Siemens MOBILETT Plus Manual page 43

High-voltage circuit
The block diagrams and the wiring diagram X037E, sheet 140 are the basis for the func-
tional description given below.
The high voltage circuit includes:
•
the capacitor bank, M1,
•
the CPU board D1,
•
the high-voltage inverter board D13,
•
the single tank H1
The high-voltage inverter on board D13 includes eight power MOS-FETs and functions as
a square wave inverter.
It is supplied with power from the capacitor bank, M1, with power and with control pulses
in the frequency range 20 - 50 kHz to control its function from microprocessor SAB
80C166 on the CPU board D1.
The pulse-pause ratio of this control frequency is modulated by the microprocessor on the
CPU board D1.
It is possible to measure the control frequency at the test points "INV A" and "INV B" on
board D13.
The high-voltage inverter drives a DC voltage of alternating polarity via the primary wind-
ing of the single tank H1.
The secondary winding of the single tank H1 transforms these current pulses into high
voltage and a voltage doubler circuit generates their final value.
Fig. 1
Siemens-Elema AB
Solna, Sweden
Register 6 SPR8-215.850.02
Rev. 01
Page 1 of 4
01.02 SPS-UD
15 - 1
15
MOBILETT Plus/ Plus E