Operating instructions

16
SOFT-START-SOFT-DOWN (SSSD)
The operating mode SSSD operated similar to operating mode TAKT. However, it can be used
especially advantageous in operation of large single loads to reduce pulse-shaped mains loads and
therefore to reduce voltage variations. Switching on and off of turn on-time Ts occurs by applying
periods with phase-angle firing (VAR). Please see following diagram.
Key parameters are
TAKT cycle period T
0
[sec]
Soft-Start SST [msec]
Soft-Down SDN [msec]
MOSI operation for 1P and 3P
MOSI is a sub-operating mode of the operating modes TAKT and VAR for sensitive heating ma-
terials with a high R
hot
/R
cold
ratio, for instance molybdenum disilicide. The Power Controller always
starts with phase-angle maximum value and actual value to avoid high current amplitudes during
the heating-up phase and then automatically switches to the set operating mode.
For the sub-operating mode MOSI, the key parameters are:
MOSI: RAMP/ STELL
Rate of angular displacement 1 [°el/s]
Rate of angular displacement 2 [°el/s]
Peak current
I max [A]
MAINS LOAD OPTIMIZATION (WITH dASM OR OPTIONAL ASM PROCESS)
For systems in which several power controllers are employed in full wave switch mode TAKT, it is
possible that individual power controllers are synchronized so that a regular mains load is achieved
by defined switching of the individual power controller. This avoids load peaks by random simulta-
neous switching of many power controllers and load troughs are filled up. The
upstream transformer and/or the upstream feed point may be designed for a lower load. Besides
savings in investment and operating costs it also results in considerable lower system perturbations.
For new installations the dASM process is recommended due to its quicker and easier handling (see
chapter 6.1).
2.2 SET POINT CONTROL CHARACTERISTIC
The set point control characteristic of Thyro-P may be easily adapted for the control output signal
of the upstream process controller or automation system. All signals customary on the market may
be used. The adaption is made by changing the starting and ending points of the control characte-
ristic. Inverted operation (ending value is smaller than the starting value in voltage or current) is also
possible.
The effective set point is the total set point. It is formed by adding the four set points as shown in
fig. 2.
In the simplest case all the set point values are added algebraically. The prerequisite for a set point
to influence the total set point value is that it must be enabled by the set point Enable Register.
• Set point 1 (X5.2.10 - X5.1.13 ground) 0-20mA default