Low Speed / Dual Speed Starter - CPI Indico 100 Series Service And Installation Manual

7
Theory of Operation
7.1.2 High Voltage Power Supply (Cont)
The power supply includes the following major subassemblies:
•
Integral to the high voltage power supply is the resonant circuit board. This assembly includes a
current transformer used to control and protect the inverter modules, an output common mode choke
for the inverters, and resonant inductors to optimize the inverter performance.
•
The HT oil tank consists of high voltage transformers, filament transformers, high voltage rectifier
power boards, tube selection relay on two tube tanks, and feedback circuits for the output kV and mA.
The high voltage tank is capable of producing exposures of up to 80 kW and output voltages of up to
150 kV, depending on model.
•
The power supply control board contains the feedback and control circuits for the high voltage tank as
well as the over-voltage and over-current detection, and arc protection circuits. It also contains a
voltage controlled oscillator for the gate pulse generator, which drives the FET's of the inverter
module. This board connects to the control electronics through 37 pin and 15 pin D-connectors
providing the transmission of key control signals between the power supply and the control
electronics.
•
The power supply control board contains the feedback and control circuits for the high voltage tank as
well as the over-voltage and over-current detection, and arc protection circuits. It also contains a
voltage controlled oscillator for the gate pulse generator, which drives the FET's of the inverter
module. This board connects to the control electronics through 37 pin and 15 pin D-connectors
providing the transmission of key control signals between the power supply and the control
electronics.
•
The power input board has the principle function of converting the mains power to a high voltage DC
bus, which in turn provides the energy to the inverter modules. This board also contains other high
voltage circuits, such as those for the soft start relays, the main contactor, and the EMI line filter
components. The power input board has the principle function of converting the mains power to a high
voltage DC buss, which in turn provides the energy to the inverter modules. This board also contains
other high voltage circuits, such as those for the soft start relays, the main contactor, and the EMI line
filter components.
7.1.3

Low Speed / Dual Speed Starter

•
The low speed starter uses thyristor control to deliver nominally 240 VAC for a boost period of
approximately 1.2 seconds. This boost period is required to get the anode of the tube up to speed at
around 3200 rpm. At completion of the boost time, the stator voltage will be reduced to approximately
50 V for the run period, during which the correct tube speed is maintained for the length of the X-ray
exposure.
•
The dual speed starter uses a microprocessor controlled IGBT inverter to provide programmable
boost and run voltages and programmable boost times to the stator windings of the X-ray tube. The
DSS supply can operate at low speed (50 or 60 Hz) or high speed (150 or 180 Hz) and also provides
DC braking. With microprocessor control, the DSS is able to maintain precise control of the rotor
supply functions, which enables stable and optimum performance of the tube at either low or high
speeds.
Page 7-4 Rev. A Indico 100 Series Service Manual
CPI Canada Inc
Ch # 740895-06