Shotky
Newbie level 4
Hello everyone!
I am trying to obtain the phase relation between the output voltage of a pick up coil (wound coil of 150 turns), when inserted into a variable magnetic field, and the filed excitation current.
This field is obtained from an alternating excitation current that flows into a wire loop, the pick up coil is placed at the center of this current loop.
The excitation current is obtained from a KEPCO 72-6m power supply/amplifier, used in current mode and controlled with a sinusoidal waveform at fixed amplitude and with frequency in the range 100Hz- 100kHz, obtained from a waveform generator.
Current excitation and coil output voltage signals are acquired with a DAQ board; the coil is connected to the DAQ analog input in floating source configuration with a 20 m long twisted pair cable, the excitation current is obatained from the voltage drop on a shunt resistor (50m ohm).
what I obtain is in the attached files: the difference between coil voltage phase and excitation current phase is not in a range of 180 degrees, anche it seems that the peak resonance in the amplitude plot ( ration of V amplitude anche I amplitude) is not at the same frequency of the resonance in phase plot.
Can someone please help me understand what I am doing wrong?
I am trying to obtain the phase relation between the output voltage of a pick up coil (wound coil of 150 turns), when inserted into a variable magnetic field, and the filed excitation current.
This field is obtained from an alternating excitation current that flows into a wire loop, the pick up coil is placed at the center of this current loop.
The excitation current is obtained from a KEPCO 72-6m power supply/amplifier, used in current mode and controlled with a sinusoidal waveform at fixed amplitude and with frequency in the range 100Hz- 100kHz, obtained from a waveform generator.
Current excitation and coil output voltage signals are acquired with a DAQ board; the coil is connected to the DAQ analog input in floating source configuration with a 20 m long twisted pair cable, the excitation current is obatained from the voltage drop on a shunt resistor (50m ohm).
what I obtain is in the attached files: the difference between coil voltage phase and excitation current phase is not in a range of 180 degrees, anche it seems that the peak resonance in the amplitude plot ( ration of V amplitude anche I amplitude) is not at the same frequency of the resonance in phase plot.
Can someone please help me understand what I am doing wrong?