Zena 150 series, Manual

Page: 6 / 12

2
typically an indication that grease, or some similar material may have caused “fouling” or
glazing of the brushes and/or internal slip-rings. Cleaning can be accomplished in the field,
if necessary
5
, but is best done under factory (dust free) conditions.
Disconnect the generator’s output terminal from any load, and check in the electrical
resistance between
each of the terminals and the case of the Power Generator.
A normal reading is an “open” circuit (an infinite resistance).
If your meter shows
any measurable resistance, from either terminal to the case, your
Power Generator has a possible defect in its output power insulation system, and the
generator should be returned to the factory for repair
6 .
If the foregoing resistance readings are correct, a test of the output voltage of the generator
under full field / full speed operating conditions should be made.
If you are using the generator in a welding application, this is done by starting the welder
(pressing the power button or other on/off control in use) and rotating the power control to
maximum (fully CW).
If you are using the generator in a charging/generating application, this is done by
temporarily (and briefly) connecting one of the two control terminals to ground, and the
other to a source of DC voltage between 12 to 14.5VDC while the generator is being rotated
at a speed of between 6,000 to 7,000 rpm -- with both of the generator’s output terminals
disconnected from any loads (particularly a battery) 7
.
A normal DC voltage reading between the positive and negative terminals of the generator,
under these conditions, is between 70-80 volts. A reading substantially lower than this (say,
50-55 volts), indicates a possible failure in the generator’s rectifier or stator assemblies, and
the generator should be returned to the factory for repair
8
.
5
See enclosed instructions.
6
This sort of problem can be repaired in the field, by removing a foreign object, or moving a component which is
touching the case interior, or replacing one of two sub assemblies. Additional trouble analysis, and some
disassembly, may be required to determine which component to replace.
7
Use insulated 1/4” spade terminals or insulated clip leads for your connections to prevent an inadvertent short
circuit during testing.
8
If desired, this component is field replaceable by a competent technician (or skilled owner).