c. Low Speed Test. Immediately following the heat
alternating current generator to the 24-volt battery. The
load on the generator is varied by means of the load
run test as described in b above, operate the generator at
bank, the load bank being connected into the circuit by
1,000 rpm. Minimum output must be 50 amperes at 28
closing the 150 ampere load switch.
volts of direct current.
d. Insulting Test. Using a 500 volt, 60 cycle,
alternating current test lamp, apply 500 volt alternating
When a malfunction of the selenium
current across the fan of the generator and each
rectifier occurs, thoroughly ventilate
receptacle pin in turn for not less than one minute. No
circuit should be indicated; the lamp should not light,
the area to prevent inhalation of
poisonous fumes. Do not handle the
damaged selenium rectifier. Selen-
Care should be exercised in the use
ium oxide may be absorbed through
of test lamp circuits of 110 volts or
the skin, especially when the
higher. Injury or possible death by
electrocution can result from contact
observe this warning can result in
with the test lamp circuit and/or the
severe illness or death.
circuit under test.
b. Heat Run Tests. Perform the heat run test at
e. Overspeed Test. Disconnect the generator from
room temperature of 80° F. Operate the generator for
the electrical circuit and operate it at 3,000 rpm for 5
one hour at a minimum speed of 2,000 rpm under full
minutes. Lien for any unusual noises or heating that
load of 100 amperes, then reduce generator speed to
might indicate mechanical failure.
1,650 rpm. The generator should produce direct current
voltage of 28 volts with an output of 50 amperes and a
field current of 7.9 to 12 amperes.
Figure 50. Generator, metallic rectifier, and engine generator voltage
regulator test block wiring diagram.
Section II. GENERATOR VOLTAGE REGULATOR ASSEMBLY
regulator is an integral part of the cover for the watertight
box which contains the load relay and a voltage adjust
The generator voltage regulator consists of a carbon
pile voltage regulator and a load relay. The voltage