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View Full Version : Converting a RFC-23A foot pedal



xiqtmw
12-01-2015, 05:15 PM
I recently received an old Miller RFC-23A from a friend. Found the spec and tested the cont and resistance to be good. The pedal is also in great shape. I've got an older Lincoln Square Wave that uses their standard 10k pot (6pin) pedal. How feasible would a conversion be? I understand the RFC-23A uses a 130w 15ohm resistor. My Googling came up that the Lincolns run a much lower, something about 2w, through the pedal.

mike837go
12-01-2015, 05:26 PM
The Lincoln needs Zero to 10,000 ohms signal.

The pedal you have goes from zero to 150 ohms.

Can you rig a locomotive to mow your lawn? Yes, but is it worth it?

soutthpaw
12-01-2015, 05:38 PM
Sell it and buy the right pedal. That pedal is worth$100-150 used.

DaveKamp
12-02-2015, 07:56 PM
I have a Lincoln pedal with 10k pot and switch... OTH I don't remember the model number, an Amptrol something like 817? 870? in physically good condition. Would you be interested in a trade?

xiqtmw
12-03-2015, 08:26 AM
The Lincoln needs Zero to 10,000 ohms signal.

The pedal you have goes from zero to 150 ohms.

Can you rig a locomotive to mow your lawn? Yes, but is it worth it?

Sometimes, you never know what people have done. It's amazing the work people do and are willing to share, which you'd never know until asking. I asked an EE and, like you implied, you'd wind up investing more money before considering time vs. just doing a sale and trade.

Worth it? Considering no easy solution, it is not for me.

The only reason I asked is I really like the weight and feedback on this pedal. It's heavy so it stays in place. the bottom lip keeps your foot where it should be. I can't say the same about my K870, even after replacing the spring on the inside.

xiqtmw
12-03-2015, 08:39 AM
I have a Lincoln pedal with 10k pot and switch... OTH I don't remember the model number, an Amptrol something like 817? 870? in physically good condition. Would you be interested in a trade?

Contacted via PM. You don't happen to have a 10k hand control/amptroll? I'm interesting in trying one out. I've got a K870 but have fixed various parts a number of times already, including having to splice off about 8' of the cable because of shorts. Sadly, it's $5 in electronics in a $20 case but even just a new 20' (nothing but 18/5 or 22/5) cable fetches $120 from their old, new stock suppliers.

DaveKamp
12-03-2015, 09:28 AM
Contacted via PM. You don't happen to have a 10k hand control/amptroll? I'm interesting in trying one out. I've got a K870 but have fixed various parts a number of times already, including having to splice off about 8' of the cable because of shorts. Sadly, it's $5 in electronics in a $20 case but even just a new 20' (nothing but 18/5 or 22/5) cable fetches $120 from their old, new stock suppliers.

I DID... but passed it on to a friend who needed one some time ago, sorry...

When you work on stuff like this, oftentimes, the original manufacturer is the best source of parts... and other times, it's the WORST... that cable is much less expensive when sourced elsewhere.

Turns out my K870 is labeled as a 25K unit (old age comes early I guess). I don't know wether your welder cares if it's 10K or 25k... you'll hafta investigate that... but if it's picky, I've got a Linde unit, also 25k, built heavy like the RFC-23A, uses a novel rack and pinion to a standard industrial potentiometer, and I have some 10K's around, emailed you photos of it. I'll swap it to a 10k pot if you'd like that one.

"MAKING" things work, is not so much about using a locomotive to mow your lawn, as it is, realizing wether your locomotive is readily adaptable to do so. I have a friend who uses a locomotive to mow his lawn... and heat his buildings, power lights, charge batteries, compress air, make microwave popcorn, run a 100-ton bridge crane and spin a 730,000lb steam engine display... the locomotive is on semi-stationary display, and it's generator is perfect for charging storage batteries running inverters that power his museum. It's a small locomotive... around 600hp switcher, originally with two Cummins sixes, one was taken out years ago... 24v start/run... originally 72v battery racks were re-configured to 24, which matches his 5kw inverter nicely. Since all the pieces of his program 'fit', he uses it as such. Heating oil gets delivered to the loco, and all his power comes from that loco. If it was a different locomotive... say... a SD30MAC, it wouldn't be as sensible... so many issues, it's just not as easy a match.

The RFC-23A isn't easily adaptable, one would have to either come up with a different resistor (it's a specially-made wirewound), or re-engineer the linkage completely to go to some other type of standard pot. The Linde that I have, already uses a standard pot, so it's a shoe-in for conversion.