METHOD FOR CONTROLLING SINGLE-PHASE INDUCTION ASSEMBLY FOR SOLDERING OF LOW-DIAMETER PIPELINES Russian patent published in 2000 - IPC

FIELD: electrical engineering, gas and oil industry. SUBSTANCE: method may be used for laying of low-diameter pipes, which diameter is less than 160 mm. Method is applicable to low phase angle values, which measurement is complicated and which are characteristic for inductive soldering of low-diameter pipelines, i.e. dynamic active load with low time lag. Control method involves measurement of instantaneous values of current and voltage levels, generation of first electric signal, which is proportional to difference between number of measurements which lead to zero current and zero voltage levels in interval of 40-50 m sec with frequency within range of 1-2*120 microseconds. Then, method involves generation of second and third electric signals as ratios of measured current and voltage levels using stored current and voltage levels before zero values, to sum of current and voltage levels immediately before and after zero values. Then, method involves generation of control signal and switching capacitance of capacitor battery of induction assembly after comparison to given value. Operations for measurement of current and voltage levels is repeated in cycles of 40-50 m sec. This results in possibility to reach desired quality of laying of low-diameter pipelines and to decrease unnecessary power consumption. EFFECT: simplified and facilitated measurement of phase angle, increased speed and precision of induction assembly control. 2 dwg