[Chou, Yeh, Ohashi, Iida, Ki, Chang, and Washimi]
Today we made a large coil (2m x 6m, N=96) for the magnetic injection. It takes about 2 hours (13:50 - 16:00).
We also measured the electrical properties of this coil:
| Design | Measured | |
| Resistance @ DC | 8.3 Ω | 8.4 Ω |
| Inductance @ 1kHz | 112 mH | 111 mH |
[Chou, Yeh, Ohashi, Iida, Ki, Chang, and Washimi]
Today we tested the large coil with a small amplifier (as a coil driver) and an oscilloscope (a function generator is built-in).
We generated sine waves with 100mV amplitude and 20-1000Hz frequencies, by the FG.
At first, we measured the transfer function from the FG voltage signal to the output of the amplifier (Fig.3), with the large coil connected.
From this TF, we calculated the applied current on the coil. (Fig.4)
We confirmed it was less than 0.1 A.
Next, we measured the TF from the amplifier output voltage to the magnetometer signal voltage (Fig.5), by locating the magnetometer at the center of the coil, z=112cm height.
From this result, we calculated the TF from the current to the magnetic field. (Fig.6)
We also performed the same TF measurements by locating the magnetometer at varied places. (to be reported future)
When the current amplitude is 0.06A, the power consumption as heat is calculated to be
P = R * I_RMS^2 = 8.4Ω * (0.06A *√2)^2 = 0.06 W.
During today's work, I checked the temperature with a thermography.
A significant temperature increasing was not found.
sorry, my calculation from amplitude to RMS was wrong. The correct way is
P = R * I_RMS^2 = 8.4Ω * (0.06A /√2)^2 = 0.015 W.
[Kobayashi, Diego, Yu, and Washimi]
Today we measured the transfer functions from the large coil current to the magnetic field (Bx, Bz), along the X-axis through the center of the coil, at 1m height.
This result will be compared with a simulation in the future.
After the StudentWorkshop, we put the large coil on the shelves and fixed with cable-ties for preventing falls and trips
I updated the analysis for the TF(coil -> Magnetometer) measurements. The changed points are:
I also compared the measured data with my simulation. In this simulation, I only used the measured geometry, R[Ω], L[mH], and N.
The result shows a good agreement without any fine-tuning.
