Treadmill motor speed control

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Thread Starter

Blobbybob

Joined Feb 4, 2018
5
Hi all,
I appreciate this has been asked a few times but I can't seem to find a solution using the search function.

I have this motor2018-02-04 16.31.12.jpgand after watching this you tube video

I thought I knew what I was doing whenl bought the same rectifier and controller

The standard potentiometer was 500k and worked, but at 50% the motor was tearing a hole in space and time and more would trip the breaker, not really thinking I bought a cheap 200k pot like the guy in the vid, this popped the breaker as soon as power was supplied even at 0% so then tried a 1m potentiometer with the same spec as the original but that just trips the breaker as soon as power is supplied as well.

Can anyone tell me what I'm doing wrong.

Ps. I'm no electronics expert, so think layman and them dumb it down a bit.
 

MaxHeadRoom

Joined Jul 18, 2013
28,619
If you intend running a T.M. motor with one of those cheapo controllers I would suggest you get rid of the flywheel.
Controllers like the KB series or a low end T.M. board have acceleration pots etc, that make it far easier to run one of these motors.
Max.
 

Thread Starter

Blobbybob

Joined Feb 4, 2018
5
Hi thanks for the reply, I have already removed the flywheel as I need to fit a v pulley to the shaft.

I just can't work out why every value of pot I try except the original blows a fuse, higher or lower?

The 1m potentiometer is 1a 2w I thought that would make the motor run in a lower range of speeds.
 

MaxHeadRoom

Joined Jul 18, 2013
28,619
Sounds like you have something mis-wired.
The problem is the guy in the video is running a Triac controller with a bridge, you need a PWM controller to run this motor effectively and with smooth control.
You can hear how the motor growls at low RPM!.
You can either look for a PWM one on ebay or they are fairly simple to build.
Max.
 

Thread Starter

Blobbybob

Joined Feb 4, 2018
5
Thanks again for taking the time to reply.

Sorry about the you tube links but would you agree that this guys method is more suitable?

 

MaxHeadRoom

Joined Jul 18, 2013
28,619
There is no way that set up runs his 3.0hp 90vdc motor with any efficiency.
Personally I would not even entertain it.
If you keep an eye on ebay you can get a KB drive or a T.M. board for around the price he paid and have a decent controller.
Max.
 

Waynos

Joined Sep 18, 2022
1
Hey friends, for future friends trying to find solutions to problems of this nature, something to consider. In my limited experience with treadmill motors, they are 180 volt DC motors. Peak volts of 110 volts is 180 volts. So if you take your 110VAC and put it through a bridge rectifier you will get 180VDC on your voltmeter. If you live in a 220VAC, 230VAC or 240 VAC country such as New Zealand or Australia, that 220-240 VAV rectified to DC, peak volts is 390-400 V. So that 180V motor will pop the breaker at 50%, which is what friend here said happened. He never mentioned his location and no one asked. So the 110V country experts assume another issue. So, this is possible.

If you have 240VAC at the wall and using a SCR voltage regulator, you always need to stay below 50% speed unless you have a 220/110VAC transformer to step your voltage down. Better to try to make use of the speed control board that comes with the treadmill I reckon. They are designed for the native voltage of whatever country you are in to drive a 180V motor.

Or the gold standard in my opinion, is to find a small 3 phase induction motor and an ebay/aliexpress Variable Frequency Drive (VFD) for maybe $60USD. Way stronger and don't slow down as much as DC motors when you load them up.

Cheers, Waynos
 

MaxHeadRoom

Joined Jul 18, 2013
28,619
Or the gold standard in my opinion, is to find a small 3 phase induction motor and an ebay/aliexpress Variable Frequency Drive (VFD) for maybe $60USD. Way stronger and don't slow down as much as DC motors when you load them up.

Cheers, Waynos
You are probably using the wrong DC motor controller.
DC motors have maximum torque at zero RPM, the torque curve stays fairly flat from 0v to close to max..
They make excellent spindle motors with the right controller, far better than Induction motor.
Typically N.A. T.M.'s have a 90vdc motor, with a rectified 120vac mains they can be taken up to their maximum rpm and then limited.
In a TM application, it is important to control the RPM fairly precisely with a heavy varying load.
 
Last edited:

Pmanhart

Joined Aug 4, 2023
3
Hi all,
I appreciate this has been asked a few times but I can't seem to find a solution using the search function.

I have this motorView attachment 145151and after watching this you tube video

I thought I knew what I was doing whenl bought the same rectifier and controller

The standard potentiometer was 500k and worked, but at 50% the motor was tearing a hole in space and time and more would trip the breaker, not really thinking I bought a cheap 200k pot like the guy in the vid, this popped the breaker as soon as power was supplied even at 0% so then tried a 1m potentiometer with the same spec as the original but that just trips the breaker as soon as power is supplied as well.

Can anyone tell me what I'm doing wrong.

Ps. I'm no electronics expert, so think layman and them dumb it down a bit.
Check out Dazecars on YouTube. He walks you through a very nice variable speed drive for treadmill motors.
 

Alec_t

Joined Sep 17, 2013
14,280
@Pmanhart
Welcome to AAC!
Please check the dates of threads before posting. Resurrecting long-dead threads is not recommended. It's better to start a new thread and provide a link to a much earlier one.
 
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