GE_OEC_9600_C-Arms

kV Generation 11
NOTE
If the secondary TAP1 and TAP2 signals carried through P4 on the X-ray Regulator
PCB are disconnected, pull-up resistors R90 and R100 will cause comparator U16
to trip the OVERVOLTAGE line. This is an important safety factor: all signal lines on
P4 must be connected for the Generator to operate without damage.
OVERLOAD FAULT
Peak currents in excess of 200 Amps in the primary winding of the high voltage tank
define an Overload Fault. If a fault occurs, the message OVERLOAD FAULT is
displayed on the Control Panel. This is a fatal error resulting in a system shutdown,
preventing X-rays.
Overload Fault Circuit
A sense winding is incorporated in the output-tuning inductor L1, in series with the
primary winding of the high voltage transformer which senses the differential voltage
across the inductor. This CURRENT LOOP signal is sent to the X-ray Regulator PCB on
P2-3 where it is integrated by R7 and C9 to derive a voltage proportional to the current
through L1. This voltage can be measured on TP1.
This voltage is monitored by comparator U1-2 and compared to a reference voltage of
approximately 1.6 VDC applied to U1-3. This reference voltage is the comparator’s
threshold, representing the maximum primary input current allowed for safe operation.
When the voltage on U1-2 exceeds that of the voltage on U1-3, the output on U1-7 goes
high indicating an Overload condition. This logic high is felt at the fault PAL U2-2
causing the PAL’s outputs U2-17 (OVERLOAD) and U2-13 (FAULT) to also go high.
The logic high FAULT output of Fault PAL U2-13 prevents X-rays by disabling the
HVDRVA and HVDRVB signals from the high voltage drive PAL U7.
The logic high OVERLOAD output of U2-17 and the logic high FAULT output of
U2-13 are also monitored by the Technique Processor PCB via the Analog Interface PIO
U27. This condition is a fatal error and causes a system shutdown. The message
OVERLOAD FAULT is displayed on the generator control panel display.
KV ON IN ERROR MESSAGE
With no X-ray switch engaged, the Technique Processor software detected voltage on
the KVP MEASURED line indicating high voltage was present but not commanded. The
message is displayed and the system is shut down.
HIGH KV AND LOW FLUORO KV ERRORS
The detected kV (KVP MEASURED) and the selected kV technique do not agree within
20%. The message is displayed and the system shuts down for two seconds after the
exposure.