Siemens SINAMICS DCM Operating Instructions Manual page 135

Figure 6-40
The pulse shape of the current depends on the length of the cable to the thyristor
(cathode/gate). Cable inductance causes the rising edge of the current pulse to become
slower as the cable length increases.
Relationship between firing current and output voltage (incl. tolerances):
Application
The firing condition for the thyristor used (minimum firing current) must be to the left of the
firing circuit characteristic. The firing current can be determined graphically by finding the
point at which the thyristor's input characteristic intersects with the firing circuit's output
characteristic. It is important to remember that the thyristor's gate/cathode voltage drop
increases as the temperature decreases.
Examples of oscillograms
Firing voltage = gate/cathode voltage with 1 m twisted cable from the firing current circuit to
the thyristor's gate connection
SINAMICS DCM Control Module
Operating Instructions, 06.2010, C98130-A7067-A1-02-7619
6.16 Connector assignment (terminals, Faston mounting tabs, ribbon cables)
Firing pulse - time sequence
①
Normal working range of the thyristors is 1 to
4.2 V
No-load voltage = 7.8 to 8.4 V
Short-circuit current = 1.15 to 1.25 A
Connecting
135