Power Input of 50hz vs 60hz? 1

[Oroni]

I am designing a coil for 120V 60hz, resistance is 1500 ohm, with 9.6 watts of input power. My question is what will happen when 220V 50hz is applied to the same coil?

 

[debodine]

Ignoring the inductive reactance of the coil (since you do not list the inductance or the reactance). your setup at 120V will allow a current flow of 80mA. Effectively doubling the voltage (nearly, anyway) to 220V will cause nearly double the current flow (actually about 147mA), and will nearly quadruple the power consumed (to about 32W), assuming that your power source can deliver that much additional power. (E / R = I; I^2 * R = W)

Therefore your input circuit would need to be able to handle almost twice the current and dissapate four times as much heat at 220V as it would at 120V.

All of this neglects the effects of reactance. Any reactance, (and a coil will have some value of reactance) will cause a shift in power factor which will increase the amount of volt-amperes necessary at the input to accomplish the same amount of work at the load.

 

[Oroni]

This brings up another question.
By keeping the same amount of work at the load, I need a different coil winding increasing the resistance to approximately 5042 ohms at 220V, 50hz, maintaining the 9.6 watts. But, I will still have a shift in power due to the reactance of the coil, so will the resistance of 5042 ohms still need to be increased?

 

[itsmoked]

By all means.

You realize that almost all your coil "resistance" is provided by its inductance?

The inductance normally increases by a huge amount once the slug is pulled in. Are you pulling in some sort of slug?

 

[SolderingGunslinger]

the formula for inductive reactance (X sub L) is 2*pi*F*L so L in henrys is L/2*PI*F

Your inductance is 3.980892 Henrys

XsubL for 50 Hz is 1250 Ohms.

This doesn't take into effect any DC resistance in the coil.

I remain,

The Old Soldering Gunslinger

 

[stargate3216]

You'd probably burn out the coil.