HELP!!! Power Supply Troubles!!!

I still say there is a short somewhere. How about your mounting screws? The spec lists specific lengths for the screw depth. If too long a screw is used, there is a possibility of an internal short.
 
Boswell said:
If they work Out-of-Circuit and fail In-Circuit. then I would suspect that you have a short and the pwr supply protection circuit is kicking in.
Click to expand...

I've had them not turn on with and without a load. It didn't seem to matter.
 
RJSakowski said:
I still say there is a short somewhere. How about your mounting screws? The spec lists specific lengths for the screw depth. If too long a screw is used, there is a possibility of an internal short.
Click to expand...

Yeah, I thought about that. My mounting screws are 3/8" long and go through a 1/4" Plexiglas mounting plate. So, only 1/8" is going into the PS.

I remounted them last night and I can't get them to fail now.

I rewired them (mounted to Plexiglas) this morning to my motor controllers and they've been consistently working!

I'm at a loss to explain this.

They seem to work when they want to and not work when they want to.

I don't think Automation Technologies is letting me return them and exchange them for the unregulated power supply. They just want me to send them back for a replacement.
 
Another thought is a wire whisker from one of your wires shorting out. Easy enough to do that. If the problem reoccurs, check resistance with the power off. In fact I would do that now while everything is working to have a baseline for comparison if when things go south again.
 
It could be that the overvoltage protection is kicking in and shutting down the supply
years ago I had some 15v power supplies do that
Do you have an adjustment sheet for the supply
I used to turn the adjustment pot to zero then slowly increase it desired voltage
If I went too far the power supply would trip and would only power up when the
voltage was lowered and powered down and back up
Not sure if this if the problem but worth checking out
 
Yes, there is a pot to control the output voltage. There is an over voltage circuit.

It's possible the over voltage circuit is getting triggered. I'll measure the output voltage tonight.
 
If you can find an adjustment sheet on the supply it should show how to properly adjust the supply
The supplies I worked with you set your max voltage with one pot then set the over voltage pot to trip
if it went higher
These were older power supplies your power supplies might have a different procedure
Hope it helps
 
I misspoke. The mounting screws were M4 x 6mm going through a 1/8" aluminum plate.

There are no whiskers that I could see on either unit.

The pot control was able to get the output voltage to about 53V. But, I couldn't get it to fail after numerous tries and various settings.
 
Sounds like its working intermittent problems are hard to trouble shoot
I would not trust them unless I knew why they are working now
My thing would be exchange them for ones that work off the bat if covered under warranty
If you take a chance you are only out 28 dollars each
I think I read they would exchange them
 
I ordered the unregulated power supply from Automation Tech. I'm done with the switching power supplies.

They seem to be offering me a refund on the switching power supplies, but we'll see. It was a little convoluted transaction.

Gory details (to those who are interested):
I ordered the switching PS via eBay. I initially had trouble with one PS. I send them a message and they told me to return it for an exchange. Then, the other PS starting acting up. I sent them two more message: one saying the second one was intermittent and the other asking for an swap with the unregulated PS (and additional $$$). These two email were ignored. Time passes. eBay sends me a message saying they agreed to a refund. It was unclear if this was for one or both PS. So, I sent back both today. We'll see if I get a refund for one or both or an exchange for the same ones. Over the weekend, I order the unregulated PS from their website. Hopefully, everything will work out!
 
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