X-ray generate supplies electric power of required amount to X-ray tube.

Works over two separate components

• Control panel or Console
• Transformer assembly

Console panel is to control kVp, mA, & exposure time.

Transformer assembly contains

• High voltage transformer circuit (auto &step up transformer)
• Filament circuit ( Auto &step down transformer)
• Rectifier

•A device that either increase or decrease the voltage in a circuit.

•Receives 115V-220V, 60-Hz cycle per second of A.C.

• FILAMENT heating requires a potential difference of 10V.

•ELECTRON ACCELERATION requires a potential difference of b\w 40,000-1,50,000V

(Transformer to change the potential difference of incoming electric energy to required level.)

•Current flows in secondary coil only when magnetic field is increase or decreases.

•Alternating current is used in transformers because it is produced by potential difference /voltage that change continuously in magnitude and polarity.

•Voltage change with change in flow of current.

•If current flow in one direction, voltage is positive.

•If current flow in opposite direction voltage is negative.

•The major characteristic of  alternating current is that it’s voltage change continuously that produces a continuous change in magnetic field.

•Therefore an alternating current in the primary coil of transformer produce an alternating current in secondary coil.

Laws on which working of transformer is based on are:-

1. Law of conversion of energy
2. Faraday’s law of induction

1. LAWS OF CONVERSION OF ENERGY

Transformer never create energy. Increase in voltage is accompanied by decrease in current.

                VP IP=V S IS

VP  =Voltage in primary coil

IP = Current in primary coil

V S  = Voltage in Secondary coil

IS. = Current in Secondary coil

2. FARADAY’S LAW OF INDUCTION

•Voltage in two circuits is directly proportional to the no of turns in two coils.

                           NP/NS.  =   VP/VS

NP = No. of turns in primary coil.

NS = No. of turns in secondary coil.

VP = Voltage of Primary coil

VS = Voltage in secondary coil

EFFICIENCY

•Efficiency of transformer is the ratio between output power over input power. •

    Efficiency = output power/Input power

•A transformer core are always designed so that they form a closed circuit so that magnetic circuit has high high permeability.

•Core is laminated to eliminate eddy current loses.

•Types of core

1. Core type
2. Shell type
3. Cross/H – type

Transformer are classified in 3 types

1. Step-up
2. Step-down
3. Auto transformer

•It works on the principle of mutual induction.

•Used for increase the voltage.

•Output Voltage in higher than input voltage.

Construction :-

•Coil is wind around the core bar separately.

•No. of turns in secondary coil is higher.

Working 

• Voltage transformation depends upon no of turns in primary and secondary coil.
• Higher the no. of turns in secondary coil, higher will be emf in secondary coil.
• It increase output voltage.

.Function 

• Use in high voltage transformer circuit.
• Conversion of 220V of input voltage into 40,000-1,50,000 V.

• Work on the principle of mutual induction as well.
• Used to decrease voltages.
• Input voltage is higher than output voltage 
• Construction:-
  • 2 separate coil wind around core.
  • No. of turns in secondary coil is lesser than primary coil.

Working 

• Current induce to primary coil, creates magnetic flux.
• Due to lower turns in secondary coil, flow of voltage would be slower.

Function 

• Provide voltage to filament circuit of X-ray generator.
• Convert 220v of input voltage to 10V.

• Works on the principle of self induction.
• Can increase or decrease voltage as per requirements.
• Secondary coil turns adjustable.

Construction:-

• Single winding around around iron core.
• Primary circuit connect across the coil.
• Secondary coil have one common point with primary circuit.
• Other point of secondary coil is adjustable

Working 

• When current is induced to primary coil, magnetic field flow across the core.
• Magnetic flux will link with all turns forming the coil, including voltage into each turns of winding.

Example
If 230V are applied between  points A and B connect to  115 turns of the  autotransformer winding the  volts per turn will be 2

Function 

• Provide voltage for X-rays filament circuit 
• Provide voltage for primary coil of  high voltage transformer circuit.
• Convenient location for kVp controller that indicates voltage across X-ray tube.

• Copper loss
• Eddy Current loss
• Hysteresis loss
• Flux leakage .

Eddy current loss

• When magnetic field change, EMF induced to the core.
• Due to induced EMF to core, current flow in core.
• Core start getting heat cause Eddy current loss.
• Can avoid by using thin sheet of metal insulated with paper.

Copper loss

• When current flow through resistance, amount of power convert into heat.
• Copper is used for coil in transformer which is also act as resistance and get heated.
• By using thicker coil copper loss can be reduced.

Hysteresis loss

• When current induced to primary coil, iron core gets magnetised.
• Core magnetised twice in each cycle of a.c.
• Magnetisation reversed with change in polarity.
• Due to sudden reversal change of magnetic field, friction between molecules occur.
• This energy loss due to friction is Hysteresis loss appeared as heat.

Flux leakage

• All Magnetic flux linked with primary coil is not linked with secondary coil.
• It is said to be Flux leakage, results in loss of energy.
• Can be minimised using good core design like shell core.

THANK YOU

DROP A COMMENT BELOW

YOU CAN REQUEST A TOPIC ON MAIL AND AS WELL AS COMMENT BOX

STAY TUNED FOR MORE TOPICS LIKE THIS AND DON’T FORGET TO SUBSCRIBE US