Overload Module; Rectifier - Hobart 6921 Series Operation And Maintenance Manual

OM-2040 / Operation and Maintenance Manual
90D20 / Generator Sets
The solid-state circuitry is designed to close the relay contacts when output current in ANY
phase reaches 125% of normal, rated output capacity. The closed relay sends a signal to the
protective monitor. This signal "gates" the overload SCR (silicon-controlled rectifier) in the
protective monitor and interrupts the load contactor to open.
The following is a list of overload module characteristics:
NOTE: The overload protective system will function when any phase carries 123% to 127% of rated
current.
At 125% load the device will function in 5 minutes.
At 150% load the device will function in 16 seconds.
NOTE: All times are plus or minus 25% and are nonadjustable.
1. Overload Resistor (16.6 Ohm, 25 Watt
for 90-kva)
2. Terminal Board
3. Overload Current Transformer
4. Ammeter Current Transformer

5. Rectifier

Chapter 1-1
Page 22
6. Load Contactor

7. Overload Module

8. Line Drop Resistor (50 Ohm,
25 Watt)
9. Line Drop Current Transformer
10. Blocking Diode
Power Module Panel Assembly
Figue 14
February 28/94
Revised