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Re: (ET) 24V relays
It's generally not a good idea to use DC on an AC relay or vice versa.
A good article is here:
http://relays.tycoelectronics.com/appnotes/app_pdfs/13c3250.pdf
...Walt
-----Original Message-----
From: Bob Brandon [mailto:bobbrandon frontiernet net]
Sent: Monday, June 27, 2011 8:00 PM
To: Konstanty, Walter (GE Energy Services);
elec-trak cosmos phy tufts edu
Subject: Re: 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.
> ;-)
>
>
>
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