Formula for new number of turns whit new power
Formula for new number of turns whit new power
(OP)
Hello,
Some of you may be familiar whit the formula for calculating the new numbers of turns when the voltage or the frequency change
ns*u2/u1*f1/f2=ns2
ns = numbers of turns (start)
u2 = new voltage
u1 = voltage
f1 = Frequency
f2 = New Frequency.
But do anyone here knows he formula if you also want to concider to change the power.
I know that for exampel if you decrease the power the new number of turns must increase.
I have a application, but i dont have the formula.
Please share :)
Best regards
Some of you may be familiar whit the formula for calculating the new numbers of turns when the voltage or the frequency change
ns*u2/u1*f1/f2=ns2
ns = numbers of turns (start)
u2 = new voltage
u1 = voltage
f1 = Frequency
f2 = New Frequency.
But do anyone here knows he formula if you also want to concider to change the power.
I know that for exampel if you decrease the power the new number of turns must increase.
I have a application, but i dont have the formula.
Please share :)
Best regards





RE: Formula for new number of turns whit new power
RE: Formula for new number of turns whit new power
Do you think you can put it in a formula ?
RE: Formula for new number of turns whit new power
If you want to keep flux density constant, the keep the quantity u/(n*f) constant.
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(2B)+(2B)' ?
RE: Formula for new number of turns whit new power
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(2B)+(2B)' ?
RE: Formula for new number of turns whit new power
Say you have a motor winded for 400 D 50 Hz rated 75kW whit 20 turns, if i want to make a new winding for 360 D 50 Hz whit the same power, then i need to take 20 * 360/400 = 18 Turns, 18 turns will my new winding have to fit the new voltage.
But i cant figure out how to calculate the new numbers of turns if the power also change.
RE: Formula for new number of turns whit new power
There are a few things you can do to achieve incremental increases in power.
1> Raise the voltage. If you drop the voltage the power will drop.
2> If there is space, wind the motor with heavier gauge wire to allow more current with the same heat developed.
3> Wind the motor with a higher temperature rated wire so the current can be increased and the motor allowed to run hotter.
4> Add more cooling.
Be aware that the more load is applied to a motor, the further back on the speed/torque curve it will operate and the more slip there will be.
There is a limit to the magnetic field strength. Motors are designed to run close to magnetic saturation. This is a characteristic of the stator and rotor iron and can't be changed by changing the windings. You can't use much more than 110% of rated voltage before saturation becomes an issue.
You may use a VFD and run the motor at a higher voltage and frequency. At double voltage and double frequency you have double the HP.
Bill
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"Why not the best?"
Jimmy Carter