The Shop > Electronics & IC Programing
Magnetic flux
Bluechip:
--- Quote from: Noitoen on June 09, 2013, 12:51:02 PM ---For motor windings, the number of turns is related to the voltage and the thickness of the wire, the current. So you have to count the number of turns to wind the same amount. Since on a motor, higher resistance of wire will result in efficiency loss due to heat, the thicker the wire, the better. When they design a motor's slot to take aluminium to save on cost, they have to make more room for the wire in relation to copper. If you want, you can use the same diameter copper wire.
--- End quote ---
Not sure about that. If the Al. is replaced by the same number of turns and the same gauge in copper, the resistance will be much lower. Current will increase. ??
Dave BC
Noitoen:
No, the current will not increase. The current is "regulated" by the core and the back EMF generated by the moving rotor. If you measure the resistance of an ac circuit, being it a motor or transformer and try to calculate current with ohm's law, you will see that it doesn't ad up. What works here is the Z in ohms which is related to the inductance in Henry and frequency in Hz. The inductance is related to the size of the magnetic core and number of turns.
If you power up a transformer coil without the core, it will burn in seconds due to over current.
Bluechip:
Still not convinced. That winding is a series L/R circuit. If you change R Then the phase angle will change as will the Z vector. If the impedance changes, so will the current.
It can do no other.
Too late in the day for me to fool about with vector diagrams though ... :)
Early start tomorrow .. :(
Dvae BC
awemawson:
It's the overall impedance of the windings that counts regarding current flow. ie the R plus the Z. In the case of an aluminium winding compared to a copper one the difference in R will be so small as to be insignificant compared to the Z component unless it's a very odd generator.
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