52 l85

[Angelo]

New voltage regulator installed. All terminals cleaned and still charging at 18volts. Any one have a clue has a leece Neville generator on motor. Idols at 14 volts soon as into pedal goes to 18volt 

[mowerman]

Maybe you did not polorize the regulator that’s what we used to have to do years ago I can’t remember how to do it now but somebody else probably does …. But it sounds like you’re getting closer to success. Bob

[doubleclutchinweasel]

Polarizing was important. I think there are instructions out there. 

[mowerman]

I found some on YouTube, of course

[mowerman]

I have not done one in over 40 years. you have to take a screwdriver and click two post together? I don’t remember which 2 

[High Binder]

Being a 52, I'm assuming it's a positive ground. I would load test my batteries before I did anything else. Bob is correct about crossing the points on the regulator. It's a simple task but I ruined two regulators crossing them.

[Geoff Weeks]

Battery to Armature.  Not to field. If in doubt, connect a jumper cable to the battery hot and touch the other end to the heavier of the two terminals on the genny.

[Geoff Weeks]

that said, polarizing will have no effect on the voltage setting. SO either you have a wiring problem, a regulator problem or a grounding problem. A regulator can only act on the voltage it "sees" so if the ground path is poor, it will "see" less voltage.

I may be wrong, but didn't most have Delco generators?

 Lets get a picture of what you are working on.

 

[Geoff Weeks]

BTW this is the 2nd thread on the same problem in the same section. don't start multiple threads on the same problem it gets confusing.

[Angelo]

It has a Leece Neville generator. 

Regulater has 

on left side it says from top to bottom 4 posts

Ign

G
 

Gen 

 

F

on right side it has B post

all is Hooked the same way old one was. I had many miles on it problem free until this issue 

Edited October 2, 2023 by Angelo

[Geoff Weeks]

 

OK, this is going to be hard to sort out. It isn't the typical truck charging system, it is firetruck special.

 Not having the schematic on hand this is what I can say

B goes to the ammeter or battery

F to field

Gen to armature

ign to switched ign feed

You didn't mention the terminal at the top

G may or may not be ground

A regulator is only as good as its connection to what it is regulating. If it is not making good connections it can't regulate.

 I still want a pic of the generator and associated wiring, it may still be an alternator, as I have a L/N set-up that looks very similar.

 You really are going to need someone who knows this type of equipment. Most truck people have no clue.

 With the ign feed, I suspect this is an alternator set-up with remote rectifier (big finned thing with three heavy wires coming from the "generator" and one heavy wire to to regulator)

The early remote rectifier systems are weird in that the regulator dis connects them from the battery when the ign is off.  This is how mine is set-up, it is similar but not exactly the same. It is a 100 amp L/N 6 volt alternator from the 50's.

 More pictures are needed.

[Angelo]

I believe this is rectifier 

[Angelo]

I’ll lift hood and take a few more pictures tomorrow. I’m wondering if the ground wire between gen and regulator is maybe bad?

[Geoff Weeks]

Yes, that is a rectifier. and so it does have an early alternator system. Not a generator (dynamo). Yes, as I stated before, it could have a bad connection between the generator and regulator.  Body could have a bad ground between it and the chassie, or frame.

 Technically, anything that produces DC is a generator, while anything that produces A/C is an alternator. But in automotive terms the two get mixed up a bit.

[mrsmackpaul]

Does this have a socket to plug power in to keep it charged when parked in a fire station?

I don't know about fire trucks but have been sent to repair power supplies etc at ambulance stations in Australia and they have a lead to plug the ambulance in

This must be unplugged before the ambulance starts

Am wondering if this rectifier is similar part of the charging to the ambulances I have worked on and nothing to do with normal charging off the fire trucks generator

Not knowing my ass from my elbow about fire trucks I can't really advise

I can only imagine they are built to be able to idle for hours on end and run on full power the same 

No matter now, all we for sure is it's charging but not regulating

 

As far as polarizing goes, I'm pretty sure thats done make it either positive ground or negative ground

 

Paul

[mowerman]

I am also thinking ground somewhere issue could probably drive you crazy good luck … bob

[Geoff Weeks]

Paul,

Early alternator systems (talking 40's and 50's) had the rectifiers mounted separate a they didn't have high power diodes at that time. Remember, this is a time when most semi trucks had 50 amp generators.  Fire trucks, and tow trucks could be fitted (at great expense) with L/N's alternators, Not only did they provide much more current, but could do so at lower speeds. Important for E vehicles.

 I have a 6 volt 100 amp set-up that is similar to the one here but not exact.  Because the rectifiers were external, they were not kept connected to the battery like a modern alternator. The big regulator had a main relay inside that closed when the ign was turned on, and also a voltage regulator. (current regulation is not needed on an alternator as the winding are self regulating).

 The rectifiers have nothing to do with shop power, they are for the engine alternator.  For some special application remote rectifiers are still used. My unit has the same rectifier set up.

 If he just wants to "get it running" then the whole system can be replaced by a modern (one wire) alternator.

 Alternators DO NOT get polarized, and in most cases generators don't lose there polarity, so only need to be polarized when a new unit is placed in service or an old unit is used on a different ground vehicle.

 Some fire trucks used the 3 phase output via transformers to provide 120 volt power for lights and universal motors for saws and the like.

 I'll have to look at my regulator and see if it is enough similar to his to be sure of the connections. Fairly sure the problem will come down to voltage drop in one of the circuits, either the ground or power side, or the field not being fed from the regulator like it should be, but cross shorted to the output wires some how. Without either being there or good photo's I can't tell what the problem is.

 Part of what sent this down the wrong road was saying it was a generator, that lead to the whole polarizing issue which has nothing to do with this. On the 1st thread started, I mentioned it might be an alternator and asked for pictures, which were not provided at that time.

[High Binder]

This is interesting to me because I have a truck doing the same thing. I know my batteries are not real good, due to sitting, and I assumed the generator was trying to fully charge the batteries since all I do is throw a quick charge on them prior to starting. This makes me think in a different direction.

[Geoff Weeks]

Be aware the Selenium rectifiers used can "pop" releasing toxic vapor, which is why, I am looking to replace mine with modern diodes.

https://en.wikipedia.org/wiki/Selenium_rectifier

See above for more info

[Geoff Weeks]

In case anyone cares:

Here is my 100 amp 6 volt unit, a bit different from his 100 amp 12 volt regulator. Output from the alternator is 3 phase delta wound stator. A three phase bridge rectifier that is isolated from the trucks wiring when the engine is off, via the big relay under the reg cover. On mine the voltage regulator controls the hot side of the field, but the alternator itself could be regulated by either hot or ground side.  Note the grounding tab on the last picture to ground the rubber mounted regulator (common at the time to isolate the reg from the truck to reduce vibration induced problems.

 Rectifier is isolated when the truck is off to prevent leakage back through the windings and for safety, in case something falls on the rectifier when someone is working on the engine.

 Mine came from a 40's GMC tow truck.

 

[mechohaulic]

I'm probably out in left field on this one but with all the talk of generators/ alternators / rectifiers, grounds being a possible situation creator;  I haven't seen a mention of :: did anyone check the batteries INDIVIDUALLY  (load test ) ;;OR do a cell test (hydrometer ???)  checking to see if a bad cell is causing a generator/alternator to over charge thinking system low ???  lets  get this thing rectified soon  for sake of a firetruck. 

[Geoff Weeks]

Not so far in left, it depends on how well the regulator can clamp a light load. Normally, alternators of this size came about after the electronic regulators. Smaller output units, the battery can stabilize the highs and lows, Mechanical regs  were primarily used when cars had 37- 45 amp units and trucks were no bigger than 60 amps. 

100 amps, with a mechanical reg and resistor cards, were rare. I have not had the 100 amp 6 volt unit up and running on a vehicle so I don't know how well it clamps the voltage on a light load.

 That said 18 volts is way above the 14- 14.2  set point.  I would expect it to be able to clamp better than that.

 A short in the field lead could burn a resistor card in the regulator and permanently damage the regulator. Finding replacement resistors would be hard.

 All that said, I wouldn't want the selenium rectifiers. That is what holding mine up/ I want to replace with modern diodes. Modern L/N diode packs would work well, but need to be cooled, so I need to fit them, isolated from case, in the air intakes on the back so cooling air gets drawn over the diodes. Just getting the time to get it done.

[Angelo]

The 2nd picture has two wires off back. One goes to rectifier which I believe was a ground to it, is the other the field wire? The rectifier wire was in bad shape so I made a new wire in its place

[Angelo]

If the other is field wire I will replace that too it’s pretty funky and looks like someone patched it a few times 

[Geoff Weeks]

The two small wires on the back are field wires. One should go back to the field terminal on the regulator.  Because your regulator is not identical to mine, I can't be sure

  where on the rectifier you connected the other will make a big difference. 

If i had to guess, I would guess the one field wire not connected to the regulator would go to ground, but without seeing the regulator and tracing out how it works, I can't be sure.

 The simplest course of action would be to replace with a modern "one wire" alternator, and do away with the troublesome rectifier and divorced regulator. It depends if you want period correct or not.

 You need someone who understands the system to guide you. This kind of work is very hard to diagnosis over the internet