21 10 2010

All photos.

I have put the superconducting magnet into a persistent state!!!!!

Power supplies off, magnet still going!

Details to follow.


OK. Here it is. The units are in raw volts coming from the magnetometer and the current sensing resistor (0.008 ohms). The red is the current going into the superconducting coil, the white is the magnetic field. You can see that the current drops off, but the magnetic field persists. WIN!!!!

The magnetic field gradually falls off over the course of an hour.

This is the setup:

SC coil in the dewar:

Here is the schematic:

It was all controlled manually by switching the power supplies on and off.

Superconducting Magnet Test 3

21 10 2010

All photos.

I re-spooled the YBCO on it’s original spool. Hoping for a stronger magnet and less liquid nitrogen.

We ran 2A DC through the coil at room temperature and David searched for the strongest point of the field.

Which turned out to be the very center, perhaps amplified by the ferrous steel screw:

In this configuration we are seeing ~140 gauss magnetic field while running 5A DC current through the SC magnet submerged in liquid nitrogen (with no persistent switch short circuit):

Much better!

Next we re-fabricated the persistent switch… this time using a much longer splice, better soldering, and a longer heater directly over the splice:

We also included some heat shrink tubing to insulate the heater:

We will test this again today!

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