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Generator issue

Electrical issues
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1955fle
Posts: 173
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1973 FLH
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Generator issue

#1

Post by 1955fle » Fri Jul 02, 2010 3:03 am

Just rebuilt the 3 brush generator on my '55 FL. Replaced brushes and bearings, cleaned case, replaced oil deflector and drive gear. All went well. Installed it back on the bike. NO noise and charging at 6.84V. put the lights on and voltage drops and generator light on dash blinks. Adjust 3rd brush , no change. I followed the Harley service manual very carefully. What do you think I missed? Could I have connected the wires from the coils to the wrong brushes? What do you think?

-Carl



FlatHeadSix
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Re: Generator issue

#2

Post by FlatHeadSix » Fri Jul 02, 2010 4:33 am

1955fle wrote: Could I have connected the wires from the coils to the wrong brushes?-Carl
YES, or you have the shunt coil grounded. Please remember that the 2 field coils in a 3-brush unit are both different and they are also independent of one another. When the ignition switch is in the first position only one coil is working. The other coil only receives energy when you switch the lights on. You probably have the the wires in the right places but something is grounding out on the 2nd field coil.

let us know what you find.

mike

1955fle
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1973 FLH
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Re: Generator issue

#3

Post by 1955fle » Fri Jul 02, 2010 2:23 pm

Thanks for the reply. I did not remove the field coils from the case. Just changed the brushes and bearings and some outside parts. I will remove it and go through the testing that is in the manual. I will let you know how it goes. -Carl

hogboy52
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Re: Generator issue

#4

Post by hogboy52 » Fri Jul 02, 2010 3:26 pm

Before you take everything apart turn on the light switch and check to see if there is 6V. at the
shunt terminal (labeled switch?) on the generator. That is how the output is boosted. You can check it motor off. A short there would make a lot of smoke.

1955fle
Posts: 173
Joined: Mon Feb 26, 2007 10:50 pm
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1973 FLH
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Re: Generator issue

#5

Post by 1955fle » Fri Jul 02, 2010 6:01 pm

Thanks Hogboy52, that will be a good test. I am hoping this is not a big deal. The generator was working fine before I touched it this time. I have had it apart several times before to clean it, so I am familiar with what is inside. -Carl

1955fle
Posts: 173
Joined: Mon Feb 26, 2007 10:50 pm
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1973 FLH
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Re: Generator issue

#6

Post by 1955fle » Fri Jul 02, 2010 6:04 pm

I have never seen the generator light blink before. It was always either on or off.

RUBONE
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Re: Generator issue

#7

Post by RUBONE » Fri Jul 02, 2010 9:08 pm

I have never seen the generator light blink before. It was always either on or off.
If the light is blinking that indicates the points in the relay are opening and closing rapidly, either from a short somewhere or output spiking. Normally as they close to allow charging the light goes off and when the voltage drops they go back on. Sounds like something wired wrong in the generator causing this as well.
Robbie

1955fle
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1973 FLH
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Re: Generator issue

#8

Post by 1955fle » Tue Jul 06, 2010 3:16 pm

Took the generator apart again and believe that I had one wire connected wrong (which means actually 2 wires). Put it all together and got the bike started. The generator light stays on steady with the lights on or off. It appears that the generator is only putting out 5.34 V at the relay terminal, and when I stitch on the lights I get only 5.40 V at the switch terminal. I measured this with a multimeter with the pos lead on the terminal and the neg lead to ground. Is there a better way to measure the output? This was a simple rebuild where I only changed the brushes and a bearing. All worked fine before I touched it. Any suggestions on what I might have done wrong would be a great help.

_Carl

1955fle
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1973 FLH
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Re: Generator issue

#9

Post by 1955fle » Wed Jul 07, 2010 12:29 am

So I took the generator off of the bike again and ran the tests recommended in the manual. I have a reproduction manual so the pictures were pretty muddy. I took a wire and connected it to the positive side of a charged 6V battery. I connected the other end to the positive side of a digital multimeter and ran through the tests. I got no readings on the meter so I am guessing I did it wrong. Can anyone explain the process of connecting power to 1 lead of the meter and doing the tests. I have a manual so I don't need what the tests are, just how to connect up the meter.

Thanks in advance
Carl

Schwee
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Re: Generator issue

#10

Post by Schwee » Wed Jul 07, 2010 1:41 pm

A good test while the genny if off the bike.
Hook 6v+ to one terminal and 6v- to ground.
The genny should "motor", that is, spin (not real fast).
Repeat on each terminal. They are separate circuits.

I've seen lots of oldies wrap bailing wire around the two terminals so that the genny is ALWAYS putting out maximum amps (as if lights are always on). Rat stuff.

1955fle
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1973 FLH
Location: Mass

Re: Generator issue

#11

Post by 1955fle » Thu Jul 08, 2010 3:01 pm

I have ordered a new set of field coils. The coils that are in the generator are in tough shape and the wires coming out of one is very fragile. I hope this will solve the problem. is there anything I should think about installing the new coils. I know the clearances to the armature are critical. Is there a trick to installing them to make sure the spaces are correct?

-Carl

Bosheff
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Re: Generator issue

#12

Post by Bosheff » Thu Jul 08, 2010 4:50 pm

If they are good quality pieces, clearance should not be an issue if you are using a Genuine H-D generator case/frame. When assembled properly there will be a very slight drag felt when spinning the armature, but there should not be any grinding....bosheff

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