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What the heck is this attached to my generator?

Posted: Fri Oct 23, 2015 4:27 pm
by daveleast
Anyone know what the heck this thing is with the fins? My '65 was a fire service vehicle and has the original generator and this thing attached to it. :banghead
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Re: What the heck is this attached to my generator?

Posted: Fri Oct 23, 2015 7:55 pm
by digdoug
Flux capacitor? :thinking

Re: What the heck is this attached to my generator?

Posted: Fri Oct 23, 2015 9:04 pm
by WD
Selenium rectifier like on older Honda motorcycles. Runs AC accessories off of DC generators. Best guess anyway.

Re: What the heck is this attached to my generator?

Posted: Fri Oct 23, 2015 10:23 pm
by daveleast
Thanks WD! I think you're right. Did a little more searching and that is exactly what it is. I'm out of my depth, but from what I've read, these were used for auto charging systems before diodes became reliable, to support extra electrical gear like radios, etc. This article discusses them briefly and the Leece Neville generators http://www.allpar.com/eek/alternators.html

Re: What the heck is this attached to my generator?

Posted: Fri Oct 30, 2015 4:29 pm
by Cris
I was going to go with (multi slice) toaster.

Re: What the heck is this attached to my generator?

Posted: Tue Apr 05, 2016 12:32 pm
by PwrWgnDrvr
1. That is NOT a selenium rectifier!
2. Rectifier and diode is synonymous.
3. Rectifiers make AC into DC, NOT the other way around.
4. Diodes are ALWAYS integral with alternators, which make AC, NEVER used with generators, which make DC
5. That is NOT a factory generator/alternator in the picture - I cant tell which it is
6. Why is your battery on the passenger side?
7. Do u have 2 batteries?
8. If u do, that "finned" device is a common dual diode used to isolate the 2 batteries from each other so that they may both be charged by a single alternator/charger
9. All swepts came stock with alternators which have integral diodes to change the AC to DC. Generators went obsolete in the 50's.

Re: What the heck is this attached to my generator?

Posted: Tue Apr 05, 2016 3:19 pm
by daveleast
Thanks for the feedback, please see below

1. I'll defer to you and the other folks on this forum but it sure looks like the selenium rectifiers I've seen in pictures. I've found references to them being used on M37's and crash trucks so I'm not sure. I assumed it had something to do with rescue or radio equipment?
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5. According to the second owner, this is how the truck was set up when they bought it from a California fire department. I guess it could have been converted from an alternator to a generator at some point but I can't imagine why anyone would do that? Definitely a generator though. It also has a master electrical cutoff switch on the floor, similar to what you would find in a boat.
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6. Good question - that's how it was when I bought it.

7. Hasn't had two batteries since I bought it, but there is a tray on the driver side for a second one.

9. I wonder if generators would have been an equipment option for Power Wagons?

Re: What the heck is this attached to my generator?

Posted: Tue May 10, 2016 7:13 pm
by Mopower
Can we see the whole truck, please, the more pics the better, thx! ;-)

Re: What the heck is this attached to my generator?

Posted: Sun May 15, 2016 11:36 am
by daveleast
Sure, here's a couple more :-)
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Re: What the heck is this attached to my generator?

Posted: Sat Jun 11, 2016 11:14 am
by LuckyBaldwin
Nice pics! thanks for posting them. that's something i've never seen before. most bizarre.

"Generator Control Unit" = voltage regulator (see how it's rated at 14 volts), so might be used with an alternator. the unit looks pretty small for a 60 amp generator. maybe it's an early model alternator and that accordion is a selenium rectifier. you can hook a DVOM to the output and see if the voltage stays constant or oscillates between + and -. that would tell you which it is. if it turns out to be a generator, i'd go with the flux capacitor answer.

Re: What the heck is this attached to my generator?

Posted: Wed Aug 31, 2016 1:03 pm
by Kaegi
leece Neville is still around and can probably end you support material on the system. it is high quality stuff. I would keep it if working now. that cole hearsey switch is still widely available. too

Re: What the heck is this attached to my generator?

Posted: Sun Sep 04, 2016 10:55 pm
by PwrWgnDrvr
Vehicle generators make DC. Alternators make AC. Note in the pic of the generator it says ground is NEG. That indicates it is DC. All vehicle charging systems run at 14V in order to fully charge 12V batteries.

Re: What the heck is this attached to my generator?

Posted: Wed Nov 30, 2016 8:35 pm
by swptln
I'm with Terry,
That looks like a battery isolator, especially where the truck had dual batteries. Beit, a generator or alternator, probably had some type of 12volt system separate from the truck to operate some equipment on the back. The isolator's were used to isolate/dedicate the load to one battery, this way the truck would not have to be running to operate the equipment on the truck. One way to tell is, if there are no battery cables run between the two batteries, then it would definitely be an isolator for charging.
I had a bucket truck setup the same way, one battery was for the truck and the 2nd battery was for a gas generator/hydraulic pump to operate the lift and it also used the 2nd battery with a 12volt starter motor to operate the emergency hydraulic pump for the lift. It was also setup that you had to shut the truck off to operate the lift.