Hi all,

Attached is a picture of a circuit I am attempting to troubleshoot. This is part of a larger design which will ultimately create a battery-powered yard wagon as a hobby project.

I am using an RC remote to control it, hence the "Receiver" in the diagram. I am programming one of the switches on the RC controller to act as an Emergency Stop in case things go sideways. This particular circuit is intended to control a 36V solenoid, which can open the battery bank and remove all power from the cart electronics.

Starting out, I had just the "Receiver" and the "PWM Switch". However, the PWM Switch is only rated for 30V. The higher volage from the 36V solenoid eventually killed it (I assume) after ~50 or so actuations.

Consequently, I used 12VDC from elsewhere in the wagon to the "PWM Switch" and added the "DC Switch" which is rated for 36VDC.

However, the problem I am seeing is that whenever the "PWM Switch" is actuated, it immediately turns back off. (I don't think it ever completely actuates.) I tried a couple of test cases: 1) When I disconnect the "PWM Switch" from the "DC Switch", the PWM Switch can actuate just fine as expected and 2) When I apply 12VDC from supply to the "DC Switch", the "DC Switch" actuates correctly as well. So both parts seems to be operating correctly in isolation.

It therefore seems the "PWM Switch" does not like something about being connected to the "DC Switch" and the "PWM Switch" simply does not actuate in this case.

Any ideas what may be causing this behavior and how to correct it? Thanks!

 

Post links to that "PWM" switch and the DC switch please.
I'm skeptical about that module you call "PWM switch".

 

Here is a link to the PWM switch: https://a.aliexpress.com/_mrbGH1t

Here is a link to the DC Switch: https://protosupplies.com/product/d4184-mosfet-control-module/

Another data point. I swapped the DC Switch with the part here and it works just fine:
https://a.aliexpress.com/_mtutxWT

I can accept this outcome, but I would prefer to use the one in my original post because it is simpler and cheaper.

 

I would prefer to use the one in my original post because it is simpler and cheaper.

Can you show exactly how you have the modules wired?

 

Argh! I swapped back in the original DC switch to take this picture and it is now working as expected. Not sure what's different this time... I'd been messing with it on and off the past couple of days and no luck until now.

I'll post back if something reappears. Thanks all!

 

What is not clear to me is what the PWM device is supposed to do for you. I am guessing that the control is to be simply on/off (START/STOP) , and not variable speed. I do not follow wiring photos.

 

Your guess is correct.

 

Since we have no information as to any current being controlled in any segment of the assembly it is not likely that any useful suggestions are possible.
UNLESS some participant has remote mind reading abilities.

 

The wiring between the modules is fairly simple.
Apparently the TS figured it out as it's working now.
Probably just a loose connection.