Generator lamp "sometimes" comes to live...

[Anders]

Is there anyone who knows what might be my problem regarding the generator lamp. If I just go out driving, and do it for an hour or so, there is no problem. But as soon as I have been in slow traffic or in a queue, and the temp goes up a bit, the lamp lids up. If I then accelerate again, it goes away but as soon as I let the trottle off, it turns on again. The generator is overhauled with new brushes and I have a new relay.

[Guest]

Are you running electric cooling fans?
What else electrical is on?
I had a similar problem when I had my fans on all the time, once I put a relay it fixed the problem but I do get a faint glow when they kick in.
I'd check the battery voltage with a meter when it happens

Richard

[Anders]

No, i don't have a electric fan, or other electric things goong on, as far as i know, except lights.

[Guest]

Believe it or not the owners manual says that's normal when you stop at a light. I know i don't like it. going to go alt. one day

[del]

Is there anyone who knows what might be my problem regarding the generator lamp. If I just go out driving, and do it for an hour or so, there is no problem. But as soon as I have been in slow traffic or in a queue, and the temp goes up a bit, the lamp lids up. If I then accelerate again, it goes away but as soon as I let the trottle off, it turns on again. The generator is overhauled with new brushes and I have a new relay.

Hi Anders - My '60 does the same thing at times. I notice that is seems to be more frequent just after I come to a sudden stop - - like if a traffic light unexpectedly turns red. Also seems to happen more when she has been running for a while. I'll often shift into Neutral at a stop light and the higher RPMs make the flicker go away. Otherwise, I just try to ignore it.

[Anders]

Great support guys! Iīm less nervous from now on!

[Guest]

Believe it or not the owners manual says that's normal when you stop at a light. I know i don't like it. going to go alt. one day

Where is the LIKE button! I changed mine to a Alternator and that light coming on like that stopped!
Richard D. Hord

[Guest]

That'll stop when i get done the other 3 cars I'm on. I'm getin ready to ask Mr obama for a loan lol.................

[simplyconnected]

Here's the deal: Your GEN light is powered on BOTH ends and the dash bulb socket IS NOT grounded.

So... What does the light really do and what does it indicate?

The lamp is fed from the key switch and it goes to the Armature post of your Regulator. The light bulb current 'tickles' the generator armature and makes sure the generator starts producing Neg Gnd, before the engine moves.

That light compares battery voltage (from the key sw) to the generator output voltage. If the battery has more voltage than the generator output, the light shines.

Here are some reasons for the light to shine:
· The key is on but the engine isn't moving (yet).
· You threw a belt.
· The battery is completely charged, but the Generator is moving slow and producing less voltage than the battery has.

Do not get stuck with a burned out GEN light bulb or your Generator may not charge. That light is very important. I love to see it 'on' when I turn the key, then go off when the engine starts. - Dave

[kuusamon]

I know for sure that it is a typical generator behavior for the reasons Dave stated. Alternators usually do not have this behavior because they are working different. If this happens with an alternator then you have problem of a shot diode or something.

[Anders]

Here are some reasons for the light to shine:
· The key is on but the engine isn't moving (yet).
· You threw a belt.
· The battery is completely charged, but the Generator is moving slow and producing less voltage than the battery has.
- Dave

So my reason must be #3 then. Are you sugesting my belt is slipping? It did before, but that I could hear very clear, and the behave from the red light was different. It was "following" the engine revs and became stronger as I pressed the trottle and stopped when I went into idle. What I am talking about here is something opposite that sometimes suddenly appears when the engine seems to be very hot. The light turns red like I switched it is "on" when I go off trottle and disapear when I push the pedal down. Iīm confused again. Any sugestion about what I shall do?

[tbird430]

Can you turn the idle screw up, maybe 100rpm's?

[simplyconnected]

Ronald Kuusamo, we use the same GEN light for three-wire alternators but you are correct, they do act differently.

My last alternator (a 75-amp) went bad. The GEN light came on. It was at night when my headlights were on. Then I noticed, when I gave a little gas, the headlights went very bright. Stopped at a light, they went to normal. Seeing the GEN light scares me, but in this case the headlights told me the internal regulator was putting out as much as possible all the time. I changed to a 160-amp alternator I bought from Ray Clark, now everything works just fine.

Anders, the rules still apply to all generators. If you have a loose belt the screaming noise will drive you nuts, but it is also evidence that the Generator is trying to output more electrical watts than the belt can deliver in mechanical HP. (~746-watts = one HP.)

With the key on, all Generators use field power regardless of engine speed. Stopped at a light, the engine runs slow and the battery is draining. Then the GEN light comes on because the battery voltage is still higher than the generator's output voltage. As soon as you give a little gas (which runs the Generator faster) the light goes out when battery voltage equals Generator output voltage.

One way to stop the squealing is by installing a slightly larger pulley, which gives a 'longer lever' to the Generator. The trade-off is, your engine will need to run a little faster.

The obvious fix is to tighten your belts and stop them from slipping. If this doesn't help, buy a new belt. New rubber is softer and sticky (like new tires). Old rubber gets hard and cracks.

Belts slip, and so do tires. When slippage gets excessive they both squeal. I hope I explained myself well. If you have questions, let me know. - Dave

[Anders]

I think... ( not 100% sure though...) I follow, but I feel stupid as I donīt understand the difference between a generator and a alternator....
Before the summer, I have my generator checked and overhauled with new brushes at a shop, where a old guy, who have done this for decades ( one of the few left...) tuned it together with my Generator Voltage Regulator, but he said the regulator was on the edge of itīs life and proposed me to buy a new, so I did that. Even if I have tighten up my belt, and yes, they are all brand new since this summer, perhaps it slips without me notice it? I didnīt have this "problem" or issues before I took out the engine and started fixing other small issues. Whatīs makes me even more confused is that since I did all this, I have not been forced to charge my battery once, as the car starts up every time easy even if I didnīt drive it for weeks. Last year, and before that, I needed to charge the battery pretty much every 2:nd or 3:rd time I wanted to drive.
Hmmmm.....

[simplyconnected]

Anders, think about this... your front wheels turn fewer times than your drive wheels. They don't always squeal. The same thing happens with your generator belt & pulley. If there is a load, there is always losses in the form of slippage.

At Ford, we had problems with aluminum wheels spinning inside the tires on the 'Roadability' (or Scuff machines). This happens on the assembly line while the tire bead is still wet from 'mounting'. When it happens, the tires imbalance.

Generators never have internal regulators. The only parts that 'wear' are, brushes, commutator segments, and bearings. These brushes must be large enough to carry ALL charging current. External Regulators have resistors that get very hot and brittle, and usually fail over time.

Alternators usually have internal regulators. There are smaller brushes that ride on Slip Rings (no commutator segments) because the rotating shaft carries the FIELD current. These brushes tend to last well over 100k-miles because they don't arc or carry much current. This is a much more efficient design because the Alternator starts charging at a much lower speed. Alternators are really, three phase AC generators. We use huge internal diodes to rectify each phase from AC to DC.

A properly maintained quality battery should last four to five years. - Dave