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blowing power supplies ;(

L

ltj

Jan 1, 1970
0
I have two Phihong 9V 1.67A open frame supplies that I've managed to blow...
they now have no output except some mVs pulsing every few seconds.
(Mouser# 552-PSA-15LN3-090).

I tested them on the bench and they were initially fine. They seemed to die
when I was attaching AC to them. I say this because it was all working
fine, I unplugged it to work on other things then plugged it back in and got
nothing at that point. There was no load attached at the time. The other
one I never got to work (except on the bench).

The factory power was running 127VAC and is probably noisy but everying else
we hooked up runs fine including a similar 5V Mean Well open frame supply.

Any thoughts or suggestions on what could have caused this and how to avoid
it in the future?
newbie,
ltj
 
W

William P.N. Smith

Jan 1, 1970
0
ltj said:
There was no load attached at the time.

Many switchers will fail to run (or trip a crowbar or other shutdown
circuit) with no load...
 
L

ltj

Jan 1, 1970
0
Would what you described cause permanent damage?

It is rated at 0-1.67A. Does this means it is "ok" with no load?

I just realized that the enclosure might not have been grounded properly. I
had no ground when bench testing and it ran fine. Perhaps it matters out on
the floor?

thx
 
W

William P.N. Smith

Jan 1, 1970
0
ltj said:
Would what you described cause permanent damage?

It is rated at 0-1.67A. Does this means it is "ok" with no load?

I just realized that the enclosure might not have been grounded properly. I
had no ground when bench testing and it ran fine. Perhaps it matters out on
the floor?

thx


Many switchers will fail to run (or trip a crowbar or other shutdown
circuit) with no load...

No, and it should mean that, and grounding shouldn't make much
difference. I'd try it with a 10-ohm resistor and see if it makes any
difference...
 
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