Electronic project That stopped Working

Thread Starter

Drew . G. H. 1066

Joined Feb 14, 2023
27
Hi,
I need some advice with a problem I experiencing on a project I am working on.

The project consists of a 600W AC to DC converter 230V TO 24V 25-30A power switch transformer, a 10-50V 40A DC Motor Speed control PWM HHO RC controller 12V 24V, and a 350W 24 volt D.C motor, rated current 18.7A.

There is a pulley on the shaft of the motor that can be connected to another pulley situated on a drive shaft, with a drive belt, on this shaft is also a fly wheel, and a large pulley, which is not attached to anything at the moment.

The speed controller has developed a fault where the current flows through the circuitry by passing the on and off speed control switch, so that when you turn the power on, the motor starts spinning

Before the problem had accrued I had done tests runs with out a drive belt being attached between the two pulleys. Varying the speed over a five minute test run, and there were know problem.

Next I connected the drive belt between the two pulleys, started spinning the flywheel by hand, (so that the motor did not have its dead weight to contend with when it started spinning) then turned the speed controller on, and set it at a quarter of a turn. Ran it for five minutes, know problems.

Did exactly the same again, but this time I set the speed controller to half a turn, it ran for 4 minutes before the motor lost power, and everything started slowing down, then stopped.

I tested the AC-DC converter that works O.K, I tested the motor, and that works O.K

I did wonder whether the flywheel momentum could have build up, so that it ended up spinning faster, than the speed the controller was set at. So that the electric motor was forced to spin faster, with out the increase of power to do this. But I am just guessing.

Any suggestion on what might have caused the damaging to the speed controller, would be greatly appreciated.
 

Irving

Joined Jan 30, 2016
4,001
I doubt anyone can give you a definitive answer on this. Sounds like the controller just wasn't able to cope with reverse EMF from the motor when not powered, but that might just be clutching at straws!

Can you provide links to the individual parts mentioned.
 

Thread Starter

Drew . G. H. 1066

Joined Feb 14, 2023
27
Thanks for your thoughts on what the problem might be.

When you say, can I provide links to the individual parts, what type of information do you require ?

You mention the controller might not be able to cope with this reverse EMF from the motor, is there any way of protecting the controller from this, when it happens?
 

Thread Starter

Drew . G. H. 1066

Joined Feb 14, 2023
27
I have a problem with a speed controller on a project that I built.

A brief description of the component involved. There is a 230 volt AC to 24 volt DC converter, which connects to the 24 volt speed controller, which is connects to a 24 volt D.C Motor. I Did a test run for five minutes, to check that everything working O.K, which it did.

Then attached a belt to a pulley on the motor, to a pulley on a drive shaft, on this shaft is a flywheel.
I spun the flywheel (so that the motor did not have its dead weight to contend with when it started spinning) turned the speed controller on a quarter turn, and the motor started spinning, ran the test for five minutes, everything worked O.K
But when I did the next test run, at a half speed, (spinning the flywheel as I did before), everything worked O.K for four minutes. Then everything started to slow down and stopped, (the flywheel on this test was really moving quite fast). The reason why I mention this, is because, I tested the motor, and the converter, and they working O.K
The on and off speed control switch has developed a fault. it seem, I did a separate test of the speed controller, and the motor using a 24volt battery set up. When I turned the power on, with the speed controller switch in the off position, the power bye passes the switch, because the motor started spinning.
I was wonder whether the flywheel momentum could have build up, so that it ended up spinning faster than the speed controller, was set at, for the electric motor to rotate at, and so that the electric motor was forced to spin faster, than it should relating to the setting on the speed controller, and this is what caused the problem, but this is hypothesising on my part.

Any suggestion on what might have caused the damaging to the speed controller, and how to go about repairing the circuit board, would be greatly appreciated, and also how to stop this happening again.
 

Alec_t

Joined Sep 17, 2013
14,382
As Irving said, a possible cause is the back-emf generated by the motor when the supply is switched off. The links he requested are links to web-sites or datasheets where technical information (e.g. current/voltage/wattage ratings) of the components of your system are described.
It sounds as though the power semiconductors in the speed controller are shorted.
Btw, there is no need to repeat most/all of your original text.
 

bidrohini

Joined Jul 29, 2022
190
It's possible that the fault with the speed controller was caused by overloading. The motor is rated for a maximum current of 18.7A, and the speed controller is rated for a maximum current of 40A, so it's possible that the increased load from the flywheel and pulley system caused the current to exceed the controller's rated capacity, leading to the fault.

It's also possible that there was a short circuit or other electrical issue that caused the fault.
 

Thread Starter

Drew . G. H. 1066

Joined Feb 14, 2023
27
As Irving said, a possible cause is the back-emf generated by the motor when the supply is switched off. The links he requested are links to web-sites or datasheets where technical information (e.g. current/voltage/wattage ratings) of the components of your system are described.
It sounds as though the power semiconductors in the speed controller are shorted.
Btw, there is no need to repeat most/all of your original text.
Thank you for reply to my thread, and sorry for the late reply. Just to clarify one thing you mention in your thread, about the supply being switched off. The power was not switched off when I carried out the last test at half speed, the motor just stopped spinning.
 

Thread Starter

Drew . G. H. 1066

Joined Feb 14, 2023
27
As Irving said, a possible cause is the back-emf generated by the motor when the supply is switched off. The links he requested are links to web-sites or datasheets where technical information (e.g. current/voltage/wattage ratings) of the components of your system are described.
It sounds as though the power semiconductors in the speed controller are shorted.
Btw, there is no need to repeat most/all of your original text.
Thank you for your reply to my thread, and sorry for the delay in replying. Just to clarify one thing, on the last test run at half speed, the power was not switch off. Four minutes into the test, the motor just stopped spinning.
 
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