Presentation is loading. Please wait.

Presentation is loading. Please wait.

Rad Physics Prof. Stelmark

Similar presentations


Presentation on theme: "Rad Physics Prof. Stelmark"— Presentation transcript:

1 Rad Physics Prof. Stelmark
Rad Physics Review 2 Rad Physics Prof. Stelmark

2 Rad Physics Prof. Stelmark
Transformers Rad Physics Prof. Stelmark

3 Rad Physics Prof. Stelmark
A transformer changes the intensity of alternating voltage and current. Rad Physics Prof. Stelmark

4 Rad Physics Prof. Stelmark
Mutual Induction Rad Physics Prof. Stelmark

5 Rad Physics Prof. Stelmark
Transformers A device in which two coils are placed near one another without electrical connection. The number of turns in the coils differs, causing a change in currnet in the secondary coil; this serves to either increase or decrease the voltage. Rad Physics Prof. Stelmark

6 Rad Physics Prof. Stelmark
Rad Physics Prof. Stelmark

7 Rad Physics Prof. Stelmark
Types of transformers Air core Open core Closed core Shell type Rad Physics Prof. Stelmark

8 Rad Physics Prof. Stelmark
Air core transformer Rad Physics Prof. Stelmark

9 Rad Physics Prof. Stelmark
Open core transformer Rad Physics Prof. Stelmark

10 Closed core transformer
Rad Physics Prof. Stelmark

11 Shell type transformer
Rad Physics Prof. Stelmark

12 Rad Physics Prof. Stelmark
Step up vs Step-down Rad Physics Prof. Stelmark

13 Rad Physics Prof. Stelmark
If you increase the number of turns on the right, the voltage coming off the transformer will increase in proportion. Using the numbers in the example above, you can see that the right side has four times more turns. As a result, the voltage on the right has increased four times (from 100 V to 400 V). The voltage has been stepped up by a factor of four. Because current is inversely proportional to voltage, you can see that stepping up the voltage pays a price ... the current on the right is only a quarter of what it was on the left. Step-up transformers increase the voltage, but decrease the current. In our example above, the current went from 10 A to 2.5 A, a reduction of by a factor of four Rad Physics Prof. Stelmark

14 Rad Physics Prof. Stelmark
If you decrease the number of turns on the right, the voltage coming off the transformer will decrease in proportion. Using the numbers in the example above, you can see that the right side has one fifth the number of turns. As a result, the voltage on the right is only one-fifth as large. The voltage has been stepped down by a factor of five (1000 V down to 200 V). Because current is inversely proportional to voltage, you can see that stepping down the voltage gives a bonus ... the current on the right is five times what it was on the left. Step-down transformers decrease the voltage, but increase the current. In our example above, the current went from 2 A to 10 A, an increase by a factor of five. Rad Physics Prof. Stelmark

15 Rad Physics Prof. Stelmark
Transformer law Rad Physics Prof. Stelmark

16 Rad Physics Prof. Stelmark
Ns Np If the turns ratio is greater than 1 the transformer is a step-up transformer. If the turns ratio is less than 1 the transformer is a step-down transformer Rad Physics Prof. Stelmark

17 Autotransformer (kVp selector) self-induction
Rad Physics Prof. Stelmark

18 Rad Physics Prof. Stelmark

19 Rad Physics Prof. Stelmark

20 Rad Physics Prof. Stelmark
RECTIFICATION Rad Physics Prof. Stelmark

21 Rad Physics Prof. Stelmark
X-RAY CIRCUIT Rad Physics Prof. Stelmark

22 Rad Physics Prof. Stelmark
RECTIFICATION PROCESS BY WHICH ALTERNATING CURRENT IS CHANGED TO PULSATING DIRECT CURRENT Rad Physics Prof. Stelmark

23 ALTERNATING CURRENT 1 PHASE
A/C ( UNRECTIFIED)- FREQUENCY 60 Hz Rad Physics Prof. Stelmark

24 Rad Physics Prof. Stelmark
60 POSITIVE PULSES/SEC 60 NEGATIVE PULSES/SEC Rad Physics Prof. Stelmark

25 Rad Physics Prof. Stelmark
60 POSITIVE PULSES 60 NEGATIVE PULSES 120 PULSES 60 FULL CYCLES Rad Physics Prof. Stelmark

26 BATTERY – CURRENT OUTPUT
STEADY D/C Rad Physics Prof. Stelmark

27 D/C HALF WAVE RECTIFIED
D/C HALF-WAVE – 60 POSITIVE PULSES/SEC NEGATIVE PULSES ARE SUPPRESSED 1 PULSE/CYCLE Rad Physics Prof. Stelmark

28 D/C FULL WAVE RECTIFIED
D/C HALF-WAVE – 120 POSITIVE PULSES/SEC 2 PULSES/CYCLE Rad Physics Prof. Stelmark

29 D/C -3 PHASE 6 PULSE CURRENT
D/C 3 PHASE 6 PULSE – 6 PULSES/CYCLE Rad Physics Prof. Stelmark

30 D/C - 3 PHASE 12 PULSE D/C 3 PHASE 12 PULSE – 12 PULSES/CYCLE
Rad Physics Prof. Stelmark

31 DIODES OR VALVE TUBES HELP RECTIFY A/C CURRENT
ELECTRONS DIODE VALVE TUBE Rad Physics Prof. Stelmark

32 Rad Physics Prof. Stelmark

33 X-RAY TUBE FORWARD BIAS
Rad Physics Prof. Stelmark

34 Rad Physics Prof. Stelmark
REVERSE BIAS + - NO X-RAY Rad Physics Prof. Stelmark

35 Rad Physics Prof. Stelmark
FORWARD vs REVERSE Rad Physics Prof. Stelmark

36 Rad Physics Prof. Stelmark
RECTIFICATION TYPES HALF-WAVE FULL WAVE THREE PHASE SIX PULSE THREE PHASE TWELVE PULSE HIGH FREQUENCY SINGLE PHASE Rad Physics Prof. Stelmark

37 Rad Physics Prof. Stelmark
RECTIFICATION NO RECTIFICATION HALF-WAVE FULL-WAVE Rad Physics Prof. Stelmark

38 Rad Physics Prof. Stelmark
3 PHASE RECTIFICATION Rad Physics Prof. Stelmark

39 Rad Physics Prof. Stelmark
3 PHASE RECTIFICATION Rad Physics Prof. Stelmark

40 HIGH FREQUENCY RECTIFICATION
Rad Physics Prof. Stelmark

41 HALF-WAVE RECTIFICATION
Rad Physics Prof. Stelmark

42 HALF-WAVE RECTIFICATION
Rad Physics Prof. Stelmark

43 FULL-WAVE RECTIFICATION
Rad Physics Prof. Stelmark

44 FULL-WAVE RECTIFICATION
Rad Physics Prof. Stelmark

45 FULL-WAVE RECTIFICATION
Rad Physics Prof. Stelmark

46 Rad Physics Prof. Stelmark
3 PHASE 6 PULSE Rad Physics Prof. Stelmark

47 Rad Physics Prof. Stelmark
3 PHASE 12 PULSE Rad Physics Prof. Stelmark

48 Rad Physics Prof. Stelmark
HIGH FREQUENCY Rad Physics Prof. Stelmark

49 Rad Physics Prof. Stelmark
VOLTAGE RIPPLE HALF WAVE % FULL WAVE % 3 PHASE 6 PULSE % 3 PHASE 12 PULSE % HIGH FREQUENCY <1% Rad Physics Prof. Stelmark

50 Rad Physics Prof. Stelmark
RIPPLE 100% 100% 100% Rad Physics Prof. Stelmark

51 Rad Physics Prof. Stelmark
RIPPLE-3 PHASE 13% Rad Physics Prof. Stelmark

52 RIPPLE-HIGH FREQUENCY
<1% Rad Physics Prof. Stelmark

53 Home-made x-ray apparatus
Rad Physics Prof. Stelmark

54 CHECKING FAILURE OF RECTIFICATION SYSTEM
SPINNING TOP TEST – 1 PHASE EQUIPMENT SYNCHRONOUS SPINNING TOP TEST- 3 PHASE WITH LONGER EXPOSURE TIMES OSCILLOSCOPE- 3 PHASE EQUIPMENT WITH SHORT EXPOSURE TIMES Rad Physics Prof. Stelmark

55 Rad Physics Prof. Stelmark
SPINNING TOP TEST Rad Physics Prof. Stelmark

56 Rad Physics Prof. Stelmark

57 RESULT OF SPINNING TOP TEST- 1 PHASE - DASHES
Rad Physics Prof. Stelmark

58 HALF- WAVE RECTIFICATION
# OF DASHES = TIME (SEC) x 60 PULSES Rad Physics Prof. Stelmark

59 FULL- WAVE RECTIFICATION
# OF DASHES = TIME (SEC) x 120 PULSES Rad Physics Prof. Stelmark

60 RESULT OF SYNCHRONOUS SPINNING TOP TEST-3PHASE ARC
Rad Physics Prof. Stelmark

61 3 PHASE RECTIFICATION- LONGER EXPOSURE TIME
DEG. OF ARC = 360°/ sec x TIME (sec) Rad Physics Prof. Stelmark

62 UTILIZING OSCILLOSCOPE
Rad Physics Prof. Stelmark

63 UTILIZING OSCILLOSCOPE RECTIFIED SYSTEM
Rad Physics Prof. Stelmark

64 Rad Physics Prof. Stelmark

65 Rad Physics Prof. Stelmark

66 Rad Physics Prof. Stelmark
Main breaker - this is where the alternating current comes from to power the circuit. 2. Exposure switch - when you push the button to start an exposure this switch closes to start the exposure. 3. Autotransformer - this is where you adjust the kVp for the exposure. 4. Timer circuit - this part of the circuit stops the exposure. 5. High-voltage step-up transformer - this transformer bumps the voltage up so that the x-ray tube has very high voltage to make the electrons have enough energy to form x-rays. 6. Four-diode rectification circuit - this makes the current only go in one direction through the x-ray tube. 7. Filament circuit variable resistor - this variable resistor adjusts the current going to the filament. 8. Filament step-down transformer - this transformer steps the voltage down and therefore the current up.  9. X-ray tube - this is where the x-rays are created. 10. Rotor stator - this rotates the anode. Rad Physics Prof. Stelmark

67 Rad Physics Prof. Stelmark

68 Rad Physics Prof. Stelmark

69 Electrical Device and Location in Circuit
Control Factor Electrical Device and Location in Circuit kVp Selection kVp Level Autotransformer (between incoming line and exposure switch) mA Selection Filament Current Variable resistor (in filament circuit between incoming line and step-down transformer) Time Selection Length of exposure Timer circuit (between exposure switch and step-up transformer) Rotor Switch Speed of rotating anode Stator (separate circuit from stator of anode motor) Exposure Switch Moment of exposure Switch (between autotransformer and timer circuit) Rad Physics Prof. Stelmark

70 Rad Physics Prof. Stelmark


Download ppt "Rad Physics Prof. Stelmark"

Similar presentations


Ads by Google