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Probably they won't work for ETs. AC relays have a lower coil resistance and inductance because the AC impedance of a coil is higher than the DC impedance.
Most 110VAC relays work well on about 24VDC. So these 24VAC relays would maybe work on 6VDC or so. You could test them by seeing at what voltage they pull in using a variable DC power supply. Harry Landis > Date: Mon, 27 Jun 2011 18:59:32 -0500 > From: bobbrandon frontiernet net > To: Walter Konstanty ge com; elec-trak cosmos phy tufts edu > Subject: Re: (ET) 24V relays > > I just happen to have about a dozen P&B relays I'm supposed to sell for a > guy. These are in clear cases. > New In original boxes > 1 3/8 square X 2.5 long include pins. > Model KRP14 AG > 3PDT 10 A > 24VAC coil. Will they work on 24 DC as well? > These are 11 pin relays; I only have 2 bases (so far) > There are (5) 5A ones also > Model KRP14 A > I will sell these cheap if they will work. > Make offer ? > Bob Brandon > > Konstanty, Walter (GE Energy Services) > > > Guys, > > I received several email replies about details of the relay conversion > > so here's a mass answer..... > > > > - Replacing original finger relays > > 24 volt DC relays can be used but you need to add a resistor because > > they are connected to 36 volts on the tractor. Relay contacts should be > > DPDT and rated 10 amps. The resistor you put in series with the coil > > needs to be approximately 1/2 of the coil resistance (use 2 watt size). > > Here's an email from 2005 on this subject: > > I replaced my dashboard relays with the following items. They are from > > MCM InOne (electronics distributor) in Ohio. The catalog is on-line. > > relay 28-4950 $6 each DPDT 10 amps > > socket 28-4951 $7 each > > > > The relays can be mounted in the sockets of course- they are small and > > narrow, good fit. The relays also have upside-down mounting ears so you > > can mount them "terminals up" and use the existing push--on connectors. > > My connectors are weak and corroded so I used the sockets. > > These relays are 24 volts 600 ohm coils. I used a 270 ohm/ 2 watt > > resistor in series with each coil. They operate fine and do not get > > nearly as hot as the old relays. > > > > Then, no more relay issues. Potter & Brumfeld make similar relays > > which are the ones I used. > > > > - Battery Chargers > > Soneil chargers are mentioned and used quite a bit. A while ago > > someone described the Japlar-Schauer charger and I bought one and use it > > with an SB-50 plug (small version of an electric fork lift plug for > > quick disconnect available at forklift/Industrial stores) and it works > > well for my tractors. That way I don't haul the charger around either. > > Website is: > > http://www.battery-chargers.com/chgrpic.htm > > > > ...Walt > > > > -----Original Message----- > > From: Konstanty, Walter (GE Energy Services) > > Sent: Friday, June 24, 2011 9:41 AM > > To: David Roden (Akron OH USA); elec-trak cosmos phy tufts edu > > Subject: Re: (ET) GE Elec Trak > > > > Guys, > > 28 years ago I removed the finger relays from my E-15 and put in 24 > > volt Potter Brumfeld plug in socket relays and have not touched the > > control since. At that time I cleaned and tightened the circuit board > > contacts and any other suspicious connections. It runs as good as new > > with zero maintenance. Added a "smart charger" since with SB-50 plug to > > use on both ET's I have. The E-20 was converted to a METI repower kit > > using a GE programmable golf cart controller and while it doesn't regen > > it provides flawless operation and smooth acceleration. The original > > finger relays were the biggest issue with the controllers - change them > > out and it will run forever unless you want to modernize with a new > > control. > > Keep em running !! > > > > ...Walt > > > > -----Original Message----- > > From: David Roden (Akron OH USA) [mailto:etpost drmm net] > > Sent: Friday, June 24, 2011 12:39 AM > > To: elec-trak cosmos phy tufts edu > > Subject: Re: (ET) GE Elec Trak > > > > Can't help you on the solar part, but I can tell you that I fitted an > > Alltrax controller to my E15 a few years ago. I would never go back to > > the factory speed control. The Alltrax is buttery-smooth; I can move > > the > > tractor by centimeters. (As a note, there are other transistor > > controllers > > that can provide the same service, it's just that this one is configured > > for > > ETs.) > > > > It's also more reliable. Folks will tell you that the big advantage of > > the GE contactor controller is that it's easy to work on because it's so > > straightforward. They're right, and that's a good thing, because you'll > > be > > working on it a fair bit, if my experience is any indication. > > > > On the other hand, once you get the Alltrax installed, it JUST WORKS. > > > > When I had the GE contactor controller, I was forever fixing something, > > either a semiconductor on one of the cards or the burnt reversing relay > > contacts. The final straw came the blustery winter's day when I was > > plowing and had to reverse the tractor by raising the hood, lowering the > > relay panel, and pushing on the reverse relay. > > > > You can certainly rebuild or replace the various components of the GE > > controller, and that will probably improve its reliability. However, > > IMO it's not worth working on. If yours works, I'd say use it until it > > doesn't, and then rip it out and put in something that wasn't developed > > in the Apollo Space Program era. > > > > But as you'd expect there are plenty of opinions to the contrary here. > > ;-) > > > > > > > > _______________________________________________ > > Elec-trak mailing list > > Elec-trak cosmos phy tufts edu > > https://cosmos.phy.tufts.edu/mailman/listinfo.cgi/elec-trak > > > > _______________________________________________ > > Elec-trak mailing list > > Elec-trak cosmos phy tufts edu > > https://cosmos.phy.tufts.edu/mailman/listinfo.cgi/elec-trak > > > > _______________________________________________ > > Elec-trak mailing list > > Elec-trak cosmos phy tufts edu > > https://cosmos.phy.tufts.edu/mailman/listinfo.cgi/elec-trak > > > _______________________________________________ > Elec-trak mailing list > Elec-trak cosmos phy tufts edu > https://cosmos.phy.tufts.edu/mailman/listinfo.cgi/elec-trak |