Belt Driven Generator Frequently
- Can I operate the AB25, AB50, AB60,
AR100 and AR250 in both clockwise or counter clockwise directions when
facing the extended shaft?
Yes. All models can be
operated either clockwise or counter clockwise.
- What are the shaft diameters?
The models AB25, AB50 and
AB60 have an outside diameter of .875 inches (7/8") with a .1875
(3/16") keyway. The key is included.
Model AR100 has an outside diameter of 1.0 inch with a .25 inch (1/4")
keyway. The key is included. The AR250 has an outside
diameter of 35MM (1.377") with a 10MM (13/32") keyway. The key is
- What size pulley do I need to operate
See the web page Determining
Pulley Diameter. Please note that models AB25, AB50 and AB60
require a single pulley with preferably a "B" size belt. Model
AR100 MUST us a two groove "B" pulley and AR250 requires a three groove
- Where can I buy a pulley?
Local automotive supply
companies, industrial supply companies, W.W. Granger, King Bearing,
Motion Industries, etc.
- What size engine do I need to operate
AB25 requires 5 H.P.
AB50 requires 8 H.P.
AB60 requires 11 H.P.
AR100 requires 16 to 18 H.P.
AR250 requires 50 H.P.
Practically all one and two
cylinder engines (Briggs and Stratton, Vanguard, Honda, Kohler, Onan,
Robin, Kawasaki, Kubota, Tecumseh, etc.) have rated horse power only
when operating at 3600 R.P.M. If you operate these types of
engines below 3600 R.P.M., you will reduce the horse power of these
engines. Also, if you use a garden tractor engine they are
usually governed down in speed and possibly only 2/3 of the rated horse
power will be available. If automobile engines are used, even
though the rated horse power is substantially above 18 horse power, if
the engine is only idling, you may not have enough horse power.
Engines have power curves and idling speed allows very small amounts of
available horse power. You must operate automobile engines at
enough speed to have sufficient horse power. All engines MUST
have a mechanical governor to fix the speed of the engine.
- What will happen if I do not have
enough horse power to run the generator?
All of the above generators
require the horse power listed to obtain the rated electrical
output. If you do not have enough horse power, you will not get
the full power out of the generator. If you try to get the rated
output (wattage) and do not have enough horse power, you will get low
voltage and higher amperage which can cause damage to the items you are
operating and cause damage to the generator.
- If I do not have enough horse power,
won't the circuit breakers trip and protect the circuit by preventing
high amperage form damaging the items that the generator is operating?
All of the circuit breakers
ar thermal types which can hold up to 25% overload. These circuit
breakers can take a while to heat up before tripping to protect a
circuit. During the time the circuit breakers is heating up, the
high amperage is potentially causing damage to the items the generator
is operating. If there is a dead short circuit, the circuit
breakers will immediately trip.
- Instead of using pulleys, can I
directly couple the generator to an engine?
Yes. In order to
directly couple these generators to an extended shaft engine, you must
use couplings with spider gears. These types of couplings are
available from companies such as Lovejoy or Boston Gear and are
available at most industrial supply companies such as WW Grainger
etc. One coupling must fit the diameter of the generator shaft
and one coupling must fit the diameter of the engine shaft. The
spider insert fits between the two couplings to compensate for
- If I do not need a lot of power from
the generator, can I operate the generator at slow speeds?
No! All models of two
bearing generators MUST operate at 3600 R.P.M. If the generator
speed os less than 3600 R.P.M., the voltage and frequency (hertz) will
be lower than required and if the generator operates above 3600 R.P.M.,
the voltage and frequency (hertz) will be higher than required.
Either condition will cause damage to the items being operated by the
generator and also to the generator. Generator shaft speed below
3400 R.P.M. and above 3800 R.P.M. will cause damage to items and the
- How do I know what speed the engine and
generator are running?
All Voltmaster generators
have a voltmeter (except model AB25-PW). It is recommended that
you use a tachometer to determine the shaft speed of the
generator (3600 R.P.M.). If a tachometer is not available, when
the voltmeter reads at least 240 volts (except AB25 which reads 120
volts to a maximum of 130 volts) to a maximum of approximately 250
volts, you have reached 3600 R.P.M. on the generator shaft. For
model AB25-PW you need to plug in a voltmeter into the 120 volt
receptacle and upon reaching 125 to 130 volts, you are at the proper
generator shaft speed.
- I have a tractor. Can I run these
generators off the power take off (PTO)?
No. The PTO's on
tractors operate at either 540 R.P.M. on small horse power tractors
(usually below 40 horse power) or 1000 R.P.M. on larger tractors.
All of these generators MUST operate at 3600 R.P.M. and a direct
coupling to the tractors will cause low voltage. We do offer
tractor driven PTO generators.
- I have a garden tractor and want to
operate the generator in the vertical mode. Can this be
No. All of these
generators are designed to operate in the horizontal mode. The
generators will operate vertically, however they all have ball bearings
and vertical operation should require tapered roller bearings.
There is NO warranty for operation in the vertical mode.
- I just received my generator and I can
not get any electrical output from the unit. What is wrong?
Assuming the shaft of the
generator rotates freely, the most common problem is lack of enough
speed being transmitted from the engine to the generator. All of
these generators do not start producing electricity until they reach a
minimum speed of at least 2200 to 2400 R.P.M. Even at those low
speeds, the voltage on the generator is only operating at about
50%. Correct operating voltages of 120 and 240 volts will NOT
occur until the generator shaft runs at 3600 R.P.M..
- Can I use a hydraulic motor to run a
Yes as long as you adjust
the speed of the hydraulic motor to rotate the generator shaft at 3600
- What is the warranty on these units?
There is a one year limited
parts and labor warranty on all two bearing generators.
- The owners manual indicates a belt
guard must be installed. Why wasn't one provided with the
The generator manufacturer
has no idea of what size engine, pulleys or coupling will be used and
therefore a belt guard was not provided.
- Why wasn't a pulley provided with the
The generator manufacturer
has no idea of what size or type of engine the end user of the
- Can I run a computer, sound system or
other electronic equipment on these generators?
Models AB25, AB50, AB60,
AR100 and AR250 all feature voltage regulation +-5% and distortion of
6% or less. The end user's engine and governor determines the
ultimate output of the generator. If the engine governor is +-5%,
it is safe to operate electronic equipment. It is always strongly
recommended to use a U.P.S. (battery) system on all
computers. If the generator is operating electronic
equipment and electronic motors ( sump pumps, refrigerators, fans,
pumps, garage doors, compressors, etc.) these devices require the
engine governor to increase or decrease significantly and the engine
speed will change the electrical output and increase or decrease
voltage and frequency. Caution must be used when operating
electronic equipment and electric motors at the same time.
The rotor, stator, and other electrical components are covered
a 1 year limited warranty against defects in material and workmanship
date of purchase. The 1 year limited warranty on the engine is
separately by the engine manufacturer.
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