Guest
Greetings All,
I have a small Lincoln wirefeed welder. Depending on the wire and the
process the welding wire will be either + or - polarity. To switch
polarity two thumb nuts must be removed and swapped. This sounds
easier than it is. Partly because of the way the welder is made. I
swap polarity on a pretty regular basis so I would like to do this
with just a switch. The max voltage is 30 volts and the max amperage
is 140 amps. That 140 amps is very brief, maybe just a few seconds.
Continuous current is 100 amps and 30 volts. I thought an H bridge
would work but I can't find and MOSFETS that are rated this high for
positive current. Can the MOSFETS be paralleled easily? Is there a
better choice? The polarity would never be changed with power applied.
I thought about using a relay with contacts rated at 150 amps or a
double pole contactor or even a big toggle switch. All these options
are too expensive. I'm cheap. I don't wanna spend more than $75 US on
this project. Anybody here have some guidance?
Thanks,
Eric
I have a small Lincoln wirefeed welder. Depending on the wire and the
process the welding wire will be either + or - polarity. To switch
polarity two thumb nuts must be removed and swapped. This sounds
easier than it is. Partly because of the way the welder is made. I
swap polarity on a pretty regular basis so I would like to do this
with just a switch. The max voltage is 30 volts and the max amperage
is 140 amps. That 140 amps is very brief, maybe just a few seconds.
Continuous current is 100 amps and 30 volts. I thought an H bridge
would work but I can't find and MOSFETS that are rated this high for
positive current. Can the MOSFETS be paralleled easily? Is there a
better choice? The polarity would never be changed with power applied.
I thought about using a relay with contacts rated at 150 amps or a
double pole contactor or even a big toggle switch. All these options
are too expensive. I'm cheap. I don't wanna spend more than $75 US on
this project. Anybody here have some guidance?
Thanks,
Eric