X-ray generators use transformers, rectifiers, and capacitors to convert electrical power into high voltage pulses needed to generate x-rays. There are several types of x-ray generators including single phase generators that produce two pulses, three phase six pulse generators that use three phase power, and three phase twelve pulse generators that add an additional delta connection to produce twelve pulses. High frequency generators use high frequency current to provide a constant voltage to the x-ray tube. Power discharge generators include capacitor discharge generators that use a high voltage capacitor to store and discharge charge, and battery powered generators that use batteries as the power source.

1. X-ray generators
Mr Sujan Poudel
B.Sc.MIT (2015)
Department of Radio Diagnostic and
Imaging

2. Outline
• Definition
• Components
• Types

3. Definition
Generators means an electrical device which
transform mechanical energy into electrical
energy.
But x-ray generator supplies electric power to
x-ray tube.
 x-ray generator begin with the source of
electrical energy.
Radiology department will have 3 phase power
available in range of 220V.

4. Components
Transformer
Rectifiers & capacitors
Subsidiary circuit

5. Transformer
Types of transformer used in x-ray equipment
Auto transformer
Filament transformer(step down transformer)
High voltage transformer(step up transformer)

7. Generators types
• Types
Single phase x-ray generator: uses single phase
voltage source(220V) and produces two pulse DC
waveform.

8.  3 phase six pulse generator: commercial
electric power is usually delivered as three
phase.

9. Contd……
phases 120o apart
Single Phase Power Three Phase Power

10. Contd..
Incoming 3-phase supply can be connected two
ways :
Star connection(wye connection):generally
secondary winding of transformer. It has 3 phase
and four wire system
In which one wire is earthed(zero volt)
So we can get line voltage ie 440 and phase
voltage ie 220v
Delta connection: generally primary winding of
transformer is delta connected

11. Rectifier
Convert AC into DC
PN junction is used as rectifier where P and N
are semiconductors
When +ve end is connected to P side and -ve
end is connected to N it is called forward
biased.

13. Working of Segment AB
• In 1st +ve half cycle when point A is (–ve) and B is
(+ve).
• Diodes R3 & R2 gets forward biased and R1& R4
gets reverse biased
• Flow of electron is from point A R3 Filament-
anode R2 finally to (+ve) terminal B
• In next (–ve) half cycle when point A is (+ve) and B
is (–ve)
• Diodes R1 & R4 gets forward biased and R3 & R2
gets reverse biased.
• Flow of electron is form point B R1 filament
anode R4 finally to (+ve) end A.

14. 3 phase 12 pulse x ray generator
To obtain 12 pulse from six phase an additional
delta connection is added on secondary
winding of transformer.
So delta lags wye by 300 that means in each
300 phase difference a pulse is obtained. So,
total 12 pulse can be obtained.

15. 4

16. Working of segment AB
• IN 1st +ve half cycle of AC input
• Suppose end A becomes +ve and end B
become –VE
• Diodes R1& R6 gets forward biased and diode
R5 & R2 gets reversed biased
• Flow of electron from point B R1
xraytube R6 and to point A.
• After 300 output of delta is given out
• End A’ is +ve and B’ Is –ve
• Diodes R1’ and R6’ gets forward biased and
diode R5’ and R2’ gets reverse biased.

17. Contd..
• Flow of electron point B’ R1’ x-ray tube R6’
to +ve end A’.
• In –ve half cycle of AC input end A becomes –ve and
B becomes +ve.
• Diodes R5 and R2 gets forward biased and diodes R6
and R1 gets reverse baised.
• Flow of electron from point A R5 x-ray tube
• R2 and finally to positive end B.
• After 3o degree delta circuit is activated.

18. Contd…
High frequency x-ray generator:
uses high frequency
current to provide constant voltage to the x ray
tube.
Principle:
when high frequency current is fed to
primary winding of transformer it cause change in
magnetic flux which produces high voltage EMF in
secondary winding of transformer.
Output voltage obtained i.e V is directly
proportional to frequency to ac
No of turns of transformer
Area of iron core

19. Block diagram of high tension
transformer

20. Advantages
Independent of input power supply i.e it can
operate either in single phase input or 3 phase
input
Has less ripple factor ie (1%)
Compact in size so can accommodate in x ray
tube housing

22. Power discharge generators
Types
Capacitor discharge generator:
It uses high voltage capacitor
to store the charge and when exposure is done
discharging of capacitor occurs.
Battery powered generator:
It uses Ni-CD batteries to
supply input power to x ray tube.

23. Working
• DC supplied by nickel caddmium batteries
inverter high frequency AC
Transformer high voltage AC
Rectifiers high voltage pulsed DC
Capacitor high voltage smooth DC
X RAY TUBE
USES
• Used in mobile x ray unit for ward radiography.