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View Full Version : Re: Alternator (Ammeter) Problem (Piper)


February 4th 19, 11:06 AM
On Sunday, August 27, 2000 at 11:05:49 AM UTC+10, Rick Potts wrote:
> I replaced the alternator in my Warrior (PA 28-151) this week and the
> prior problem (the alternator dropping offline periodically, up until
> the time it dropped offline and refused to come back on 200 miles from
> home) has been replaced by a new problem.
>
> The good news is the new alternator came online when I started the
> Warrior's engine this morning and, according to the ammeter, started
> producing electricity.
>
> The bad news is the ammeter needle then started to wiggle back and
> forth across the dial like a windshield wiper, from "0" on the left to
> about "30" on the right, about two times per second. Varying the
> engine speed didn't make a difference in how it behaved.
>
> I measured the battery voltage (at the cigarette outlet) and it
> remained steady at 14 to 15 volts. It didn't fluctuate at all, even
> though the ammeter needle was dancing all around.
>
> The Piper Service Manual's troubleshooting chart says that "excessive
> ammeter fluctuation" can be caused by a defective voltage regulator or
> excessive resistance in the field circuit. I hesitate to blame the
> voltage regulator when the voltage stays so steady, so is "excessive
> resistance" the likely culprit?
>
> For "excessive resistance" the manual recommends: "Check all
> connections and wire terminals in field circuit for deterioration such
> as loose binding posts, broken wire strands at terminals, etc..
> Tighten all connections and replace faulty terminals."
>
> I'm no expert at reading electrical diagrams, but it appears the
> "field circuit" would include the voltage regulator, the overvoltage
> relay and the alternator switch. The output side would include the
> ammeter and a large (6 gauge?) wire that runs to the battery
> contactor.
>
> The voltage regulator and the overvoltage relay are mounted up under
> the instrument panel, so getting to them won't be easy. The alternator
> switch, on the other hand, is quite easy to get to so I think I'll
> start there.
>
> Question: How is the split master switch mounted? Does the plastic
> cover piece come off the instrument panel with the switch mounting
> from the front? Or do I have to remove it from the rear somehow? I'd
> like to get in there to clean and tighten whatever connections are
> there.
>
> Or is the voltage regulator still a potential culprit?
>
> Thanks for any ideas!
>
>
>
>
>
> ------------------------------------
> Rick Potts Phoenix, Arizona
> N32334 PA 28-151 Warrior
> ------------------------------------

Hi,
I have encountered a problem with my PA28 Archer II where the Alt Light comes on and off and showing that it is charging between 13 to 14.8 volts, I have replaced the voltage regulator with a brand new unit it is still doing the same thing, also I tried a test where you by pass the over voltage regulator still the same signs, I have also changed the alternator with a serviceable unit and it also had the same symptoms, any one out there ever had this issue?
any insight would be appreciated

Cheers
Bill Q

February 8th 19, 05:40 AM
On Monday, February 4, 2019 at 3:06:58 AM UTC-8, wrote:
> On Sunday, August 27, 2000 at 11:05:49 AM UTC+10, Rick Potts wrote:
> > I replaced the alternator in my Warrior (PA 28-151) this week and the
> > prior problem (the alternator dropping offline periodically, up until
> > the time it dropped offline and refused to come back on 200 miles from
> > home) has been replaced by a new problem.
> >
> > The good news is the new alternator came online when I started the
> > Warrior's engine this morning and, according to the ammeter, started
> > producing electricity.
> >
> > The bad news is the ammeter needle then started to wiggle back and
> > forth across the dial like a windshield wiper, from "0" on the left to
> > about "30" on the right, about two times per second. Varying the
> > engine speed didn't make a difference in how it behaved.
> >
> > I measured the battery voltage (at the cigarette outlet) and it
> > remained steady at 14 to 15 volts. It didn't fluctuate at all, even
> > though the ammeter needle was dancing all around.
> >
> > The Piper Service Manual's troubleshooting chart says that "excessive
> > ammeter fluctuation" can be caused by a defective voltage regulator or
> > excessive resistance in the field circuit. I hesitate to blame the
> > voltage regulator when the voltage stays so steady, so is "excessive
> > resistance" the likely culprit?
> >
> > For "excessive resistance" the manual recommends: "Check all
> > connections and wire terminals in field circuit for deterioration such
> > as loose binding posts, broken wire strands at terminals, etc..
> > Tighten all connections and replace faulty terminals."
> >
> > I'm no expert at reading electrical diagrams, but it appears the
> > "field circuit" would include the voltage regulator, the overvoltage
> > relay and the alternator switch. The output side would include the
> > ammeter and a large (6 gauge?) wire that runs to the battery
> > contactor.
> >
> > The voltage regulator and the overvoltage relay are mounted up under
> > the instrument panel, so getting to them won't be easy. The alternator
> > switch, on the other hand, is quite easy to get to so I think I'll
> > start there.
> >
> > Question: How is the split master switch mounted? Does the plastic
> > cover piece come off the instrument panel with the switch mounting
> > from the front? Or do I have to remove it from the rear somehow? I'd
> > like to get in there to clean and tighten whatever connections are
> > there.
> >
> > Or is the voltage regulator still a potential culprit?
> >
> > Thanks for any ideas!
> >
> >
> >
> >
> >
> > ------------------------------------
> > Rick Potts Phoenix, Arizona
> > N32334 PA 28-151 Warrior
> > ------------------------------------
>
> Hi,
> I have encountered a problem with my PA28 Archer II where the Alt Light comes on and off and showing that it is charging between 13 to 14.8 volts, I have replaced the voltage regulator with a brand new unit it is still doing the same thing, also I tried a test where you by pass the over voltage regulator still the same signs, I have also changed the alternator with a serviceable unit and it also had the same symptoms, any one out there ever had this issue?
> any insight would be appreciated
>
> Cheers
> Bill Q

I'm having the exact same problem with my Tomahawk PA-38-112. Replaced the battery, voltage regulator, cleaned all the ground connections, no go..My alternator voltage is reading high (15.5 volts) with a pulsing ammeter..looking for help also..


Thanks Greg

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