The Ford Barn

Mart · 04-01-2018, 11:40 AM

On my 41 pickup I have a no charge problem. I have a 12v neg earth setup. I rebuilt a 12V generator into a flathead endcase and used the flathead pulley from a 01A 6v generator. I used the 12V armature and fields from the 12v unit. I tried both a good known regulator and a brand new regulator and it behaved the same. It will not start to charge until about 1500 rpm. This is no good as it equates to about 40 mph in top.

The generator has been polarised.

I borrowed the generator from my coupe (12V Lucas flatty) and it works great, charging from just above idle.

So the question is, where do I start to investigate why my converted unit does not start to charge until the revs are so much higher?

I have 3 cars and two working 12V generators so I do need to get this sorted out. I have another converted unit that I shelved because of the same problem.

Any ideas?

Mart.

Edit: I have added a video here: https://youtu.be/3iC6ZiWtho8 Not of the original problem, but after a go at reworking the converted generator.

M.

jimvette59 · 04-01-2018, 11:50 AM

Are the pulleys the same diameter on both generators ?

Mart · 04-01-2018, 12:01 PM

Well, the converted one has the pulley from the 6V generator, stock for a 40, so it should be ok, but I do see your point. I just went out and measured and they are both 3.7" or thereabout. So the charge / no charge situation can't be down to pulley diameter.

Thanks for the input, though.

Mart.

flatheadmurre · 04-01-2018, 12:05 PM

I would check the armature...with a 6v armature you get this kind of behavior.

Mart · 04-01-2018, 12:22 PM

Any suggestions as to how I can determine if the armature is 6V or 12V? It came from a y block generator, which (as far as I could tell) had 12V field coils, but I could have got that wrong.

Thanks for the suggestion.

Mart.

Kurt in NJ · 04-01-2018, 12:51 PM

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check polarity of fields ---one has to be "north"--you can do it from outside, only put compass close when power is on (field energized) or you can change compass
with armature on growler measure amp output of armature commutator bar to bar, always same place, but rotate armature to next bar---most generator will make around 15 amps(ac amps on growler)----even a jumper wire and compare sparks
does the commutator coloring look the same all around ---or do one or 2 bars look different

flatheadmurre · 04-01-2018, 01:23 PM

Quote:

Originally Posted by Mart

Any suggestions as to how I can determine if the armature is 6V or 12V? It came from a y block generator, which (as far as I could tell) had 12V field coils, but I could have got that wrong.

Thanks for the suggestion.

Mart.

Fields are easy to sort if they are 12v should be twice the resistance of the 6v ones.
Armatures sometimes got mismatched while rebuilding or someone in the past upgraded the generator to 12v by only swapping the fields.
Check the wire size of the armature 12v are thinner wires.

Mart · 04-01-2018, 04:23 PM

I don't have access to a growler, so I'm stuck with what I can do without one.

Does the thinner wire scenario hold true for the fields too? I'll pull it apart tomorrow and see if I can see anything obvious.

Mart.

flatheadmurre · 04-01-2018, 04:31 PM

The fields are easy to check for resistance with a multimeter no need to check wire size.

Mart · 04-02-2018, 07:57 AM

Update: I grabbed a Y block generator and stripped it down. I cleaned up the commutator and ran a ground down hacksaw up the insulators between the commutator segments. I radiused the brushes to the commutator.

I pulled the previous generator apart and and fitted the guts from the latest one into the flatty front housing and put the pulley on. I made a small spacer washer to fit behind the bearing as the built in spacer on the front of the commutator did not seem as long as on the previous one. Once more having a lathe proves indispensable.

Anyway, I hooked it all up and tried it. Initially it gave a big negative kick when it tried to charge, so I polarised the fields. to do this I detached the field wire at the regulator and flashed it a few times onto the bat terminal.

It did then start charging and seems to be charging at around 1000 rpm. It might be that as the brushes bed in better it will get a bit better, but I think that will be ok. I don't tend to do much night driving and there is not that much electrical equipment.

On a side note I noticed the idle was quite slow, so I turned that up a bit. I then noticed the mixture was a bit lean on one side of the carb and fiddling with the mixture screws smoothed it out nicely and I then had to slow down the idle as it seemed too fast . As I had the timing light hooked up, I checked the timing and it was at tdc at idle, so I bumped that around so it is now at about 4 or 5 degrees at idle.

So I now have a working generator that appears to be charging all right and I have also done a bit of a tune up, so good progress made.

Mart.

Anteek29 · 04-02-2018, 09:38 PM

Mart...we appreciate your update & status. You've made commendable progress!

Mart · 04-03-2018, 12:27 PM

I just put together a video from when I was working on the truck. I am trying to get the hang of a new editing software, so bear with me.

https://youtu.be/3iC6ZiWtho8

Mart.

Mart · 04-09-2018, 03:06 PM

Update to the update. I took a known 12V Y block generator from a known vehicle and rebuilt it into the Flatty front plate and pulley. It performed really well, just as good as the Lucas unit which outperformed both my previous attempts at a 12V conversion. The difference with this one is that I left the commutator and brushes untouched. I'm now pretty sure the bedding of the brushes to the commutator is a major part of the generator performance.

If you like dimly lit unscripted shaky videos check out this one:

https://youtu.be/_soxhcbN6Bs

Not sure exactly where I am going with this now, but I might give the previous incarnations another try but run them longer to see if the performance picks up with use.

Mart.

04-01-2018, 11:40 AM	#1
Mart Senior Member Join Date: May 2010 Location: Solihull, England. Posts: 8,747	Generator. What should I look at first? Now with video! On my 41 pickup I have a no charge problem. I have a 12v neg earth setup. I rebuilt a 12V generator into a flathead endcase and used the flathead pulley from a 01A 6v generator. I used the 12V armature and fields from the 12v unit. I tried both a good known regulator and a brand new regulator and it behaved the same. It will not start to charge until about 1500 rpm. This is no good as it equates to about 40 mph in top. The generator has been polarised. I borrowed the generator from my coupe (12V Lucas flatty) and it works great, charging from just above idle. So the question is, where do I start to investigate why my converted unit does not start to charge until the revs are so much higher? I have 3 cars and two working 12V generators so I do need to get this sorted out. I have another converted unit that I shelved because of the same problem. Any ideas? Mart. Edit: I have added a video here: https://youtu.be/3iC6ZiWtho8 Not of the original problem, but after a go at reworking the converted generator. M. Last edited by Mart; 04-03-2018 at 12:55 PM.

04-01-2018, 11:50 AM	#2
jimvette59 Senior Member Join Date: Jun 2010 Location: Perry OH Posts: 1,330	Re: Generator. What should I look at first? Are the pulleys the same diameter on both generators ?

04-01-2018, 12:01 PM	#3
Mart Senior Member Join Date: May 2010 Location: Solihull, England. Posts: 8,747	Re: Generator. What should I look at first? Well, the converted one has the pulley from the 6V generator, stock for a 40, so it should be ok, but I do see your point. I just went out and measured and they are both 3.7" or thereabout. So the charge / no charge situation can't be down to pulley diameter. Thanks for the input, though. Mart.

04-01-2018, 12:05 PM	#4
flatheadmurre Senior Member Join Date: Apr 2015 Location: Sweden Posts: 3,045	Re: Generator. What should I look at first? I would check the armature...with a 6v armature you get this kind of behavior.

04-01-2018, 12:22 PM	#5
Mart Senior Member Join Date: May 2010 Location: Solihull, England. Posts: 8,747	Re: Generator. What should I look at first? Any suggestions as to how I can determine if the armature is 6V or 12V? It came from a y block generator, which (as far as I could tell) had 12V field coils, but I could have got that wrong. Thanks for the suggestion. Mart.

04-01-2018, 12:51 PM	#6
Kurt in NJ Senior Member Join Date: May 2010 Location: on the Littlefield Posts: 6,157	Re: Generator. What should I look at first? Sponsored Links (Register now to hide all advertisements) check polarity of fields ---one has to be "north"--you can do it from outside, only put compass close when power is on (field energized) or you can change compass with armature on growler measure amp output of armature commutator bar to bar, always same place, but rotate armature to next bar---most generator will make around 15 amps(ac amps on growler)----even a jumper wire and compare sparks does the commutator coloring look the same all around ---or do one or 2 bars look different

04-01-2018, 04:23 PM	#8
Mart Senior Member Join Date: May 2010 Location: Solihull, England. Posts: 8,747	Re: Generator. What should I look at first? I don't have access to a growler, so I'm stuck with what I can do without one. Does the thinner wire scenario hold true for the fields too? I'll pull it apart tomorrow and see if I can see anything obvious. Mart.

04-01-2018, 04:31 PM	#9
flatheadmurre Senior Member Join Date: Apr 2015 Location: Sweden Posts: 3,045	Re: Generator. What should I look at first? The fields are easy to check for resistance with a multimeter no need to check wire size.

04-02-2018, 07:57 AM	#10
Mart Senior Member Join Date: May 2010 Location: Solihull, England. Posts: 8,747	Re: Generator. What should I look at first? Update: I grabbed a Y block generator and stripped it down. I cleaned up the commutator and ran a ground down hacksaw up the insulators between the commutator segments. I radiused the brushes to the commutator. I pulled the previous generator apart and and fitted the guts from the latest one into the flatty front housing and put the pulley on. I made a small spacer washer to fit behind the bearing as the built in spacer on the front of the commutator did not seem as long as on the previous one. Once more having a lathe proves indispensable. Anyway, I hooked it all up and tried it. Initially it gave a big negative kick when it tried to charge, so I polarised the fields. to do this I detached the field wire at the regulator and flashed it a few times onto the bat terminal. It did then start charging and seems to be charging at around 1000 rpm. It might be that as the brushes bed in better it will get a bit better, but I think that will be ok. I don't tend to do much night driving and there is not that much electrical equipment. On a side note I noticed the idle was quite slow, so I turned that up a bit. I then noticed the mixture was a bit lean on one side of the carb and fiddling with the mixture screws smoothed it out nicely and I then had to slow down the idle as it seemed too fast . As I had the timing light hooked up, I checked the timing and it was at tdc at idle, so I bumped that around so it is now at about 4 or 5 degrees at idle. So I now have a working generator that appears to be charging all right and I have also done a bit of a tune up, so good progress made. Mart. Last edited by Mart; 04-09-2018 at 03:15 PM.

04-02-2018, 09:38 PM	#11
Anteek29 Senior Member Join Date: Dec 2014 Location: Santa Maria, CA Posts: 985	Re: Generator. What should I look at first? Mart...we appreciate your update & status. You've made commendable progress! __________________ Alan 1929 Special Coupe 1941 Pick-Up 1955 Victoria

04-03-2018, 12:27 PM	#12
Mart Senior Member Join Date: May 2010 Location: Solihull, England. Posts: 8,747	Re: Generator. What should I look at first? I just put together a video from when I was working on the truck. I am trying to get the hang of a new editing software, so bear with me. https://youtu.be/3iC6ZiWtho8 Mart.

04-09-2018, 03:06 PM	#13
Mart Senior Member Join Date: May 2010 Location: Solihull, England. Posts: 8,747	Re: Generator. What should I look at first? Now with video! Update to the update. I took a known 12V Y block generator from a known vehicle and rebuilt it into the Flatty front plate and pulley. It performed really well, just as good as the Lucas unit which outperformed both my previous attempts at a 12V conversion. The difference with this one is that I left the commutator and brushes untouched. I'm now pretty sure the bedding of the brushes to the commutator is a major part of the generator performance. If you like dimly lit unscripted shaky videos check out this one: https://youtu.be/_soxhcbN6Bs Not sure exactly where I am going with this now, but I might give the previous incarnations another try but run them longer to see if the performance picks up with use. Mart.