Power Module Panel Assembly - Hobart 60CU20 Operation And Maintenance Manual With Illustrated Parts List

OM-2226 / Operation and Maintenance Manual
60CU20 / Series 500062 / 400 Hz. Generator Set

9) Power Module Panel Assembly

The power module panel assembly sometimes referred to as the contactor panel, is located at the rear of
the machine under the control box. The panel assembly provides a means of connecting and
disconnecting generator output to and from the aircraft.
a) Load contactor (K1 and K201)
Each load contactor contains a magnetic operating coil and four sets of contacts. The three larger
contacts conduct three-phase AC generator output. A small contact set is connected to the Digital
Control PC Board (CTL) to activate the protective monitor circuit. Three-phase, 400-Hz generator
output power is distributed to the load contactor by 2/0 cables that pass through current transformers.
b) Current transformers (CT1-CT3 and CT4-CT6)
On each individual output a set of current transformers are used to monitor and control the line-drop
compensation, ammeter, and overload circuit.
(1) Line-Drop Compensation
The current transformers detect the magnitude and power factor of current flowing from generator
to load. They feed a signal to the voltage regulator that interprets the signal and alters the exciter
field current as required to maintain a constant predetermined voltage at the load.
(2) Ammeter
The current transformers convert a current signal to a voltage signal, which is sent to the Voltage
Regulator PC Board (REG). The ammeter is really a voltmeter graduated and numbered in
amperes to show current proportional to the voltage signal received.
When there is overload on the output for more than 5 minutes (load exceeding 326 amperes per
output or 125% of rated load), the main overload sensing circuit sends signals the load the
contactor circuit to open the load contactor.
(3) Overload, No 1 and/or No. 2 output
On each individual output the current transformers converts a current signal to a voltage signal.
The voltage signal is sent to the ammeter and to the overload monitoring circuit for that output.
The overload monitoring circuit will open the contactor when the output current reaches 125% of
the normal rated output current. The monitoring circuit monitors each individual output, as well
as, the overall current for a dual output machine.
The following is a list of overload module characteristics:
•
At 125% load the module will function in 5 minutes.
•
At 150% load the module will function in 30 seconds.
•
AT 200% load the module will function in 10 seconds.
May 2, 2013 Chapter 1-1
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