016 at 23:49
  • \$\begingroup\$ When I wrote that continuity depends on drum degree of rotation I meant that if you test for Black to Yellow, it will not have continuity until you begin to rotate the drum, and continuity will come on and off as the drum rotates. \$\endgroup\$
    – 111936
    Commented Aug 9, 2016 at 23:51
  • 1
    \$\begingroup\$ @DwayneReid - I already did. No response. \$\endgroup\$
    – 111936
    Commented Aug 10, 2016 at 2:34
  • 3
    \$\begingroup\$ Forget beeps - you need actual resistance measurements to have any hope at all. \$\endgroup\$
    – user16324
    Commented Aug 10, 2016 at 8:42

2 Answers 2


Here is a guess as to what the diagram might be. It might be possible to figure out which wire is which and whether or not this diagram makes sense by careful measurement of resistance. I think I have the L-M-H sequence backwards.

enter image description here

More re resistance measurements etc.

To figure out which winding is which and which speed and voltage taps are connected to each winding, you need resistance measurements that distinguish very small resistance differences, perhaps 0.1 or even 0.01 ohms. If you can verify which wire is neutral and which winding is which, you may be able to run the motor, measure current and estimate speed to help determine the rest. Accurately (and inexpensively) measuring low ohms is a good subject to research.

If you can't find detailed information on the motor, you will also need to guess at the capacitor value. You will be able to find tables that give ranges based on motor power and voltage.

You might consider taking the motor housing off and carefully examining the lead wire routing, the connections to the windings and the winding wire size. Be careful doing that. The windings are somewhat fragile and there may be several washers on each end of the shaft that need to be in the right order. Those tend to stick either on the shaft (good) or on the bearing in the housing where they might drop off when you are not looking (bad). The bearings themselves may stay on the shaft or in the housing.

Without knowing the motor current rating, it may be difficult to know if you have everything right if you get the motor running. If you don't know why this motor was taken out or why the air handling system was scrapped, you don't have any reason to assume this is a good motor.

  • \$\begingroup\$ One Google result I found had step one as isolating a 'starting circuit' by measuring continuity, and then as step two measuring resistance to establish H/M/L wires. Regretfully with continuity on all wires I cannot tell where to start the identification. Any tips on how I can find out? Would it be multiple wires with same resistance as the 'starting circuit'? I'm really baffled here... \$\endgroup\$
    – 111936
    Commented Aug 10, 2016 at 6:00
  • \$\begingroup\$ The "starting circuit" would be a centrifugal switch or some current sensing device that opens after the motor is up to speed. Since you couldn't see anything inside the motor and since the motor is only rated 85 watts output, I think that is unlikely. My guess is based on more than three speeds being unlikely and speed being quite sensitive to voltage being likely. \$\endgroup\$
    – user80875
    Commented Aug 10, 2016 at 12:26

Being persistent with the company that sells the units that this blower was removed from yielded this drawing. The wiring is detailed in it.

Hope if anyone else ever Googles the problem they take my advice to chase answers with people that use the part/motor/etc and not just the manufacturer (the manufacturer never replied to my multiple emails).

And just an FYI - It is now housed in an MDF box and in use. Added a 4-way 240v switch from the local electrics supply and an old extension cord to feed it.

Schematic from Blower Motor


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