(3) The magnetic amplifier, operating at
1,000 cps, has 4 control windings and an
(3) Test the transformer for grounds by
output or power winding. Its purpose is to
testing between one lead of each winding
mix or totalize the control error signals
and amplify the result for use by the servo
actuator. The control windings include
by testing between one lead of the
secondary winding and one lead of the
back winding, load sharing winding, and
bias winding. The level of these DC
control windings affects the output of the
power winding which is the input to the
e. Inspection and Repair.
(1) Inspect the resistor for damaged ter-
b. Removal. Refer to figure 132 to remove the electric
minals, defective insulation and other
(2) Inspect the transformer for cracks, breaks,
90. Load Measurement Unit
broken terminals and evidence of
a. The load measurement unit, consisting of a
(a) A defective load measurement unit should
resistor, measures the total load on the generator set
regardless of power factor or phase. The DC output of
91. Electro-Hydraulic Actuator
this unit is connected to the feedback and paralleling cir-
cuits of the LEH control unit.
. Figure 1 and 128 show the connection
load measurement unit to other components.
the electric control unit and converts
remove and install the load measurement unit.
these signals to an actuator motion that -
positions the engine throttle properly. The
actuator is composed of a control valve, a
piston, and a linkage assembly.
(2) The electro-hydraulic control valve
receives its control signals from the
magamp output in the electrical control
unit. The control valve converts the
proportional push pull electrical input to a
proportional push pull hydraulic output.
The control valve requires a constant hy-
draulic input of 2 gallons/minute at 300
(3) The push pull hydraulic output of the control
valve operates a piston. Whenever the push
Figure 133. Load measurement unit.
pull hydraulic signal is unbalanced, the piston
will move in a direction depending upon
(1) Test the load resistor using an ohmmeter.