Lightly Glowing Generator Light--Normal?

Electric Generator Light

All Panhead related topics
Post Reply
andyinlz
Posts: 56
Joined: Fri Jan 13, 2012 11:42 pm
Bikes: 1967 FLH
1959 FLH
Other H-Ds
Been thanked: 2 times

Lightly Glowing Generator Light--Normal?

#1

Post by andyinlz » Wed Jul 11, 2018 2:13 pm

New-to-me 1959 Pan. Fully charged new 6v HD battery. New old stock Accell regulator. Flashed generator. Stock 6v 2 brush setup and original wiring. Likely the original brushes in generator and bike is 21K miles from new.

The generator light turns out immediately and fully upon starting and stays out at idle. Voltage (measured across battey terminals) goes up to about 6.9 volts at idle.

However, as RPMs increase, generator light glows slightly, and this increases with RPM and increases further with headlight on, high beam turned on, and glows a bit more yet when spots turned on. The only non-stock additional lighting is two bullet lights under the seat that go on when the headlight is operational. Glows a bit more when rear brake applied (forgot to test consequences of turn signal usage but have electronic flasher so additional draw should not be too much).

Is this glow--say a maximum 30% when compared to when the generator light is fully lit when ignition is initially turned on--normal?

The only part I haven't been into yet is to remove and restore the generator and install new brushes.

Any thoughts? Is this subtly RPM-increasing glow normal or should the generator light be fully extinguished at all times and RPMs after starting?

I would like to make about a 200 mile round trip this weekend to the Panhead Reunion in MIL and would hate to run out of juice before arriving home.

Thanks in advance for your thoughts and experience.



RooDog
Posts: 135
Joined: Tue Oct 31, 2017 1:00 pm
Bikes: 1950 Resto-Mod Panhead, 1968 90", 5 Speed Shovelhead, 1984 Evo
100" Bagger
Location: Knoxville, Tennessee
Been thanked: 6 times

Re: Lightly Glowing Generator Light--Normal?

#2

Post by RooDog » Wed Jul 11, 2018 3:25 pm

This bike is "new to you" so I would most defiantly check the brushes AND their springs. I have had a spring go bad but still got charging output, enough to get back home, but I was lucky that time. Trust the light and not your luck..... I also run a perminantly installed volt meter on my scooters and it has saved my ass more than a few times....
Best wishes.....RooDog

awander
Site sponsor
Site sponsor
Posts: 1226
Joined: Fri Sep 21, 2007 3:03 am
Bikes: '52 FL
'64 FLH
Has thanked: 3 times
Been thanked: 53 times

Re: Lightly Glowing Generator Light--Normal?

#3

Post by awander » Wed Jul 11, 2018 4:39 pm

On a '59(if wiring is stock), the Generator light is wired between the output of the generator, and the battery voltage.

If there is an appreciable difference between the generator output and the battery voltage, the light will glow.

It sounds as if your generator/regulator is not working correctly, and as you add load(lights etc), the generator output is falling.

You can measure the voltage across the generator light by using a voltmeter between the BAT and GEN terminals on the regulator.

You can also measure the generator output voltage directly with a voltmeter between Ground(frame) and either the Generator "A" terminal, or the regulator GEN terminal.

The problem could be in the generator, the regulator, or the wiring.

andyinlz
Posts: 56
Joined: Fri Jan 13, 2012 11:42 pm
Bikes: 1967 FLH
1959 FLH
Other H-Ds
Been thanked: 2 times

Re: Lightly Glowing Generator Light--Normal?

#4

Post by andyinlz » Wed Jul 11, 2018 5:01 pm

Thank you both---I hate to dig into the generator due to lack of time/parts (but hate more to come home on a trailer).

I am also aware of the measurement points highlighted above and have the appropriate tools.

So, a glow is not acceptable?

As it is a result of generator/battery voltage variance, might it also glow due to an overcharging generator? Just wondering, as I have no other 2 brush experience (other bikes older or newer).

Thanks in advance.

awander
Site sponsor
Site sponsor
Posts: 1226
Joined: Fri Sep 21, 2007 3:03 am
Bikes: '52 FL
'64 FLH
Has thanked: 3 times
Been thanked: 53 times

Re: Lightly Glowing Generator Light--Normal?

#5

Post by awander » Wed Jul 11, 2018 5:14 pm

Correct, it could glow because the generator output is lower than the battery(as it is designed to do), but it would also glow if the generator output is higher than the voltage at the battery.

If the generator voltage drops below 6.3V or so, the regulator has a cutout relay which is supposed to disconnect the gen from the battery, so that the battery doesn't drain through the generator. The difference in voltage between the generator output and the battery voltage is what you will see. In the normal case, the generator voltage will be lower than the battery voltage when the cutout relay is open. On the other hand, if the cutout relay is adjusted to close at too high a voltage, then the generator may be putting out higher than battery voltage with the cutout open.

If the Generator voltage is above 6.3V, the cutout relay closes, and connects the generator to the battery. At that point, the generator voltage is applied to the battery, so generator voltage and battery voltage are equal, and the light should not go on.

If the generator is putting out too high a voltage, I would suspect a problem(s) in the regulator. The regulator adjusts the generator voltage output by varying the current in the generator field coils.

andyinlz
Posts: 56
Joined: Fri Jan 13, 2012 11:42 pm
Bikes: 1967 FLH
1959 FLH
Other H-Ds
Been thanked: 2 times

Re: Lightly Glowing Generator Light--Normal?

#6

Post by andyinlz » Wed Jul 11, 2018 6:13 pm

Thanks--that is what I suspected--the light going on (likely fully) due to undercharging from the battery when the relay opens. And also going on due to "overcharging" (perhaps varying in the intensity of the light's glow due to the amount of "overcharging").

I will measure a bit more and see if I can get my hands on brushes, springs, etc. before Saturday.

awander
Site sponsor
Site sponsor
Posts: 1226
Joined: Fri Sep 21, 2007 3:03 am
Bikes: '52 FL
'64 FLH
Has thanked: 3 times
Been thanked: 53 times

Re: Lightly Glowing Generator Light--Normal?

#7

Post by awander » Wed Jul 11, 2018 6:50 pm

The light will only go on n an "overcharge" situation(generator voltage higher than battery voltage) if the Regulator cutout relay is defective or adjusted incorrectly.

I'd be looking at the regulator first-what voltage does the cutout relay close on? And what voltage causes it to drop out?

andyinlz
Posts: 56
Joined: Fri Jan 13, 2012 11:42 pm
Bikes: 1967 FLH
1959 FLH
Other H-Ds
Been thanked: 2 times

Re: Lightly Glowing Generator Light--Normal?

#8

Post by andyinlz » Wed Jul 11, 2018 9:55 pm

All good Qs....but I will start with an overhaul of the generator, brushes and springs first.

Seems only fair after 59 years.

And, this behavior is consistent over 2 different regulators--a used Delco Remy and a NOS Accell.

I will report back.

bangkokbob
Posts: 126
Joined: Mon Jan 27, 2014 3:46 am
Bikes: 94FLSTN
63FLH
Has thanked: 3 times
Been thanked: 2 times

Re: Lightly Glowing Generator Light--Normal?

#9

Post by bangkokbob » Thu Jul 12, 2018 1:47 am

Hi there.
I suggest you take the generator and your 2 regulators to an electrician that knows what he's doing.
He will need to have a growler and check gen output and for shorts in the armature.
Get both regulators set to spec. (7.2v) and you will be good for years to come.
It will be worth the price it costs.
Regards B.B.

Frankenstein
Posts: 369
Joined: Sat Oct 08, 2005 2:14 pm
Bikes: 37ULH,46UL,47EL(80"),65FL,61KH-WL-BSA hybrid,56square4,several 50's BSA 500 singles
Location: Interlaken, NY
Been thanked: 16 times

Re: Lightly Glowing Generator Light--Normal?

#10

Post by Frankenstein » Thu Jul 12, 2018 2:10 am

Seems like I've been there, but can't remember the cause for sure now. As you proved to yourself by using 2 regulators, it is likely the generator, and I seem to remember that it was a brush problem, losing good contact as rev's increased, decreasing output. commutator cleaning, brush cleaning and perhaps turning down the commutator if it is quite irregular should solve the problem. Armature most likely doesn't have shorts or opens, but as others said only a growler is the true arbiter of an armature's health.
Good Luck
DD

john HD
Moderator
Posts: 3676
Joined: Sat Aug 20, 2005 7:24 pm
Bikes: '42 WLA X 2, '55FL, '93 Ultra Classic, '91 Fatboy, '97 883, '71 Suzuki Duster 125, '83 GPz 750.
Has thanked: 52 times
Been thanked: 77 times

Re: Lightly Glowing Generator Light--Normal?

#11

Post by john HD » Thu Jul 12, 2018 11:32 am

I have my '55 set up with a 2 brush and a 2 unit regulator, when I get the glowing light a quick cleaning of the contacts in the regulator usually solves the problem. I use a business card soaked in electrical cleaner with light pressure on the contact while scrubbing the card between the contacts.

I gave up on Accel regulators because I usually only got 6 months out of them, stock Delco units work the best.


john

Larry
Site sponsor
Site sponsor
Posts: 241
Joined: Wed Mar 01, 2006 10:14 pm
Bikes: -
Been thanked: 10 times

Re: Lightly Glowing Generator Light--Normal?

#12

Post by Larry » Thu Jul 12, 2018 1:17 pm

Sometimes the insulator behind the brush will warp, causing the brush to hang up.

cant-drive-55
Posts: 25
Joined: Sun Jul 30, 2017 4:02 am
Bikes: 59FLH, 76FXE
Location: chicago
Been thanked: 1 time

Re: Lightly Glowing Generator Light--Normal?

#13

Post by cant-drive-55 » Thu Jul 12, 2018 1:37 pm

The voltage relay will energize several times per second to maintain the set voltage. If the regulator is out of calibration, it may not be closing correctly, leaving the voltage difference.

Post Reply

Return to “Panhead”