REVEX
1PH from 120A to 210A
User’s manual
57
13.4 Soft Start with Burst Firing
This is an additional function to the
Burst Firing. The unit start in phase
angle mode with a ramp starting from
zero up to the full tension in the cycles
number set in the parameter.
When the ramp is over, the thyristor
unit will stay in conduction at full
voltage up to the end of cycles of
burst. The S+BF firing is used to control
small inductive loads to avoid inrush
surge current and to reduce the
electromagnetic interferences.
The example show the firing with Burst
cycles =4 and start ramp half cycles=3.
13.5 Phase Angle
The Phase Angle firing allow the control
of the power on the load, for this firing
the thyristor can be in conduction only
for a part of the voltage cycle.
This part of the voltage cycle is
adjustable in function of the input signal
from 0 at 100%.
The PA firing is normally used for control
the inductive loads, and is also possible
control a primary of transformer
coupled with the cold resistances like:
Superkanthal, Molybdenum, Platinum,
Tungsten or Quartz Lamp. The only
disadvantage with phase angle is the
possible generation of interferences
that however can be reduced with opportune filters.
13.6 Soft Start with Phase Angle
This is an additional function to the
Phase Angle. The firing angle of the
thyristor increase or decrease up to the
final setpoint value.
The Soft start ramp is an important
feature to reduce the inrush current
with transformers during the cycle of
magnetization or with cold resistance
that are near to the short circuit when
they are supplied.
Setpoint Ramp Up / Setpoint Ramp
Down.
25%
50%
75%
100%
Voltage Supply (V)
Load Voltage (V)
ON
OFF
25%
50%
75%
100%
Voltage Supply (V)
Load Voltage (V)
ON
OFF
Setpoint Value (%)
Load Voltage RMS (V)
Ramp Up
Ramp Down
Voltage Supply (V)
Output Voltage (V)
ON
OFF
