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VARS – The Vange Amateur Radio Society
A presentation by: Steve, G0KVZ
30th July 2009
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VARS – The Vange Amateur Radio Society
• Early power generation and distribution was using d.c.• See: http://en.wikipedia.org/wiki/War_of_Currents
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VARS – The Vange Amateur Radio Society
P = I R2
• The distribution of power at low voltages leads to large losses
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VARS – The Vange Amateur Radio Society
time
Am
plit
ude
• Scientists started to experiment with a.c. electricity
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VARS – The Vange Amateur Radio Society
• The price of copper makes large gauge cables costly• Large gauge cables would require substantial pylons
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VARS – The Vange Amateur Radio Society
• a.c. generation and distribution soon established the transformer
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VARS – The Vange Amateur Radio Society
Left hand rule - Motors Right hand rule - Generators
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VARS – The Vange Amateur Radio Society
?
• A number of variations, but two basic types of device
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VARS – The Vange Amateur Radio Society
• Simple bobbins are easiest to wind
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VARS – The Vange Amateur Radio Society
VideoOfLinearWinding
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VARS – The Vange Amateur Radio Society
Fly winding techniques
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VARS – The Vange Amateur Radio Society
Whiteboard description
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VARS – The Vange Amateur Radio Society
• Standard transformers need the core to be applied after winding
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VARS – The Vange Amateur Radio Society
VideoOfLaminating Machine
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VARS – The Vange Amateur Radio Society
• Ferrite is an alternative core material
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VARS – The Vange Amateur Radio Society
“C” Core transformers
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VARS – The Vange Amateur Radio Society
• Each pass through the centre of the core counts as one turn
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VARS – The Vange Amateur Radio Society
Magnetic flux
Leakage flux
SecondaryWinding
PrimaryWinding
SecondaryWinding
Negligible leakageflux due to lack ofgaps in torus.
• Similarities and differences
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VARS – The Vange Amateur Radio Society
• Toroids often require more work in terminating & finishing
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VARS – The Vange Amateur Radio Society
VideoOfToroidalWinding
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VARS – The Vange Amateur Radio Society
VideoOfToroidal insulation machine
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VARS – The Vange Amateur Radio Society
Advantages of Toroidal designs
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VARS – The Vange Amateur Radio Society
• All types of transformer require environmental protection
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VARS – The Vange Amateur Radio Society
• Some examples of different construction styles
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VARS – The Vange Amateur Radio Society
VideoOfSpring winding
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VARS – The Vange Amateur Radio Society
Design considerations
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VARS – The Vange Amateur Radio Society
configuration
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VARS – The Vange Amateur Radio Society
Modification
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VARS – The Vange Amateur Radio Society
