The driving part is not the problem. The problem starts when you turn off the the motor and the electromagnet field collapses. It sends a voltage spike back thru the SSR and slowly eats away at the electronics. At my work place we went through a learning curve on this when we used SSR's to control several large contactors for 3 phase power.
Your particular application maybe so over engineered that you may not see problems. But if things get out of control that would be the first place I would look.
A SSR should have a series R-C snubber across it to reduce the voltage spikes. Some of the SSRs have this built into them I believe. The application note for the device will probably have recommended values. Usually they are in the region of roughly 50-100ohms and a 0.1uf capacitor. Snubbers across mechanical relay contacts aren't a bad idea either if they are switching significant current. Zero-crossing SSRs are best suited to resistive loads. IIRC, if the voltage and current are out of phase such that enough current is flowing when the voltage across the triac is zero they won't turn off.
I spent about 40 minutes welding scrap last night. 130 A or so. About as much welding minutes per hour as I could expect. Maybe 25% of time was actually spent welding. The water in the cooler got barely warmer (maybe by 5 degrees C or so).
On a related note, I replaced water with pink (purple?) RV antifreeze last night. That way, the coolant will not freeze in my garage in winter.
My Miller cooler holds just short of a full gallon, including what is in the torch hoses. I'm using Miller coolant straight, it is supposed to help the pump and prevent corrosion in the torch, etc.
On mine, the fan is mounted on the pump motor's shaft, so it runs all the time, too.
These snubbers will prevent the high voltage spikes of the RF edge ability that punches through the semiconductor.
Many years ago I fixed a base ball thrower that used two powerful DC motors.
Once I installed the snubbers - don't forget some wattage values - the 'JUGS' (Trademark) (it was in those days of anything goes) - never blew up.
The High School coach pleaded with me - expensive to ship to Washington state - and then pay bill - ugh - fixed it once without thinking - then I fixed it forever.
The students used to freeze stop the wheels (instant HV) so they could haul it in. I used 25 Watt resistors IIRC partly over kill - and who knows the duty cycle hit!
Martin Martin Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net NRA LOH, NRA Life NRA Second Amendment Task Force Charter Founder
I think that the question "Why don't you show us some pictures of your work?" was addressed to someone else and not me. Attributions became a little bit messed up.
Win Hill is obviously not going to say it himself - he is very modest, but he IS one of the world's greatest electronic design engineers, and the co-writer of one of the finest electronic text books "The Art of Electronics"- it certainly helped my degree, and its one of the first books I ever point a raw graduate at.
I have seen pictures of some of the stuff he has built - I suspect a lot of it has been orbited over the years as well.
Sounds like a heat exchanger is needed - as one loop from the stinger brings in hot water and pumps back warm water - another loop is placed to chill the warming water (water to say a term only) and dump the heat elsewhere. A nice portable air conditioner that is a heat pump or not - could be implemented when local power was available. When in the field, a Icebox from a camper that runs on 12 v or propane might be a nice chiller.
Naturally some kit bashing and creative mind work would have to take place.
Solar cells dumping high current into a pair of wires that in turn run through a solid state heat sink (ever see the 12 volt camping ice/beer chests ?) easy to bash. Almost done for you - cooling tank and drain and 12volt plug.
Plug it in and pump 'water' through 3/8" copper tubing - (or other) to a small radiator that might have been a motorcycle add on kit - back to the 12 volt chiller. The box always closed and in the shade - and the bottom (where the heat is - on a larger sheet of metal to conduct ? - truck bed ?
Martin - just had dinner and under boosted blood stream!
Martin Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net NRA LOH, NRA Life NRA Second Amendment Task Force Charter Founder
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