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Miller S32s contactor install

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  • Miller S32s contactor install

    Hi all, theres alot of hoopla centered around contactors and why they're needed in a roll feed system. I for the life of me don't understand why Miller doesn't just add a contactor in a unit that is rated for so many amps. Well I know why now..Money! Called my local Miller dealer to purchase a contactor for the unit and he tells me he can order one for around $400. O.k. I understand that some people have rent to pay but that kind of money seems more like a mortgage payment! Larry at Weldmart sells aftermarket 250 amp contactors that are made to fit miller for around $275 after shipping...Better! but still too much for my uses. So I had an idea being an owner of a few older diesel trucks and looked into the glow plug contactors that these trucks use which are heavy duty starter selenoids rated at around 150 amps continuous cranking or 250 amps intermittent. These can be purchased at any automotive parts store for around $35 a piece..Best! Gathered the required lead wires and the contactors and some surplus 12v dc power supplies that I obtained from trashed Clear One Conferencing Phone systems at a Job. I managed to fit the Starter Relays Back to back using the same bolts through the rear of the unit. Notice how I managed to feed the external output contactor 2/0 wire across the fronside of the Circuit board and through the motor feeder side to the roller lug. I borrowed 12v from the gas contactor leads to shunt the smaller contactor that sends the voltage to the Starter Relays. The Two 12v surplus contactors supply a total of 4 amps to the Starter Relays. I've looked at welding relays rated for 250 amps and they really don't look that substantial so I'm confident that Two of these Starter Relays in parellel should give me maximum of around 250 amps at around 60% duty cyle. Works very nice so far and if they dump early..oh well you get what you pay for!
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  • #2
    A definite purpose contactor rated for our feeder can be had for under $75 on .
    Chief slag chipper & floor sweeper
    Ironwood Artistic