Dynalyzer – High Voltage Unit
OPERATION MANUAL
4
Introduction
General
The Dynalyzer IV High Voltage Unit is capable of providing isolated signals analogous to:
1. Anode, Cathode, and Anode + Cathode kilovoltages
2. Anode
Current
3. Filament Current (AC)
These signals may be viewed on an oscilloscope, may be measured with Accu-Dyn+ system,
peak measuring voltmeter or may be processed and displayed with the Dynalyzer Digital Display
(obsolete).
This unit has been designed as a calibration instrument and as a diagnostic tool for servicing x-ray
equipment.
This unit is designed for continuous duty, and may be left in the high-voltage circuit indefinitely, if
desired. This feature is desirable in special applications where frequent calibration is required.
This unit is portable. It weighs 32 pounds and is designed to simplify servicing and repair.
Basic Principle of Operation
The Dynalyzer High Voltage Unit is built in two sections. All high-voltage components are located
in a tank pressurized with 30 psig of Sulfur Hexafluoride (SF
6
) gas. In the base of the unit are
power supplies and buffer amplifiers to adjust the levels of the isolated signals, provide buffering
against cable and instrument loading effects, and provide frequency compensation. In addition,
there is an oscillator which in conjunction with a high-frequency isolation transformer located in the
tank, provides power to operate the anode current sensing system.
Anode Current Sensor
The anode current sensor is an optically-coupled device that is capable of providing an isolated
signal that represents the anode current waveform. The sensor is capable of measuring current in
the range of 1 mA to 2 Amperes with a 2% absolute accuracy ± zero offset. The output conversion
factor is 1 mV/mA for radiographic and 20 mV/mA for fluoroscopic measurements. The insertion
impedance of the unit is 42 ohms ± 5%. The average power rating of this resistor network is 40
watts, and is the only duty cycle limitation on this unit. The duration should not exceed 1 second at
1000 mA.
High-Voltage Divider
The divider consists of two 1000 mega-Ohm sections that are connected between the anode and
ground, and cathode and ground. Each section contains five 200 megaohm resistors connected in
series. The geometry of the structure provides distributed capacitance that provides a frequency
response of 100 kHz.
