Is alternator warning light necessary ??
Ian Hastie
warning light wired in to the alternators charging circuit. I have
recently been told that it is impossible for the alternator to be
charging at full capacity without a warning light, does anybody know if
this is correct?
--
Ian Hastie
Ethelred The Unready
the bulb, providing a small current which produces enough magnetism to start
the alternator charging. Without the bulb, a failsafe in the regulator
provides this current, but not as great a current as with it.
Ethel
>it is impossible for the alternator to be
>charging at full capacity without a warning light, does anybody know >if
this is correct?
>Ian Hastie
Eamonn McGonigle
alternator warning light activates the fixed "electromagnets" in the
alternator (replacing the ordinary magnets you would find in a dynamo). No
current passing through these coils => no magnetic field inside the
alternator => no output from the alternator. Once the alternator starts
spinning, the voltage to power the fixed electromagnets is supplied from the
output of the alternator (via the control unit, which varies the current
through these coils to control the alternator's output). This rise in
voltage at the input to the coils is what causes the alternator warning
light to go out (since there now little or no voltage difference between the
12 volts supplied by the battery to the light and the voltage supplied from
the alternator's control unit to the input of the magnets (= negative side
of warning light).
Eamonn
Ian Hastie wrote in message ...
>My car, a Striker kit car, fitted with a 1600 Ford CVH has never had a
>warning light wired in to the alternators charging circuit. I have
>recently been told that it is impossible for the alternator to be
>charging at full capacity without a warning light, does anybody know if
>this is correct?
>--
>Ian Hastie
spark
it needs the warning light to provide the "ex" to actually kick it in at
first,after this it is effectively self sufficient.You tend to find that if
it has charged recently there is enough residual magnetism left in the rotor
to get it to charge,once it has started to charge the lack of a warning
light will not stop it from reaching its full charging capacity.
Spark
Andrew Willoughby
>
> My car, a Striker kit car, fitted with a 1600 Ford CVH has never had a
> warning light wired in to the alternators charging circuit. I have
> recently been told that it is impossible for the alternator to be
> charging at full capacity without a warning light, does anybody know if
> this is correct?
As other have said, most alternators do need the warning light.
Are you sure you haven't got a light hidden somewhere? I have
seen a car that had a bulb taped inside the wiring near the
alternator. No, I don't know why.
--
Andrew
Relax, enjoy life!
Andy Dingley
>recently been told that it is impossible for the alternator to be
>charging at full capacity without a warning light,
Depends on the alternator. Lucas ACR won't do a damned thing without
one, something with a decent regulator won't care. Some cars (e.g.
Renaults) never had warning lights in the first place. Personally I'd
fit one, just to tell me about belt failures before the temperature
starts to rise. If you're worried about electrical health, then a
voltmeter is a better idea. A tri-colour LED is only the same size as
a warning light anyway.
BTW - The bulb rating is crucial too.
--
Smert' Spamionam
Andrew W. MacFadyen
of a brocken fan belt. --- no fan belt = no water pump = blown engine
Andy M
Ian Hastie
<din...@codesmiths.com> writes
>Depends on the alternator. Lucas ACR won't do a damned thing without
>one, something with a decent regulator won't care. Some cars (e.g.
>Renaults) never had warning lights in the first place. Personally I'd
>fit one, just to tell me about belt failures before the temperature
>starts to rise. If you're worried about electrical health, then a
>voltmeter is a better idea. A tri-colour LED is only the same size as
>a warning light anyway.
>
>BTW - The bulb rating is crucial too.
I believe the alternator is a Motorola, How would I go about finding a
rating for the bulb.
Cheers.
--
Ian Hastie
Ian Hastie
<emc...@iol.ie> writes
>Possibly. In many configurations, the current passing through the
>alternator warning light activates the fixed "electromagnets" in the
>alternator (replacing the ordinary magnets you would find in a dynamo). No
>current passing through these coils => no magnetic field inside the
>alternator => no output from the alternator. Once the alternator starts
>spinning, the voltage to power the fixed electromagnets is supplied from the
>output of the alternator (via the control unit, which varies the current
>through these coils to control the alternator's output). This rise in
>voltage at the input to the coils is what causes the alternator warning
>light to go out (since there now little or no voltage difference between the
>12 volts supplied by the battery to the light and the voltage supplied from
>the alternator's control unit to the input of the magnets (= negative side
>of warning light).
So can I just take a feed from what would be the warning light terminal
on the alternator, run it through a 12v bulb to earth ?
Thanks for your help.
--
Ian Hastie
Ian Hastie
<saty...@hotmail.co.uk> writes
The car sits for long periods of time without being used so I'm sure any
residual magnetism would be lost. The battery has never held a good
charge though it never goes completely flat.
--
Ian Hastie
Ian Hastie
<And...@willouby.demon.co.uk> writes
>As other have said, most alternators do need the warning light.
>Are you sure you haven't got a light hidden somewhere? I have
>seen a car that had a bulb taped inside the wiring near the
>alternator. No, I don't know why.
No there is definitely no light, there is no wire taken off from the
terminal on the alternator.
--
Ian Hastie
Ian Hastie
<am...@post.almac.co.uk> writes
>Yes I am surprised it is charging at all ! -- also it serves as a warning
>of a brocken fan belt. --- no fan belt = no water pump = blown engine
>Andy M
>
On a CVH the water pump runs from the cam belt so that is not a problem
but I'm sure the alternators not charging properly. How do I go about
wiring a warning light into the system.
--
Ian Hastie
Andrew Willoughby
<i...@crusty.demon.co.uk> writes:
> So can I just take a feed from what would be the warning light terminal
> on the alternator, run it through a 12v bulb to earth ?
NO! Not through the bulb to *earth*.
From the alternator terminal through a small 12 volt bulb, to
anything which comes *live* with the ignition on.
Ian Sumner
Vibration or heat could remove residual magnetism. Time on its own will
not.
Ian
Ian Hastie
<g...@bofus.demon.co.uk> writes
>provide a valid indication of charge.
>
>This assumes you are using some ford dash, Vauxhall are similar.
>
>VW used an LED with a high rated resistor in the MkII Golf
Thanks for your help Gavin.
For various reasons it would be more convenient to use a 12v 3w bulb,
would this be OK or would it cause problems?
--
Ian Hastie
Roger
essential part of the alternator circuit and the alternator won't start
charging without it (the bulb passes a small current through the field
coils).