ammeter reading on 69FJ40 (1 Viewer)
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[quote author=theo link=board=1;threadid=8977;start=msg78057#msg78057 date=1071878383]
Moon refraction
[/quote]
Now there's something I can get a handle on.
Moon refraction
[/quote]
Now there's something I can get a handle on.
Alright Old Fart 
-
Only ammeter I've ever seen that didn't do this jumpin around is the ammeter on my 1950 Farmall, it has a generator with manual regulator (read switch that allows you to pick the amount of charge you want).
That sucker never moves!
I think the inherent likelihood of ammeters to swing around a lot is probably part of the reason new trucks have padded voltmeters, they are less likely have the same illusion of an improperly operating charging system than a normal ammeter. Voltmeters also only show potential difference, not flow, like an ammeter. There is naturally less of a flucuation when showing potential difference instead of flow, which naturally has more punctuated flucuations. If you really wanted to I bet you could pad your ammeter with a capacitor. I might have to dig out the old analog multimeter and see what it does with the blinkers on in both amp mode and volt mode.
-Only ammeter I've ever seen that didn't do this jumpin around is the ammeter on my 1950 Farmall, it has a generator with manual regulator (read switch that allows you to pick the amount of charge you want).
That sucker never moves!
I think the inherent likelihood of ammeters to swing around a lot is probably part of the reason new trucks have padded voltmeters, they are less likely have the same illusion of an improperly operating charging system than a normal ammeter. Voltmeters also only show potential difference, not flow, like an ammeter. There is naturally less of a flucuation when showing potential difference instead of flow, which naturally has more punctuated flucuations. If you really wanted to I bet you could pad your ammeter with a capacitor. I might have to dig out the old analog multimeter and see what it does with the blinkers on in both amp mode and volt mode.
I was hoping the old fart and moon refraction would put you fellas off long enough for me to collect my thoughts! Didn't work but I found these statements just now for what it's worth:
"Some oscillation occurs from regulator "hunt" as the regulator cycles in an attempt to control alternator current with field circuit voltage." http://www.piperowner.com/feature.htm
"> 2) Is there a better alternator? (that's a stupid question!!!...) What is a
> better alternator? One with a solid-state regulator built in. It will get rid of the ammeter fluctuation and will provide more consistent voltage because the solid-state regulator operates smoothly and continuously, unlike the stepped operation of an old-fashioned relay-type voltage regulator." http://realbig.com/detomaso/1997-04/9.html
I think the upshot is that mechanical regulators work by opening and closing points as needed. So the charge current is either all the way on or all the way off. And, it can only respond as fast as a set of points can open and close. Solid state regulators are able to cycle at electronic speed.
Cruisin, you should see the custom built snow plow I have. Has a Farmall Cub rear end and transmission with a chev tranny also. I'll get a photo. You'd like it you bein a country boy and all.
I have to go home now. My hair hurts.
"Some oscillation occurs from regulator "hunt" as the regulator cycles in an attempt to control alternator current with field circuit voltage." http://www.piperowner.com/feature.htm
"> 2) Is there a better alternator? (that's a stupid question!!!...) What is a
> better alternator? One with a solid-state regulator built in. It will get rid of the ammeter fluctuation and will provide more consistent voltage because the solid-state regulator operates smoothly and continuously, unlike the stepped operation of an old-fashioned relay-type voltage regulator." http://realbig.com/detomaso/1997-04/9.html
I think the upshot is that mechanical regulators work by opening and closing points as needed. So the charge current is either all the way on or all the way off. And, it can only respond as fast as a set of points can open and close. Solid state regulators are able to cycle at electronic speed.
Cruisin, you should see the custom built snow plow I have. Has a Farmall Cub rear end and transmission with a chev tranny also. I'll get a photo. You'd like it you bein a country boy and all.
I have to go home now. My hair hurts.
The resistance across a light bulb filament is very low at low temperatures, and rises extremely quickly as the temperature increases. Therefore, when a bulb lights up, initial current flow is very high until the temperature/resistance slows it to practically nil. As soon as the electrical flow is cut off, temperature drops (especially at low ambient conditions as found in winter outdoors), and the resistance falls once more across the filament, setting up for another current swing. Voltage, however, does not change.
How's that?
How's that?
Ton replaced his mechanical voltage reg with an electric solid state one, and I may do the same. That might lower the flucuations somewhat.
[quote author=theo link=board=1;threadid=8977;start=msg78070#msg78070 date=1071879789]Cruisin, you should see the custom built snow plow I have. Has a Farmall Cub rear end and transmission with a chev tranny also. I'll get a photo. You'd like it you bein a country boy and all.
[/quote]
I'd like to see it. Sounds..um...unique.
[/quote]
I'd like to see it. Sounds..um...unique.
[quote author=IDave link=board=1;threadid=8977;start=msg78074#msg78074 date=1071880169]
The resistance across a light bulb filament is very low at low temperatures, and rises extremely quickly as the temperature increases. Therefore, when a bulb lights up, initial current flow is very high until the temperature/resistance slows it to practically nil. As soon as the electrical flow is cut off, temperature drops (especially at low ambient conditions as found in winter outdoors), and the resistance falls once more across the filament, setting up for another current swing. Voltage, however, does not change.
How's that?
[/quote]
Draw one for Idaho!
Cruisin, a photo is forthcoming.
(I really am going home, just as soon as my wife shows up with some power steering fluid so I can limp my 302 back to the barn. Replaced that steering pump less than a year ago. And the water pump on my 40 is going out too. Both NAPA items and both pretty new. Starting to lose faith in NAPA.)
later
The resistance across a light bulb filament is very low at low temperatures, and rises extremely quickly as the temperature increases. Therefore, when a bulb lights up, initial current flow is very high until the temperature/resistance slows it to practically nil. As soon as the electrical flow is cut off, temperature drops (especially at low ambient conditions as found in winter outdoors), and the resistance falls once more across the filament, setting up for another current swing. Voltage, however, does not change.
How's that?
[/quote]
Draw one for Idaho!
Cruisin, a photo is forthcoming.
(I really am going home, just as soon as my wife shows up with some power steering fluid so I can limp my 302 back to the barn. Replaced that steering pump less than a year ago. And the water pump on my 40 is going out too. Both NAPA items and both pretty new. Starting to lose faith in NAPA.)
later
Hi guys, here are my two (euro) cents. Bailey, indeed I relaced my mechanical volt.reg. with a solid state type. But ... the ammeter still bounces with the turn signal, or whenever I switch on/off an electric device. These are only short spikes up to + or - 5 amps (approximately). I don't worry about that; it's normal behaviour. Such a spike is caused by an overreaction of the regulator circuit. When you switch on a cold lamp it will draw power from the battery and battery voltage will drop (a little). The regulator reacts immediately and makes the alternator charge more. That's the spike you see. When the lamp is turned off there is the same reaction but in the opposite direction.
The Toyota ammeter is quite sensitive; you see every spike. Other ammeters are dampened, and you don't see spikes, although they are there ...
I would not worry about spikes of up to + or - 10 amps. What matters is that the average reading of the ammeter is in the middle (0 amps) or just a little above (say 1 amp). Of course right after starting the engine, the ammeter should show a firm charge current (approx 20 amps) to recharge the battery. But under normal conditions that won't take more than 5 minutes.
My mechanical voltage regulator was broke and constantly charging the battery. Overcharging will harm the battery. If your mechanical regulator works fine (the ammeter is in the middle) ... just leave it.
Ton
The Toyota ammeter is quite sensitive; you see every spike. Other ammeters are dampened, and you don't see spikes, although they are there ...
I would not worry about spikes of up to + or - 10 amps. What matters is that the average reading of the ammeter is in the middle (0 amps) or just a little above (say 1 amp). Of course right after starting the engine, the ammeter should show a firm charge current (approx 20 amps) to recharge the battery. But under normal conditions that won't take more than 5 minutes.
My mechanical voltage regulator was broke and constantly charging the battery. Overcharging will harm the battery. If your mechanical regulator works fine (the ammeter is in the middle) ... just leave it.
Ton
This has becom way too academic! If this problem is not affecting performance than let it be. God knows there are plenty of other things on my cruiser to futz with
Bouncing of the needle is one thing, what about when your lights dim? Same situation or is it more indicative of battery/alternator issues?
Bouncing of the needle is one thing, what about when your lights dim? Same situation or is it more indicative of battery/alternator issues?
Dimming lights could be a grounding or alternator/alt. brushes issue.
To a degree I would just consider it normal, especially at low RPM's.
To a degree I would just consider it normal, especially at low RPM's.
Dan,
Are your lights dimming when you are sitting at idle at a stop sign, or light? Or are they dimming as you get sleepier while driving home after your measley 30 hour call shift?
Are your lights dimming when you are sitting at idle at a stop sign, or light? Or are they dimming as you get sleepier while driving home after your measley 30 hour call shift?
I was told by an electrician that dim lights and a severely bouncing meter needle is telling you something is wrong. He also said the wires to the meter and the connections could be the cause, since all the charge is passing thru it. Check the wires and connections for corrosion and make sure it's the proper gauge wire.
A severe bouncing meter (not the spikes caused by turn-signal or switching devices on/off) and dim lights could indicate corroded connections. Another probable cause are worn brushes in your alternator.
Ton
Ton
New brushes muted the bouncing for my ammeter to some extent.
Lights dim when I am at idle, rev and they birighten up. erember I am a newbie, so I got to ask....brushes? Are these easily and economically replaced? Need a pic or something (IDave, is there the equivalent of Netter for Autos?)
Go on, tell me the "when I was an intern" stories. Now our program directers are kicking us out the door at 30 hours so the ACGME doesn't yank the programs certification. Just a few months ago they make Yale's Medicine Program an example and shut them down. Scared a few DMEs.
Go on, tell me the "when I was an intern" stories. Now our program directers are kicking us out the door at 30 hours so the ACGME doesn't yank the programs certification. Just a few months ago they make Yale's Medicine Program an example and shut them down. Scared a few DMEs.
Took me about an hour and a half to replace the brushes on my stock F alternator, a year ago when i knew even less than I do now. I imagine it would be about the same for your truck (GM or Toyo alt.?)
Only "special" tool I needed was a soldering gun.
Once you get the sucker opened up its pretty self explanatory. Napa carries them between $5-15 IIRC.
Only "special" tool I needed was a soldering gun.
Once you get the sucker opened up its pretty self explanatory. Napa carries them between $5-15 IIRC.
What is happening to you Dan (I mean your car, actually) is NORMAL. The alternator puts out an anaemic amount of current to begin with. Then, the OEM headlight wiring is marginal for the job. If you have the original size lights (45 Watts at low, IIRC) they aren't too bright to begin with. (Kind of like certain Pace Academy Students). If you have replaced them with higher wattage bulbs, they are even more limited at idle. You can either live with the dimming (kind of a courtesy lighting at intersections), or turn up your idle speed a bit to compensate. Or, you can go to a heavier duty alternator, and you can upgrade the wiring harness, as far as the headlights go, to improve current flow. It is POSSIBLE that your brushes are getting worn and that's contributing to the dimming, but probably not. You can remove the alternator and the folks at NAPA will bench test it (probably for free). If it looks like it might be wearing out, then for about $7 you could buy new brushes. They are basically cubes of metal with wire pigtails that are held against the main alternator axle by springs. When they are new, things may even be temporarily worse, since their squared off surface has less contact than your old brushes, which have worn to shape, on the axle curve. As Bailey says, replacing the brushes is mainly a job of opening the housing with a screwdriver, detaching the pigtail with a soldering iron, and soldering on a new brush. (When I decided to do this, I found that the brushes were worn, but all I had to do was lengthen the pigtail and the spring pushed them further in and they had new life.) The toughest part is putting the alternator back together, because you have to push the brush into its spring and hold it there. The secret to that is the paper clip wire sized hole in the housing that you use to stick a wire through to hold the brush back.
Speaking of Netter, you would be very happy owning a set of OEM Manuals (Engine Manual and Chassis and Body Manual) for your rig. Makes life so much easier!
Speaking of Netter, you would be very happy owning a set of OEM Manuals (Engine Manual and Chassis and Body Manual) for your rig. Makes life so much easier!
[quote author=IDave link=board=1;threadid=8977;start=msg78569#msg78569 date=1071984246]
(Kind of like certain Pace Academy Students)[/quote]
Uh Whats that supposed to mean Dave? ???
(Kind of like certain Pace Academy Students)[/quote]
Uh Whats that supposed to mean Dave? ???
Looking over these posts I am getting real comfortable with the bounce in my 40's ammeter. I have wondered about this bounce for a long time but thanks to the magic of the internet you guys have put my mind at rest. This issue inspired an amazing number of pixels!
