Honeywell
CD3000S-3PH from 125A to 500A
User’s Manual
1. Glossary
1.1 Terminology
V:
voltage power supply.
I:
the full circulating current in thyristor unit.
P:
total load power.
1.2 Input signal
SSR:
This input type is a square waveform generated by a temperature controller.
AN:
Analog input.
IRS:
Communication command.
1.3 Power feed back
Feedback:
supply voltage fluctuation changes the power to the load. To overcome this effect the
voltage supplied to the load is measured and compared with power demand from controller, the
error signal is used to automatically hold the power at demanded level.
1.4 What is a thyristor unit
A thyristor unit is semiconductor device which acts as a switch formed by two thyristors in
antiparallel. To switch on the alternating current the input signal will be on and the thyristor will
switch off at first zero crossing voltage with no input signal. The benefits of thyristor units
compared with elettromechanical contactors are numerouses: no mooving parts, no maintenance
and capacity to switch very fast. Thyristors are the only solution to control transformers and
special loads that change resistance with temperature and with age.
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