Hi there.
I am new to this forum and not sure if this is the correct place to post?
I got a 230Vdc treadmill motor with no controller.
I bought a 4000w speed controller from amazon 230Vac to 230Vac with a bridge rectifier.
I connected the speed controller to the mains and the outgoing terminals to the bridge rectifier then through a choke then to the motor.
My problem is when I turn on the power the motor start straight away and the potentiometer is turned completely left.
When I turn the potentiometer clockwise the motor RPM increase.
As far as I know if the potentiometer is turned completely to the left the motor should not start when the power is turned on it should only start when you turn the potentiometer clockwise.
I have a 500K potentiometer.
I also tried 2 speed controllers and both doing the same can someone please help?
Regards
Johannes

 

Do you have a link to the controllers and/or the motor?
I suspect they are simple Triac/rectifier versions, rather the PWM variety.
The controller most likely has enough output to operate the motor, off-load.

 

Do you have a link to the controllers and/or the motor?
I suspect they are simple Triac/rectifier versions, rather the PWM variety.
The controller most likely has enough output to operate the motor, off-load.

Hi
Controller link:

https://www.amazon.co.uk/MagiDeal-Controlled-Rectifier-Controller-Electronic/dp/B07BGW7H3P

Rectifire link:

https://uk.rs-online.com/web/p/bridge-rectifiers/6875803

 

500k is a little high, normally a 5k to 10k is used,
Is this what the unit calls for?
Or I missed it the pot is included?

 

How fast does the motor turn when you switch it on?
If you can live with that speed, a pot with a SW at zero could be used in place of the original in order to stop the motor.

 

500k is a little high, normally a 5k to 10k is used,
Is this what the unit calls for?

It came with a 500k, other people on youtube have the same units and it look like it work for them.

How fast does the motor turn when you switch it on?
If you can live with that speed, a pot with a SW at zero could be used in place of the original in order to stop the motor.

Hi it is about 500rmp, but will be better if it not start when i turn the power on.
I also tried a 5k pot and still the same.

 

And you have the rectifier AC input connected to the controller output, rectifier DC +ve & -ve to the motor?
Try a lamp on the controller output, no bridge rectifier.

 

And you have the rectifier AC input connected to the controller output, rectifier DC +ve & -ve to the motor?
Try a lamp on the controller output, no bridge rectifier.

ac coming from controller to bridge rectifier and + and Minus dc going to motor.

 

ac coming from controller to bridge rectifier and + and Minus dc going to motor.

Hi there
Thank you very much for your advise!!

I got myself a better speed controller and it is working well.

https://uk.rs-online.com/web/p/fan-speed-controllers/3289098/

It just got one issue with it, when I turn the power on the motor start spinning slowly this is with the potentiometer completely to the left. Then when I turn the potentiometer clockwise to increase the rpm's the rpm's increased then when I turn the potentiometer completely anti clockwise the motor slow down and completely stop then all working well.
Is there something I can add the initial start-up when I turn the power on? The pots are set correctly because the motor stop after I increase the rpm's and then turn the potentiometer completely anti clockwise

 

The simple/best way is to use a pot with a ON/OFF SW included on the back of it, this would be wired into the +ve end of the supply to the pot.

 

The simple/best way is to use a pot with a ON/OFF SW included on the back of it, this would be wired into the +ve end of the supply to the pot.

My power supply got a on/off switch, I Just thought I can add a resistor or something to stop the initial spin of the motor.

 

The best way is usually the method I mentioned.

 

The best way is usually the method I mentioned.

Thank you very much, I got another speed controller and it is working well.
One question my Motor is a 230Vdc 4800rpm the question if I turn the potentiometer from zero to quater way it is already at 4800rpm when I turn it further it go up to 12000rpm. Any idea why as the motor is only rated for 4800rpm at 23oVdc?

 

4800RPM is approaching the limit for a DC motor of that size.
Most TM motors are 90VDC, or 160vdc Does the plate actual state 230vdc?
You should not normally exceed the plate rated RPM.

 

4800RPM is approaching the limit for a DC motor of that size.
Most TM motors are 90VDC, or 160vdc Does the plate actual state 230vdc?
You should not normally exceed the plate rated RPM.

Hi yes the motor is rated for 230Vdc, see attached image

 

Chinese Origin!
It could be that the motor is rated this high in voltage, but not continuous, IOW although the supply may be as high as 230vdc, the DC content is made up of a PWM or phase controlled sine wave where the motor current is also at a low mean level.

 

Chinese Origin!
It could be that the motor is rated this high in voltage, but not continuous, IOW although the supply may be as high as 230vdc, the DC content is made up of a PWM or phase controlled sine wave where the motor current is also at a low mean level.

So what will you recommend as I got a AC SCR Speed controller through a Bridge Rectifire. Will a different pot make a difference?

 

What you would need to do is wire in a series resistor from the 'hot' end of the pot to the wire that connected to this point. May take a little experimenting.

 

What you would need to do is wire in a series resistor from the 'hot' end of the pot to the wire that connected to this point. May take a little experimenting.

Hi There
Do you know how to add a smoothing capacitor and resistor to the motor dc feed to smooth the signal?
If yes how to calculate the size of the cap and resistor?
Regards

 

You would just need a Cap. ~200uF 250v if running off of N.A. 120v
Across the output of the bridge.