I've just purchased a 30 year old gasoline engine forklift...
I note that the machine never seems to go off fast charge, by the machine's
A-meter. This is the old style voltage regulator style unit. I know nothing
about them. Are there any easy checks to know if the regulator is working
If it's a 6 or 12 volt battery and a "real" DC generator, not an
Put a good voltmeter directly across the battery while the engine is
running and you are seeing the ammeter showing a high charge rate.
If you read less than about 7.2 on a 6 volt system or 14.8 volts on a 12
volt one then the battery isn't yet fully charged and the high charging
current is just trying to charge it.
How olde is the battery? It may be a junker and never really reach it's
full charge voltage. You can test that by charging it for a good long
time with a line powered charger.
I don't recall any "easy" way to "prove" an old style voltage regulator
is OK and adjusted properly. Many of them had screwdriver adjustments
inside which changed the tension on springs. If someone who didn't know
his ass from his elbow got inside and F'd those adjustments up they'd
have to be reset. You'd need a high current variable voltage source, a
variable high current load resistor and decent voltmeters and ammeters
to be able to do a thorough "bench test" of one of those beasts.
Most of those old regulators had three relay like devices in them. One
was a "cutout" which opened the charge path to the battery when the
engine was stopped, so the battery didn't try and motor the generator,
burning something up. It could be replaced by a hefty solid state diode
nowadays and accomplish the same thing.
The second was a voltage operated relay with normally closed contacts
which opened the field supply to the genny when the output voltage got
high enough to mean the battery was fully charged.
The third was a current operated relay with normally closed contacts
which sensed the genny's output current and opened the field supply to
the genny if that current got higher than the sytstem's design limit.
I recall seeing some "Two relay" voltage regulators where the functions
of the voltage sensing and current sensing relays were combined into one
relay with two coils on it.
Thas' about all I recall about them.
If it's an alternator system with a separate voltage regulator ask a
"Karl Townsend" wrote in
message news:B1kIg.2168$ firstname.lastname@example.org...
This problem will be real easy for you to solve.
I suspect you have an alternator on the 1976 forklift.
Measure the battery's terminal voltage while the forklift is charging.
If the battery voltage is below 14, the system may be charging properly.
Note, it is easy to install a solid state regulator in place of the "old
style" (mechanical relay type regulator).
OK, at 3/4 throttle I'm up to 18.5 volts. Then the neg probe rattled off,
hit the fan, and got mangled :( Time for new parts?
I've not done this, just a replacement part to order?
On my tractor, when I fried an alternator due to this, I just replaced the
alternator with the GM style alternator with regulator included. Is this a
better route? Then, I have a new alternator also.
"Karl Townsend" wrote in
message news:OOlIg.2203$ email@example.com...
If you can mount a Delco alternator with internal regulator in place of
the one thats now on the forklift, do it.
It is likely that you could put a new voltage regulator on the one you
have on the forelift now, and that alternator will work.
For now, disconnect the field wire from that alternator.
This is a good time to get a new battery too. Any battery that allows
an alternator to get its terminal voltage up to 18.5 volts is too close to
If, for some reason you want to replace only the regulator, I can get one
for you (no$$).
I'll second the Delco alternator recommendation. I did the same thing on
a backhoe that originally had a 55A Motorola alternator with external
regulator. Just put an 85A or so Delco in it's place for about $20 from
the salvage yard.
I would stop using this machine until you solve the problem. A farm
friend stopped by one day and said "gee, my alternator belt is
screeching and I can't tighten it up enough to make it stop." I checked
that voltage at the battery and it was 16.5. I told him to go get it
fixed right away because at the minimum he would likely blow out bulbs,
etc. He didn't. A week later, while waiting at a red light, the whole
truck burned up.
Karl Townsend wrote:
Pretty much how I got my current truck . The owner finally got tired of
paying a shop to install new coils , alternators , regulators and
electronic ignition modules along with paying tow truck drives . The
truck was putting out 18 volts and toasting everything . I never did
find out exactly where the problem was as the wiring was a rats nest . I
rewired it and the problem went away . Maybe try mocking up a small loop
eliminating as many circuits as you can . If it tests OK add circuits
until the problem resurfaces . Luck
Hmm. But the hourmeter/tach on the diesel is fed from the back of the
generator (yep, generator, at least according to the manuals - whopping
22 amp unit), which has been disconnected along with ~98.2% of the
wiring on the tractor since before I got it. I could get a replacement
electro-mech VR, but I don't find the concept appeals much. On the other
hand, it would be nice to actually charge the battery in the tractor,
permitting me to use the correct size battery, as opposed to the
wal-mart car battery that had been retrofitted, and which comes home to
sit on the battery charger on a regular basis.
I didnt get the original message that included a reference to the problem
of running a tach from the signals available from a "generator". So, this
Top Post seems appropriate.
It is common for an Alternator to be referred to as being a Generator.
Alternators are referred to as AC Generators in Delco texts.
The half wave rectified stator voltage from a 3 phase Alternator (with a
diode trio) is often used to provide an AC voltage whose frequency directly
relates to engine RPM.
If you had an alternator with the same diameter pulley as was on the
original alternator, any alternator can be used for the tach signal
generator by connecting to its diode trio. That might involve installing a
diode trio on some alternators. But that isnt difficult.
"whopping 22 amp unit"
Most Utility vehicles, like forklifts dont include alot of electrical load
while running. They need mostly to only replace the charge lost during
start cranking. So, Low Current rated alternators are sufficient.
High current rated alternators commonly have Delta Connected Stators.
Low current rated alternators are Star Connected Stators. An alternator
with a Star Connected Stator will provide a given output at a lower RPM
than an alternator with a Delta Connected Stator.
Well, you did get "the original message...running a tach", as that was
something I brought up in the message you replied to, not something Karl
The tach/hourmeter in question is run by a mechanical drive, similar to
a speedo cable, so it works fine now when the only part of the
electrical system that works (or is even connected) is the starter
motor. Thus, if I replace the generator with the otherwise nice solution
Karl found, I lose the tach/hourmeter (not that the hourmeter means
much, as it's was disconnected for god knows how long at some prior
point in its life - but it does give me service interval info). Besides
which, at some point I made a basic investigation of my generator and it
does put out voltage - it just needs regulation. The old electromech
regulator is full of paint (bad spraypaint job done at some point, cover
missing, whole thing covered in yellow), and suspect even before that
problem. Old tractor parts places have the exact replacement, but I'm
frankly more comfortable with a solid state solution.
I am only guessing now, but it might be that your tractor has a DC
generator that includes a mechanical drive for the tach.
There are alot of types of DC generators, so there is no way to know which
type you have. If you knew the type of generator, it would be easy to get
a voltage+current regulator.
Have you considered leaving the DC generator in place to drive the tach
but disconnect its electrical, then add a small alternator?
I think some of the replacement regulators are actually solid state, but I
do not know which ones. The mechanical regulators are actually very reliable
and were used for many years on probably millions of vehicles. They can be
cleaned and adjusted. I think you would be perfectly happy with a correct