need help with smps for a welding machine w/ universal voltage input.....

Thread Starter

knonuthin

Joined Apr 28, 2016
4
ok i have an issue with my welder. It can run on 110 or 220. I almost always have it hooked to 220. Now whenever i turn it on when plugged into 220 it throws the breaker as if it were a dead short. If i plug it in to 110 there is a bank of relays i can hear them switching the lights come on but nothing else....? I'm guessing it is something with the power supply i should mention this is an inverter welding machine basically a big high current chopper...
 

ian field

Joined Oct 27, 2012
6,539
ok i have an issue with my welder. It can run on 110 or 220. I almost always have it hooked to 220. Now whenever i turn it on when plugged into 220 it throws the breaker as if it were a dead short. If i plug it in to 110 there is a bank of relays i can hear them switching the lights come on but nothing else....? I'm guessing it is something with the power supply i should mention this is an inverter welding machine basically a big high current chopper...
How are you getting 110V? - the SMPSU will probably throw a wobbler if fed from an excessive impedance supply.

You're probably lucky it didn't go bang on 220V. Early universal voltage units created a voltage doubling rectifier by using 2 reservoir caps in series and shorting the tap to one of the AC arms of the bridge rectifier. Early on it was a user set jumper link, this was superseded by a triac to make the connection. It started with a discrete component voltage detector, but fully integrated units arrived eventually.

A fully integrated type might be available as an off the shelf part. I'd have to see the discrete component type and make a decision, repair it or decide what voltage to use and hard wire it or not hard wire it.
 

Thread Starter

knonuthin

Joined Apr 28, 2016
4
from what i can tell and bear in mind this is just based on looking at the traces on the board (not to mention im a metal worker not a technician) there are 2 or 4 sets of optocouplers and two m osfets. there is also an 8 pin smd ic on the back which i was thinking may be an op amp but i cannot read what was written on it. as for the discrete componants there is a bank of ...resistors..????... marked ntc 470.... i dont know if any of that helps but either way i appreciate your attention and input...
 

Thread Starter

knonuthin

Joined Apr 28, 2016
4
its a simadre 5200 3-in -1 welder and plasma cutter. i tried to find a schematic and tried emailing the company with no luck.
 

ian field

Joined Oct 27, 2012
6,539
from what i can tell and bear in mind this is just based on looking at the traces on the board (not to mention im a metal worker not a technician) there are 2 or 4 sets of optocouplers and two m osfets. there is also an 8 pin smd ic on the back which i was thinking may be an op amp but i cannot read what was written on it. as for the discrete componants there is a bank of ...resistors..????... marked ntc 470.... i dont know if any of that helps but either way i appreciate your attention and input...
There was a DIL-8 voltage sensor that directly drives the triac - I have no idea whether it was produced in SOIC-8 footprint.

Could be anything - a lot of switcher control chips are 8 pin.

The number off it might help.
 

Thread Starter

knonuthin

Joined Apr 28, 2016
4
i am having a hell of a time trying to make out what was written on that surface mount ic, i was however able to read the writing on a 3 pin to-220 component ....FQP 5N50C .... Is it possible this is my problem...?
 

ian field

Joined Oct 27, 2012
6,539
i am having a hell of a time trying to make out what was written on that surface mount ic, i was however able to read the writing on a 3 pin to-220 component ....FQP 5N50C .... Is it possible this is my problem...?
Not possible to tell till you pick up the DMM and start checking stuff.
 
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