I hate it when that happens1

The motor and tank on my large compressor are from a Husky that fell over. The pump is Kellogg-American, the pressure switch is from Northern. When I looked at the display units in Home Depot to see how the pump and unloader were set up I noticed several parts missing. The service counter clerk told me they couldn't order replacement parts so frustrated customers just stole them.
jsw

The SA-200 auxiliary power is DC. If your compressor has a piston pump with belt drive, there is a 99.5% chance that you have a cap start AC motor on it. Feeding it DC is a direct short. More than likely you incinerated the compressor switch with some hope you did not take out the motor also.
The circular saw has brushes, is a universal motor, runs just fine on DC. Since it runs, looks like you did not wipe out the aux power windings on the SA-200
The switch is a standard item, come in a couple of pressure ranges. $30 to $40
SteveB wrote:

It's not likely that any replacement parts have to be supplied by the manufacturer, as most equipment makers don't manufacture their own electrical components.
As a blind, wild guess I'd say it's likely that a fatigued wire terminal burned off the end of a wire inside the switch box (or possibly the motor if it's nearby), but it might be a little more complicated than just replacing a wire terminal. The pressure switch may need to be replaced if a terminal on it is damaged. Air compressor pressure switches are available at various hardware and electrical parts stores. You or your electrical-background friend should be able to get enough information from the markings on the old switch, to be able to select a proper replacement.
You may need to adjust the cut-in and cut-out limits for safe and efficient operation of the compressor. If these adjustments are completely unfamiliar to you, be sure to get someone with the proper experience to install and adjust a new pressure switch, instead of just guessing. An improperly adjusted pressure switch can be hazardous. A safety pressure relief valve should protect the tank from excessive pressure, but again, we're all blind to the actual setup you have.
Regardless of the type of failure that's taken place, you'll be wise to make sure the compressor and safety relief valve operate properly after making any repairs.

Yeow, I had no idea what the Lincoln unit was, Roy. If there is space near that receptacle, it would be a good place for a label.

Blink blink..you plugged in an AC machine to a DC welder output?
Go out and check the tank switch...with an OHM meter...you know..the meter with the black and red leads....on the upside down horseshoe shape on the scale
Gunner
"Somewhere a True Believer is training to kill you. He is training with minimum food or water,in austere conditions, day and night. The only thing clean on him is his weapon. He doesn't worry about what workout to do--- his rucksack weighs what it weighs, and he runs until the enemy stops chasing him. The True Believer doesn't care 'how hard it is'; he knows he either wins or he dies. He doesn't go home at 1700; he is home. He knows only the 'Cause.' Now, who wants to quit?"
NCOIC of the Special Forces Assessment and Selection Course in a welcome speech to new SF candidates

I am surprised that smoke came out of a pressure switch. There should not be much that would smoke generating stuff in a pressure switch.
This is a direct drive unit, right?
Pressure switch is no big deal, about $25 or so depending on features. Everything else depends.
Can you trace where exactly the fault occurs. Does it hum when powered on?
i

Well, as RoyJ had said in another reply, the auxiliary output voltage from a Lincoln SA-200 is DC instead of AC, so the regular single phase motor looked like a dead short to the DC voltage. The pressure switch contact was the weakest point of failure under those conditions.

Two questions:-
1) Is the auxiliary output receptacle different from an normal US mains receptacle? If not, why not? If so, didn't that make the OP wonder...
2) Where is the fuse/circuit breaker in the circuit and why didn't it operate?
Mark Rand RTFM

The original outlet is a two prong round part. However they get replaced frequently with a standard outlet so that common tools/lights and the like can be plugged in without changing anything else. They usually also have a tag that says DC output as well those also get painted over or worn off over the years. The SA started in production over 50 years ago!
has a picture of an older one.
Switch contacts handled less current than the fuse.

Not sure which model of the SA200 that you have, but manuals shown on the Lincoln website show that the amperage rating for the auxiliary =93power plug=94 (see page 6) is either rated for 9 or 15 amps @ 115 VDC:

Iggy - Coil - black plastic solenoid expecting AC for reactive impedance but with dc only had copper resistance to limit current.
Martin
Ignoramus4212 wrote:

And that old-style Twistlock NEMA L1-15R receptacle that is hard to get L1-15P plug caps for is easily replaced with a US standard NEMA 5-15R 1.4" round single receptacle.
Or you cut a larger rectangular hole for a standard duplex 5-15R receptacle and a steel cover plate.
Or there isn't one on the welder... Probably would be a good idea to install a breaker or fuse on the welder, especially if you have one of the 9A models.
And put a big tag or sign on the SA200 -
"WARNING! 120V DC Output - Use Incandescent Lights or Universal Motor tools only! If it doesn't have brushes in the motor, Do Not Connect It Here!!"
Most old-style circular saws like the clasic Skil 77, and some single-speed drills and saws are universal motors. If the motor is variable speed or has a capacitor, it probably Will Not run on DC.
Then replace the pressure switch on the air compressor, the contacts probably fried.
Don't bother going to Husky, they just buy from SquareD and mark it up. SquareD makes most of the OEM pressure switches, and if it came from a European source the SquareD Telemechanique division has that market cornered.
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Hey! It's only the second stupid thing I've ever done in my life. I forget what the other was ..........
Steve ;-)