6 Volt Charging Problem

[motive]

Ran the battery down trying to restart my Speedster. Jumped it according to the accepted method and got it running. Since the battery was very low, the ammeter showed full charge as expected. As I continued to drive the car for a while on my way home, it remained at full charge and I began to notice a faint "electrical" smell entering the cabin. Shortly after this the ammeter rapidly went from full charge to slightly negative, showing a slight discharge. Made it home safely, started the car the next morning and it appeared normal at idle with a slight positive charge on the ammeter. BUT... as I increased engine speed the ammeter moved to full charge and rapidly dropped to the slightly negative position, never to return to the positive side again. Clearly it is not charging anymore. I tried connecting a voltmeter across the "Gen" and "Field" terminals of the genertor with the engine idling and observed no measurable voltage. I have not yet checked the generator brushes, but I removed the regulator cover and everything looked and smelled fine. Any comments or suggestions? Should I have seen voltage across the Gen and Field terminals? Any help will be greatly apreciated.

Mike with Speedster

[N8N]

test for voltage at the "gen" terminal to ground, should be somewhere around 7V running. If it is, say, 5.9 or thereabouts then your gen. is not charging. So you need to figure out why. Check for voltage between "field" and ground. Should be some small voltage. if none then your regulator is bad. if some voltage then it sounds like the gen. is bad, but to check for sure, while the engine is idling jump "bat" to "field" then you should get a high (greater than 6) voltage between "gen" and ground. If not then the generator is definitely bad. Leave lights, radio, etc. off while full-fielding or you will let the smoke out.

good luck

nate

--
55 Commander Starlight
62 Daytona hardtop

http://home.comcast.net/~njnagel

[motive]

Nate: Thanks for the help. I measured voltage from GEN to ground and got zero, FIELD to ground and got zero. So I'm thinking that the generator is dead. At least I now know where to start.

Mike with Speedster

[N8N]

What happens when you full field it? if there's no voltage on the field terminal it won't charge...

nate

--
55 Commander Starlight
62 Daytona hardtop

http://home.comcast.net/~njnagel

[Roscomacaw]

You'd better have a GOOD look at the connections on the back of the ammeter.[}]

Miscreant at large.

1957 Transtar 1/2ton
1960 Larkvertible V8
1958 Provincial wagon
1953 Commander coupe
1957 President 2-dr
1955 President State
1951 Champion Biz cpe
1963 Daytona project FS

[motive]

Mr. Biggs: Do you think that the smell was coming from the melting insulation on the wires to and/or from the ammeter and that the ammeter connections might have been loose/corroded and of high resistance? I'll be sure to check them!

Mike with Speedster

[Roscomacaw]

I can't be that specific from this chair. But obviously something was getting warmer than it should be. I'd damn sure check those connections before I ran the car again.

Miscreant at large.

1957 Transtar 1/2ton
1960 Larkvertible V8
1958 Provincial wagon
1953 Commander coupe
1957 President 2-dr
1955 President State
1951 Champion Biz cpe
1963 Daytona project FS

[motive]

I checked the ammeter leads and they look fine, no indication of melted insulation or overheating. With the engine idling, no voltage from GEN to GRND. Took off the generator band, cleaned the commutator, checked the brushes (which looked good), still no voltage from GEN to GRND. Removed the generator from the car and spun it on rapidly the bench with a socket and drill. GEN to GRND gave me < 1.0 volts, FIELD to GRND the same. I show continuity between GEN and FIELD, between GEN and housing, and between FIELD and housing. Shouldn't something be isolated. I'm not an electrical guy and this is my first experience with generators, so I'm not very informed. But I expected to see approx. 7.0 volts from the GEN to GRND when I spun it on the bench. Looks like this generator may have burned up during the extended high charging. I hate to throw parts at something, but I'm thinking a rebuilt generator and a new regulator may be the answer. Any recommendations for suppliers?

Thanks, Mike with Speedster

[55s]

Mike:

By correct way to boost, it would be positive to positive and negative to negative, regardless of the fact that the Speedster is 6V negative ground. In other words, the negative ground of the 12V car goes to the 6V negative terminal, and the positive 12V goes to the 6V positive ground. In any case, watch it, because I have had a 6V battery explode whan I boosted it.

If its any consolation, 6V starting is always slower than 12 V starting.

Besides looking for a short on the back of the ammeter, check the back of the starter switch (in the dash), the terminal block under the hood on the radiator, and the wiring coming out of the steering column for shorts. Also, make sure those 55 dash switches are turning on and off cleanly.

I don't think you have done anything to damage the generator. I'd try to get some local help to diagnose before spending money on spare parts.

Alternately, you should always have spares to keep your car going - so maybe now is the time to invest in spares - if the new set doesn't work, you'll have a spare. But it does sound as though you have a short problem to resolve first.

Goodluck.

Paul

[ceecab]

By correct way to boost, it would be positive to positive and negative to negative, regardless of the fact that the Speedster is 6V negative ground.

Except that a '55 is 6V positive ground-- including Speedsters

[Roscomacaw]

motive,

Without having a battery and voltage regulator "on the bench" as well, you're going to see very little voltage [:I] (like ONE volt.[)])
The voltage regulator looks at the output of the generator and then sends the field winding the appropriate amount of grounding to cause the generator to meet the demands of the electrical system. (The other end of the field circuit is connected to the Generator's A terminal and gets it's "hot" side there.) The field winding uses that metered ground to build a variable magnetic field. The spinning armature cuts thru that magnetic field and in so doing, produces the voltage that runs the electrical items on the car and charges the battery so that there's power to run things even when the generator's not spinning.
Consequently, without the regulator to send the field a signal, and without the battery to provide a load - you've gonna see a very minor voltage when just spinning the generator on the bench.
That you see anything AT ALL, is due to the fact that the steel core's of the field windings have retained some magnetisim from the time when said windings were energized. This residual magnetisim, minor tho it is, is enough to generate SOME voltage in the armature as it spins. Consequently, only one volt (or thereabouts) output.[V]

As to your question "shouldn't something be isolated" - the answer is no. Not in this generator. The field and the A terminal should read to the case. Not as zero ohms, but they will show a reading. This is due to how it's wired internally. Remove (unseat) the one brush that's connected (grounded) to the case. If you still have continuity with this bursh displaced/or removed, then you've got an internal short.

An alternator and a generator are actualy working in the same ways essentially. The difference is that the windings of the spinning armature of a generator become the stator (stationary ) windings of the alternator. The field windings (the stationary windings inside the generator's housing) of the generator are replaced by the rotor (rotating windings) of the alternator.

I'd like to ask if you've visually checked all the connections on the regulator. Tight?, no evidence of overheating?
Where is the battery cable from the battery's positive terminal grounded? Is it grounded to the engine or???[?]


Miscreant at large.

1957 Transtar 1/2ton
1960 Larkvertible V8
1958 Provincial wagon
1953 Commander coupe
1957 President 2-dr
1955 President State
1951 Champion Biz cpe
1963 Daytona project FS

[motive]

Jumped it positive to positve, negative to negative, touching the negative of the Speedster with the jumper cable only while the starter was cranking. There are no visible signs of shorted wires under the dash at the ammeter or the ignition switch, or at the ternminal block on the fan shroud. All connections at the regulator appear clean and solid. System was working perfectly until after the jump, when the high charge rate appeared to last longer than necessary to charge the battery. Battery still has charge after driving it home and it sitting about a week. Shows 6.1 across terminals.

Mike with Speedster

[motive]

Positive terminal of battery is grounded to engine using a heavy woven metal strap. There also is another much shorter grounding strap connecting the engine to the frame at the lower front right side of the engine. I tried removing the two brushes from the generator and still saw continuity with the housing although now there was measurable resistance across each terminal to the housing. Also removed the regulator and checked/adjusted point gaps etc. per owners manual. Everything was pretty close to spec. Re-installed everything, polarized generator, started her up and still no charging. Ammeter shows discharge that changes with load, so I know the ammeter is working. Just can't get it to show positive charge. Another item to mention, there are two small condensers (capacitors) in the system. One is mounted on the generator housing and is connected field terminal of the generator, the other is mounter on one of the regulator mounting bolts and is connected to the Battery terminal of the regulator. One may be for radio noise suppresion?, the other to stop arcing across the points of the regulator? Shop manual really doesn't show or mention these at all. No numbers on them that I can see. Although it's probably unlikely that these are involved, I'd still like to know what purpose they serve. Thanks And Happy New Year.

Mike with Speedster

[N8N]

I don't believe the suppression cap should be on the field terminal, rather it should be on the "A" terminal... but I doubt that is your problem. take it out of the system completely for now until you are done troubleshooting, that way if it is bad you will know it when you hook it back up

nate

--
55 Commander Starlight
62 Daytona hardtop

http://home.comcast.net/~njnagel

[motive]

I'll take it out of the system. One other quick question. With the ignition switch in the OFF position (key removed) I see battery voltage at the BATTERY terminal of the regulator. Is this normal or should I only see it when the ignition is in the ON position? Seems odd that it would remain hot all the time. I need a wiring diagram!

Mike with Speedster