Subject: RE: Voltage Regulator
Author: murp-@aol.com
Date: May 18, 2001, 5:09 PM
Post ID: 1706781553
Keith,
Poor connections in this circuit will not cause the Gen warning light
to come on. That said, you really should make sure that all the
connections are clean and solid, especially the ones to ground.
What causes the warning light to come on is the voltage difference
between the battery voltage and the reference voltage output from the
generator. When the battery voltage is significantly higher (greater
than a few volts) than the reference voltage generator output, the bulb
will light.
Here is Murphy's troubleshooting guide for this circuit:
1. Load test the battery. A quick test would be to turn on the ignition
and the lights, and see if the battery voltage drops less than about 10
V in a minute or so. A bad battery is not likely to be the problem
because this voltage must be higher than the ref. voltage for the
warning light to come on.
2. With the engine running, check that the battery voltage goes up to
about 14 V when you rev the engine. If this is OK, it means that the
generator is in fact charging the battery, whether the warning light is
on or off. If the voltage goes much above this value (say 15V and
higher), then you may have a problem with your regulator. This would
also make your warning light stay on.
3. Check the battery voltage with respect to the reference voltage
output. Put the positive lead of your voltmeter on the pos. battery
terminal, and the negative lead on the D+ terminal of the regulator (the
voltage output of the generator is connected to this terminal on the
regulator with a grey/red wire according to my schematic). With ignition
on but engine off, you should see 12 V between these points (this is the
voltage difference which is lighting the warning light). With the engine
on, you should see this voltage decrease as you rev up the engine, until
there is no difference (which causes the light to go out). If the
voltage difference does not reduce below a volt or two, then there is
something wrong with this generator output. However, as long as the
battery is charging, you might not care.
Hope this helps,
Brian
'74 Eldo
'78 T3
Keith Ruff wrote:
| Was wondering how I can check to make sure the regulator is working OK. As part of my checks of the Gen Warning light issue posted earlier this week, someone mentioned checking the reference voltage at the regulator. I will be doing that this weekend, but figured I would check out the regulator also to make sure she is working properly. I did notice at 1st glance that the connectors on the regulator look pretty rusty, so I will clean them up and reconnect all of the wires, perhaps this is the cause of the gen warning light not going off but staying on in a Dim mode? Keith Ruff 71 Police Amabassador - NJ |