Siemens MOBILETT Plus Manual page 42

14 - 2
Stator voltage from generator
Pulse frequency at "ROT VAL"
Pulse frequency at "ROT"
Between run-up and
normal running
Fig. 2
The frequency of this voltage represents the momentary speed and it is monitored from
the CPU during the entire free run. The frequency reached can be checked (fig.2) at "ROT
VAL" on board D4 or at "ROT" on board D1.
At test point "ROT", on the CPU board D1, the time between two pulse edges is the time
for a complete sinusoidal oscillation.
The pulse frequency is divided by 2 at test point "ROT" on D1. It is monitored at the same
time from the CPU on D1.
The anode is up to speed if the pulse frequency "ROT" is > 147 Hz
of 2 s.
If the frequency detected is below 147 Hz
and the reached speed will be measured again.
If the second try indicates that the required speed of 147 Hz
system generates the internal message "anode up to speed"! This completes the prepara-
tion together with exposure heating on.
The green "ready" LED on the Control and display panel turns on and the buzzer gener-
ates three beep tones.
The unit is now ready to operate!
After the exposure is terminated the anode-braking procedure starts. This is done with a
pulse frequency of 1.667 kHz by the CPU on board D1. It can be measured on test point
"ROT A" at board D4.
This frequency generates by one pair of MOS-FETs in the inverter a pulsed DC current for
both stator windings.
The magnetization in the stator and rotor winding produces an eddy current field which
slows down the speed of the rotor. The brake time to a full stop takes 9 s.
The braking procedure for the rotating anode is also active under following circumstances:
•
when switching on the unit,
•
if the operator interrupts an exposure preparation, or
•
if a system fault occurs.
1. 142 Hz if FW version lower than V1.5 or 1.5E.
2. 7 s if FW version lower than V1.4 or V1.4E.
MOBILETT Plus/ Plus E
Normal running
Register 6 SPR8-215.850.02
Rev. 01
Rotating-Anode Starter
1
the entire run-up procedure will be repeated
1
is now exceeded, the control
Page 2 of 2
01.02 SPS-UD
1
after the run-up-time
2
Siemens-Elema AB
Solna, Sweden