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Energy Removal from a Superconducting Solenoid

IP.com Disclosure Number: IPCOM000095529D
Original Publication Date: 1964-Feb-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

Dowley, MW: AUTHOR

Abstract

An oscillatory circuit absorbs the energy in a superconducting solenoid 11 in a cryostat 12. Such occurs in the event the material of the solenoid undergoes a transition to the resistive state. Superconducting solenoid 11 has a closely coupled secondary coil 1 la. This is connected to a resistor 18 disposed externally of the cryostat. An oscillatory circuit including a capacitor 13 and a diode 14 connects to solenoid 1 1 but is maintained normally bypassed by contacts 16a of fast-acting relay 16. Relay 16 is actuated by detecting device 17 including a current transformer which detects a decrease in the current in winding 11 at the onset of resistivity and operates to actuate relay 16. This, when actuated, opens contacts 16a and connects capacitor 13 and diode 14 in circuit with solenoid 11.

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Energy Removal from a Superconducting Solenoid

An oscillatory circuit absorbs the energy in a superconducting solenoid 11 in a cryostat 12. Such occurs in the event the material of the solenoid undergoes a transition to the resistive state. Superconducting solenoid 11 has a closely coupled secondary coil 1 la. This is connected to a resistor 18 disposed externally of the cryostat. An oscillatory circuit including a capacitor 13 and a diode 14 connects to solenoid 1 1 but is maintained normally bypassed by contacts 16a of fast-acting relay 16.

Relay 16 is actuated by detecting device 17 including a current transformer which detects a decrease in the current in winding 11 at the onset of resistivity and operates to actuate relay 16. This, when actuated, opens contacts 16a and connects capacitor 13 and diode 14 in circuit with solenoid 11.

The current in winding 11 tends to oscillate into capacitor 13.

The resulting flux change in secondary 11a causes a current to flow in the secondary circuit including resistor 18. If the quantity >pi (LC)/1/2//2|/2, the time constant of the primary alone, is much less than L/R(2) (where R(2) is the resistance of resistor 18), the time constant of the secondary alone, then the decay of current in the primary is given by I = I(0) Cost omega t approximately. Here omega = >LC(1-k2/2/| - 1/2 and k is the coupling constant between solenoid 11 and secondary 11a. Thus, there is a decay of current to zero in a time equal to (pi >LC(1...