TIMER Russian patent published in 2001 - IPC

FIELD: on/off switching of final elements in automatic-control devices. SUBSTANCE: timer has three-contact relay and time meter; metering input of the latter is connected to first pole of power supply, common lead, to second pole through on/off contacts of relay, and output, to first lead of relay coil whose second lead is connected to second pole of power supply through additional turn-on control circuit set up of series-connected threshold element, rectifier, and first ballast resistor; rectifier inputs are connected between fixed on/off contacts of relay through second ballast resistor; metering input of time meter is connected between second ballast resistor and first pole of power supply through heater and end-of-thawing sensor; common lead of time meter is connected to first pole of power supply through compressor. Timer is designed for long-time trouble-free operation at low power requirement. EFFECT: improved performance characteristics, enhanced economic efficiency and service life of device under control. 1 dwg