Measuring The Oscillating Current - Siemens POLYMOBIL Plus Service Instructions Manual

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Measuring the oscillating current

WARNING
•
Switch OFF POLYMOBIL Plus and wait until the capacitor voltage has dropped to a
value < 10 V.
•
Disconnect the cable from the inverter to capacitor C1 and push the cable through the
current transformer 50 A : 50 mA (with a parallel resistor of 10 ohms) and connect the
cable again.
•
Connect the oscilloscope to the current transformer.
•
Switch ON POLYMOBIL Plus .
•
Set 60 KV, 10 mAs on POLYMOBIL Plus and release exposure.
The diagram must correspond to Fig 8.
CAUTION
CH2: 1 V/Div, Trigger: Test point "TRG" external on D 915
20 µs /Div
Fig. 8
POLYMOBIL Plus
Prior to beginning the following instructions, you must discharge
the capacitor bank, because life-threatening DC voltage is
present. Check the actual charge with the DVM.
The maximum main inverter frequency can only be measured in
the ascending part of the high voltage, i.e. in the first microsec-
onds, because afterwards the frequency is lower.
SPR8-125.061.02
Rev. 01
Page 8 of 20
01.00 TD SD 24
Measurements
Siemens AG
Medical Engineering
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