- #1
chitrageetam
- 16
- 0
Hi..
I have a question about AC magnetic field, wondering if you can help me understand this.
For a DC solenoid coil, We can say Magnetic field H=N*i/L (simplest form)
For an AC input, H=N*isin(wt)/L ; H(rms) = N*i/L (i is RMS value)
As long as the current i-rms is kept constant, the solenoid must produce the same magnetic
field at any frequency. But,in my measurements, even if I keep the current constant, the field
is still dropping as the frequency is increased (from 100 Hz to 10kHz).
I wonder why the field decreases..
I understand that apparent power increases because of the inductance, eddy current etc..
Does the field really reduce with frequency?
I wonder if there is any different formula to estimate the field at high frequency.
Thanks
Chitra
I have a question about AC magnetic field, wondering if you can help me understand this.
For a DC solenoid coil, We can say Magnetic field H=N*i/L (simplest form)
For an AC input, H=N*isin(wt)/L ; H(rms) = N*i/L (i is RMS value)
As long as the current i-rms is kept constant, the solenoid must produce the same magnetic
field at any frequency. But,in my measurements, even if I keep the current constant, the field
is still dropping as the frequency is increased (from 100 Hz to 10kHz).
I wonder why the field decreases..
I understand that apparent power increases because of the inductance, eddy current etc..
Does the field really reduce with frequency?
I wonder if there is any different formula to estimate the field at high frequency.
Thanks
Chitra