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#192423 02/13/10 01:45 AM
Joined: Feb 2010
Posts: 2
New Member
Motor is for church. Blower on heat exchanger. Fire destroyed leads to motor and need to know which wire goes where to reconnect. Motor is good. Replacement motor runs to fast. I am attaching a file with the motor info that I know.

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Joined: Feb 2008
Posts: 165

Joined: Feb 2010
Posts: 2
New Member
Thanks for the info, but that web site really doesn't help me. This motor only has 4 leads. I am pretty sure this is a PSC type motor, and as you can see from the name plate it can be wired for high and low voltage. It was used with an autotransformer for speed control, but all the wiring was removed before I seen it. I need to know if both windings are connected to the speed control and which ends. I sort of think booth windings would be connected in parallel, since I pretty sure they be in series for hight voltage. It was used on 120 v.
Thanks fixit100

Joined: Dec 2000
Posts: 4,288

Have you been to Scott35's "Technical Reference Area" on this forum?

He's got schematics for all kinds of motors there.

Joined: Jun 2007
Posts: 301
I cannot read the nameplate. Please write out the specs on it.

Joined: Mar 2005
Posts: 1,803
Q1. If it's not wired, how do you know the motor is good?

Assuming this is a [serviceable] fractional [1/6HP] psc. [?] :-

850prm on the plate means it has 8 poles, an expensive to replace item [Baldor $600+]. And explains why the replacement ran too fast.
[Motor rpm = 120 x hz / no of poles.]

Winding A-B is the run winding.

Winding C-D is a start winding, [you can see the capacitor between slots 16 and 34 in your drawing].

The wiring is simple. Take 120v 60hz to a link fitted between C and A.
Fit a link between D and B and connect to the other side of 120V 60hz. Fit a switch connection and try a quick blip to see if it starts. Take care not to prolong the current if all you get is a buzzz!! No start? The capacitor may be duff.
About 5uf would be the approx cap size for this size motor, if the markings on the original are unclear.
Now all you need to see is if it spins CW or CCW for your application. Some pscs can be reversed.

Good luck. Let us know if and when you've let the smoke out!! sick

Wood work but can't!
Joined: Feb 2003
Posts: 939
One thing I can able read the name plate most of it anyway here it is.

1/5 CV { HP }
850 T/ Min { RPM }
60 HZ
110 volts @ 1.8 A
220 volts @ .9 A

so I am pretty sure this is a dual voltage PSC connected motour and I am thinking the 4 leads are for changing voltage on the motour so you have A B C D marking so A et B is one set of coil while C et D is on other set of coil so to order to run this in 120 volt format you need bring L1 with A et C then netural will be B et D that should work only if le capaitor is permament connected inside of the windings.


Pas de problme,il marche n'est-ce pas?"(No problem, it works doesn't it?)

Joined: Nov 2007
Posts: 763
Holy cow, you guys have way better eyes than I do.
I can't even make out that nameplate data or pic when I zoom in on it. frown

Joined: Oct 2000
Posts: 2,722
Broom Pusher and


Let us know if and when you've let the smoke out!! sick



Connect the new Motor for a 120V connection, then run it from the Autotransformer you had mentioned, as described below:

  1. Connect one Motor lead to the Autotransformer's output.
  2. Connect the Ungrounded Conductor of the 120V input Circuit to the desired tap on the Autotransformer.
  3. Connect the Grounded "Neutral" Conductor of the 120V input Circuit to the "Common" connection point of the Motor's Windings.

Refer to this drawing for details:

[Linked Image]


Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!
Joined: Oct 2000
Posts: 2,722
Broom Pusher and

What's the status of this Motor scenario, Fixit?


Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!

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