Induction cooking appliance having improved protection circuits
US4010342A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 29, 1974 |
| Grant date | Mar 1, 1977 |
| Priority date | — |
| Expiry date | Oct 29, 1994 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H7/122
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An induction cooking appliance for heating a metallic utensil by means of an ultrasonic frequency magnetic field. The appliance includes a smooth, substantially non-metallic cooktop for supporting the utensil, and a work coil mounted below the cooktop for coupling the magnetic field to the utensil. The work coil is arranged in a solid state inverter circuit, including a gate controlled thyristor and a commutating capacitor, arranged to convert a d.c. voltage to current pulses of ultrasonic frequency. Simplified inverter protection circuits assure that conditions within the inverter do not exceed the component ratings. The protection circuits include a load sensing circuit for disabling the inverter when unloaded or when improperly loaded. An associated circuit responds to the power operating level of the inverter for varying the sensitivity of the load sensing circuit. Further protection is provided by an over-voltage limit circuit also adapted to disable the inverter. Means are provided for limiting potentially damaging voltage transients which may be generated when the inverter is disabled by the load sensing circuit. User convenience is enhanced by providing, in combination with…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.