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Siemens-Elema AB Register 6 SPR8-215.850.02 Page 1 of 2 MOBILETT Plus/ Plus E
Solna, Sweden Rev. 01 01.02 SPS-UD
Rotating-Anode Starter 14
The block diagrams and the wiring diagram SPR8-220.051..., sheet 150, are the basis of
the functional description given below.
The circuit for the rotating-anode consists of the boards D1, D4 and D8 and the stator of
the single-phase asynchronous motor of the rotating anode in the single tank, H1.
The inverter for the rotating anode has four POWER MOS-FETs as a square wave
inverter on board D4.
The inverter is supplied with 100 V DC from board D8.
This voltage can be measured between the test points "100 V DC" and "100 V DC RET"
on board D4.
The inverter on board D4 is controlled by the SAB 80 C535 CPU on D1. Two180° phase-
shifted signals (fig.1) "ROT A" and "ROT B" on board D4 generate the speed for the rotat-
ing anode with a boost of power in a time of 2 s.
The power from the inverter feeds the two windings of the single-phase asynchronous
motor via the cable "K61".
A phase-shift capacitor is in series with the auxiliary winding of the motor. The phase-shift
capacitor connects via cable "K66" board D4 and the auxiliary winding of the motor.
The phase shift between main and auxiliary winding is 90°. This is necessary to enable
rotation with the maximum torque.
To get the rotating anode up to speed a control signal with a frequency of 160 Hz
1
is
applied to the two test points "ROT A" and "ROT B" on board D4.
The run-up-time requires two seconds. After this the control signal is switched off and the
anode runs freely. If the anode looses speed and a frequency <147 Hz
2
is measured, the
anode is accelerated for 0,75 s. These additional "pushes" are repeated, if necessary,
until the limit of the preparation time (20 s
3
) or until the release of an exposure. A push is
interrupted if an exposure signal is made.
The free running anode motor acts like a generator. It produces a remanence voltage
which is detected by a transformer on board D4.
Fig. 1
1. 150 Hz if FW version is lower than V1.5 or V1.5E.
2. <142 if FW version is lower than V1.5 or V1.5E.
3. 10 s if FW version lower than V1.2 or V1.2E.
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