Pre-Operation Checks; X-Ray Tube Conditioning Procedure - Varian B-100 Manual De Instrucciones

D. Spotfilm Operation
1. When spotfilm work is part of the fluoroscopic system, it is recommended that the stator not go through another
starting cycle each time a transfer is made from fluoroscopic operation to spotfilm radiography. Use 60 second
holdover after 150/180 Hz. selection.
E. Angiography
1. Use 150/180 Hz. for Angiography.
1.6 PRE-OPERATIONAL CHECKS
A. Connections: Insure that all the connections are properly made and tight before applying high voltage to the tube
housing assembly.
B. Rotation: Target rotation direction is dependent upon rotor/rotor controller combination.
C. Stator Connection: The correct stator connections can be determined by measuring the current between the black and white
leads. The current should be 4.0 Amps nominal with 120 volts - 50/60 Hz and 7.5 Amps nominal with 230 Volts -50/60 Hz.
Be advised that the stator may emit some electromagnetic forces (EMF) by nature of its construction. In the system
application, Varian recommends the thorough testing for the EMF from the x-ray tube housing assembly as it may cause
interference with other electronic devices.
D. Power Cord: Some tube housing assemblies have a five wire power cord with a braided shield, this should be identified
and properly attached to the housing assembly before operating. Instructions for attachment are shown on the stator tag.
Three of the five wires supply power to the stator and the other two are used for an over-temperature thermal switch.
E. Thermal Switch: The use of the thermal switch is mandatory in a warning circuit or interlock. If the housing should
overheat during operation the resulting expansion of oil cannot be completely accommodated by the rubber diaphragm.
The risk of injury exists if the diaphragm is ruptured or forces the end cap from its intended position as a result of
overHeating.
Note: The thermal switch does not detect or directly measure the anode target temperature.
F. Thermal Switch Connection: The thermal switch must be connected as an interlock to prevent exposure and/or provide
a visual or audible warning in an overheated condition. The switch is normally closed but opens when the temperature
rises above the housings rated value. Do not connect the thermal switch in series with the stator leads or in any manner
beyond their rating.
G. Cooling: Operation of the x-ray tube must cease immediately if the thermal switch opens. A cooling device, such as an
air circulator or oil heat exchanger, must be left running if the thermal switch opens. Power to the stator must also be
turned off to allow the tube unit to adequately cool. Operation of the tube housing assembly must not be initiated until
the thermal switch has returned to the closed position.
1.7 X-RAY TUBE CONDITIONING PROCEDURES
A. Consult the equipment manufacturer's instructions for tube conditioning procedures. the following can be used as a
recommendation if no tube conditioning procedures are provided.
B Newly Installed Tubes and Daily Warm-up
1. To season or condition X-ray tube, start with the lowest mA station available on the X-ray control for the large
focal spot and make the following exposures:
Begin with 80 kVp, 1/10 second for three exposures.
Raise to 100 kVp, same mA and time for three exposures.
Raise to 125 kVp, same mA and time for three exposures.
X-RAY
PRODUCTS
X-RAY TUBE ASSEMBLY AND
INSTALLATION MANUAL
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