THYRISTOR REGULATOR OF TEMPERATURE OF ELECTRIC HEATER Russian patent published in 1997 - IPC

FIELD: electrical engineering, electric heaters based on thyristors, temperature-sensitive resistors and electronic control means using alternating current. SUBSTANCE: provision for high accuracy of control, stability, reliability and efficiency of regulator, prolonged service life and reduced dimensions are achieved by use for temperature control of balanced bridge with temperature-sensitive resistor in one of arms and null detector acting on control of thyristor placed in diagonal. Thyristor is connected in series with electric heater to A.C. network feeding bridge circuit. Circuit provides for optimal time delay of initiating pulses with reference to beginning of half-periods of network. Thyristor is initiated at time moments when anode voltage is already present across thyristor. This voltage is sufficient for its switching on but close to minimal one when du/dt, di/dt and commutation interference are minimal. EFFECT: increased stability, reliability and efficiency, prolonged service life and reduced dimensions. 2 dwg