Siemens SINAMICS DCM Operating Instructions Manual page 151

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
A Substitution load 20 Ω in parallel with 2 diodes
B Substitution load 20 Ω in parallel with 4 diodes
①
Control signal
②
Voltage at load (0.5 V/div)
③
Current through load (0.5 A/div)
Figure 6-46 Firing pulse – Oscillograms
SINAMICS DCM Control Module
Operating Instructions, 12/2018, A5E34888669A
6.16 Connector assignment (terminals, Faston mounting tabs, ribbon cables)
①
normal working range of thyristors is from 1 to
4.2 V
No-load voltage = 7.8 to 8.4 V
Short-circuit current = 1.15 to 1.25 A
Connecting
149