Date post: | 01-Apr-2015 |
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High Voltage Supply
High voltage SuppliesGenerators should provide a smooth constant high voltage to the X-ray tube.
Transformers
ondary
primary
ondary
primary
V
V
number
number
secsec
Step up transformers
Nprimary= 100 Nsecondary = 50000
V primary = 240V V secondary = 120 kV
N primary
N secondary
Single phase Full Rectification
High frequency power supplies
Modern High Voltage supplies use a high high frequency chopped DC voltage (500V) which is transformed to a high voltage (74kV) The 500V DC signal is chopped at between 20kHz and 30 kHz and transformed using a step up transformer to 74kV. The smoothed supply may have a ripple of below 3%
A Typical Frequency Generator : HSA RPKilovolts kV selections: 80,1 00,120, and 140 kV
Basic kVp Accuracy: + 3% +/- (3% + 2kV) Excludes first 10msec of exposure
kVp during first 10 ms: Basic accuracy +/- 5 kV
Milliamperes mA selections: 40 to 400 mA, by 10 mA increments
Patient scanning subject to tube limitations and 48kW maximum
Chopped 550 Supply
Resonance Voltage Control