Pacific Scientific treadmill motor. Diagnose/Rebuild/Replace

[rjp]

I have a treadmill (bodyguard Magellein) with a Pacific Scientific 2.3 hp motor that recently started making a fairly loud clicking sound. I took the cover off and I can see an LED indicating current limit flashing or solid red as speed increases, and I smell a burning smell from the motor. I took the motor apart and the brushes looked fine, but I saw a broken wire at one of the communicator contacts. I soldered it back on but this made no difference. The communicator surfaces on the armature near this wire were slightly carboned which I cleaned.

I am wondering if the motor is bad or if this clicking is from a defect in the controller board (some sort of electrical pulsing). Can you guys give me any advice as to how to proceed? Is there a way to test the motor without the controller card such as using a straight DC power supply? Nameplate says 124 vdc 16.8 amps.

Since the motor smells like it is overheating, I'm guessing something is wrong with it though. What are my options? I assume these are pretty darn expensive. Where can I buy a replacement? Can it be rebuilt? where? Is there a way to test the armature windings myself? I'd like to learn about this.

Please tell me about any links for parts, rebuilding info, etc. Also, where can these be purchased new/rebuilt?

Motor Info from nameplate.
Pacific Scientific
Model: PWM 3636-5415-7
Prod Code: FGP1270
16.8A, 124 VDC
2.3 hp, 3590 RPM


Thanks for any help.

Rich

[barts]

Prob. not exactly what you need but the price is right:

http://surpluscenter.com/item.asp?UI...tname=electric

[rjp]

Prob. not exactly what you need but the price is right:

http://surpluscenter.com/item.asp?UI...tname=electric

Thanks, but the motor I have has a shaft on both ends. Flywheel is mounted on rear. Also, it is 2.3 hp continuous duty I believe.

I can not find any info on rebuilding these things other than replacing brushes.

Do you know how to test a motor like this? What should the resistance readings be between various commutator terminals? They all seem to be about the same 0.5 ohms or so. How are the armatures of these PM DC motors wired anyway?

[paulx]

There is a business in Denmark,Maine called The Moir Co. that rewinds small armatures but expect to pay a couple hundred and freight.

[rjp]

I just got off the phone with a very helpful tech guy at Bodyguard Fitness (the treadmill manufacturer) and he explained that the board might just need to be adjusted due to current limit kicking in too soon. He told me the procedure to turn the potentiometer. He was not sure if this could cause the motor to "click" as I mentioned, but said it might due to pulsing the relay at over current.

He explained that I could just put the motor on a 6v battery and see if it then runs silently at low speed. This would separate the problem into either motor or controller board. I will also put a scope on the board output terminals and see if there is any funny stuff in the voltage waveform (pulses?). I though the since the motor is PWM (pulse width modulated) according to the Pacific Scientific site that the controller might be feeding it some fancy pulsed waveform to control speed and touque, but this guy says no. He says it is straight DC simply varying voltage for speed and current as needed for load.

It is so nice to find a tech guy willing to help rather than charge 700 bucks for a new motor.

Does this advice sound right to you more experienced motor guys?

[macona]

No, its not the board. The motor is toast.

[rjp]

No, its not the board. The motor is toast.

OK. Can you tell me why you believe the motor is toast?

[macona]

That wire had to come off for a reason. Best bet is the armature is shorted. This would cause the odor you smelled, over current light and enough heat to unsolder the wire.

The way to test an armature is with a growler. Also check from the commutator segments to ground. You can take to motor to a motor shop and they ought to be able to test it. Also some auto repair shops will have a growler for testing starters.

[J. R. Williams]

Pull the armature from the motor and use a "Growler" to check for internal shorts and a good ohm-meter to check for grounds. Re-winding small DC motor armatures is a costly item.

JRW

[rjp]

That wire had to come off for a reason. Best bet is the armature is shorted. This would cause the odor you smelled, over current light and enough heat to unsolder the wire.

The way to test an armature is with a growler. Also check from the commutator segments to ground. You can take to motor to a motor shop and they ought to be able to test it. Also some auto repair shops will have a growler for testing starters.

Yes. I agree completely about the wire. It probably broke for a reason of overcurrent rather than mechanical strain (it was not soldered originally btw. It was a mechanical crimp connection to the commutator pad.)

I want to take this apart again and measure the armature myself but I need some background first on how it is wired up. Simply measuring the resistance between arbitrary commutator pads appears to tell met nothing since they are all pretty much the same (about 1 ohm). Is this armature just one big coil with taps all throughout its length?