B. Braun Aesculap ElanEC GA835 Serviceanleitung Seite 31

ELANEC GA830 / GA835
re. b) Power supply of controls and regulating unit
The rectified secondary voltage from Tr2 is forwarded to
the switching controller U2 in order to generate a
stabilized direct voltage of 12V.
The secondary circuit from Tr1 is protected with fuse F2
(T0.2A).
7 7 7 7
Caution!
Electric shock hazard!
In case of measuring being carried out on an open
device, the device must be operated with an isolating
transformer.
Checking the mains part
Measuring points: P14-1: reference potential GND
P14-2 : approx. 30V - 35V
P14-3: square wave voltage U2
P14-4: +12V
re. c) Power supply of motor :
RT1 limits the starting current. Depending on the setting
of the voltage setting device in the combined net input
element, the mains voltage is rectified (set to 230V) or
rectified and doubled (set to 110V). The motor will thus
have a constant supply of approx. 200-250V (DC).
7 7 7 7
Caution!
Electric shock hazard!
In case of measuring being carried out on an open
device, the device must be operated with an isolating
transformer.
Checking the power supply to the motor
Measuring points: P14-1: reference potential Gnd
D - Q11A: 250 - 330V (DC)
Measurement taken from stopped motor.
(Q11A = left MOSFET on heat sink
D = middle pin of Q11A)
re. g) Power stage
Checking the power stages - FETs
Prior to measuring, the device must be disconnected
from the mains!
For a quick check of the functioning of the FET, the
resistance between the drain and source connections can
be measured, using an ohmmeter. For correctly working
FETs, a value of approx. 2M Ω or higher should be
measured.
The resistance of failed Fets is considerably lower
( < 100 Ω ).
GB
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