Jumping Rings (Eddy Currents)

video embedded
Type of activity: demo
Activity code:  M-002b

Description:

Avoid using more than 80VAC with the variac, as the variac fuse may blow. Current in the coil varies from 4A to 10A at 80VAC depending on the position of the core. The coil is rated for 110 V A.C.

Please do not remove the core when there is current in the coils.

Turn on Variac and observe the solid copper or aluminum ring levitate /  jump off the metal core. Place split copper ring on the core and observe that it remains at rest.

Options:
Liquid N2 for cooling the Al ring
plastic ring

 

Historic Diagram:

 

Video:

source: https://play.library.utoronto.ca/1d3c68a94fafd555584ce3ee096e34b7

Apparatus

Variac
Variac
Cenco Induction Coil
ugdemos says:
Apr 26, 2013 08:14 PM
April 4th, 2013 Piero Triverio
2:15pm pickup ECE 259

**refer to issue tracker**
ugdemos says:
Apr 26, 2013 08:14 PM
April 3rd, 2013 Costas Sarris
10:15am ECE259 pickup
ugdemos says:
Apr 26, 2013 08:26 PM
April 3rd, 2013 Micah Stickel
1pm ECE221

*Note: with LN2
ugdemos says:
Apr 26, 2013 08:27 PM
April 2nd, 2013 Micah Stickel
11:30am ECE221 pickup

*Note: with LN2
ugdemos says:
Apr 26, 2013 08:27 PM
April 1st, 2013 Andrew Meyertholen
9am, 11am-12pm PHY132 CH
4pm, 5pm-6pm PHY132 MP102

*Note: with LN2
ugdemos says:
Aug 08, 2013 09:09 PM
March 27, 2013 Andrew Meyertholen
11am-12pm PHY131 CH
5-6pm PHY131 MP102