Honeywell CD3000M-1ph User Manual page 29

Honeywell
7. Thiristor firing mode
ZERO CROSSING
VOLTAGE SUPPLY (V)
LOAD VOLTAGE (V)
SSR from controller
VOLTAGE SUPPLY (V)
ON OFF
SOFT
VOLTAGE SUPPLY
START
LOAD VOLTAGE
FIRING SIGNAL
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CD3000M-1PH up to 110A
20%
50%
70%
100%
20%
VOLTAGE SUPPLY (V)
50%
70%
100%
7.1 Zero Crossing (ZC)
ZC firing mode is used with Logic Output
from temperature
Thyristor operates like a contactor. The Cycle
time is performed by temperature controller.
ZC minimizes
Thyristor unit switches ON-OFF at zero
voltage.
7.2 Single Cycle (SC)
It's the fastest
method in respect to the power demand
from a temperature controller or an external
signal. At 50% input signal is one cycle ON
and one cycle OFF. At 75% is 3 cycles ON-
one cycle OFF. If power demand is 76% the
unit performs like for 75% but every time
that switches ON the microprocessor divides
76/75 and memorizes the ratio and when the
sum of rest is one the unit deliveries one
cycle more to the load. With this firing is
necessary to have analog input.
7.3 Burst Firing (BF)
This firing performed in Digital mode in our
Thyristor unit gives a lot of advantages
because switches Thyristor at zero voltage
crossing without EMC interferences. Analog
input is necessary for BF and can be decided
how many complete cycles we want at 50%
of power demand. This value can be
implemented from 1 to 255 complete cycles
doing the firing less or more fast. When 1 is
setted the firing name becomes Single Cycle
(see above).
7.4 Soft Start + Burst Firing
(S + BF)
This is an additional feature to Burst Firing.
The unit start in phase angle mode with a
ramp starting from zero up to full voltage in
a presetted and Adjustable time. After which
the rest of ON period will be at full
conduction. This firing S+BF is used to
switch ON small inductive loads to avoid
inrush surge current and to reduce at
minimum electrical interferences.
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User's Manual
controllers and
interferences because
zero crossing switching
the
the