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3.1.5 Diode Assembly
The diode assembly of the converter is completely solid state employing parallel sets of silicon
diodes as the rectifying elements. See
Figure 14 . A six-phase single way rectifier connection is
employed.
The shunt provides the current feedback for the control and also the signal for the indicating
ammeter. The DC voltage output provides the voltage feedback for the control.
3.1.6 Control Transformer
Steps down the primary line voltage to 110 Volts for use in the control circuit.
3.1.7 Protective Devices
These devices provide protection for the converter.
A. Main Line Overload
A thermal type relay which opens when excessive current is drawn from the main line by the
converter. A normally-closed contact in series with the starter or contactor magnetic coil will open,
de-energize the coil and drop the converter off the line. The relay contacts must reset before the
converter can be re-started. A starter will have the thermal overload relays integral to the starter
while a contactor will use current transformers and separate overload relays.
Figure 14 Diode Assembly