Electronic circuit for the detection and analysis of normal zones in a superconducting coil

In an electronic circuit for the detection and analysis of normal zones in a superconducting coil, the combination of:

• a balanced bridge circuit electrically coupled to a superconducting coil and producing an output voltage signal proportional to the inductance and series resistance of the coil;
• means coupled to the bridge circuit to receive the output voltage signal and to multiply it by a signal representing current in the superconducting coil, the resultant signal representing the real power being dissipated in the superconducting coil;
• means coupled to the multiplying means to receive the signal representing the power being dissipated in the superconducting coil and to subtract from said signal a signal representing the background power loss in the superconducting coil, and then to integrate the difference signal with respect to time to generate a signal on an output lead representing the energy being dissipated within the superconducting coil;
• means coupled to said integrating means to receive the signal representing the energy being dissipated within the superconducting coil and to compare it against a signal representing a critical energy reference and to provide a quench signal when the critical energy reference is exceeded;
• and
• means connected to the comparing means to receive a quench signal, to disconnect the superconducting coil from its power source and permit dissipation of the stored energy into an external device.