Intermediate frequency furnace maintenance: thyristor medium frequency electric furnace shock treatment method 1: The intermediate frequency furnace can not be started, only the DC current meter has indication when starting, and the DC voltage and intermediate frequency voltmeter have no indication.
Inverter trigger pulse phenomenon, use the oscilloscope to check the inverter pulse (check on the thyristor AK), if there is a lack of pulse phenomenon, check whether the connection is not well contacted or open circuit, whether there is pulse output in the front stage.
The capacitor is broken down and the damaged capacitor pole is removed.
The load has a short circuit, grounding phenomenon, and the short circuit point and grounding point are eliminated.
The IF signal sampling loop has an open or short circuit phenomenon. Use an oscilloscope to observe the waveform of each signal sampling point and find the open or short circuit point.
Medium frequency furnace maintenance: thyristor medium frequency electric furnace shock treatment method 2: When the heavy load cold furnace starts, the electrical parameters and sounds are normal but the power is not up to overcurrent protection.
Analysis and processing:
The inverse transform flow angle is too small. Use an oscilloscope to view the commutation angle of the inverter thyristor, and adjust the commutation angle to an appropriate value;
The insulation resistance of the furnace body is low or short-circuited, and the resistance value of the furnace body is detected by a megger to eliminate the short-circuit point of the furnace body;
The resistance of the furnace steel relative to the induction coil is low, and the resistance of the furnace relative to the induction coil is detected by a megohmmeter; if the resistance is low, the furnace is rebuilt.
The furnace switch has a grounding phenomenon or the switch contacts have poor contact, and the furnace switch or contact is replaced.
Medium frequency furnace maintenance: thyristor medium frequency electric furnace shock treatment method 3: starting difficulty, the maximum DC voltage can only rise to 1400v after starting, and the reactor vibration is large, the sound is dull.
Rectifier thyristor open circuit, breakdown, soft breakdown or electrical parameter performance degradation, use an oscilloscope to observe the voltage drop waveform of each rectifier thyristor, find the damaged thyristor and replace it.
A set of rectification trigger pulses is missing. Each oscilloscope is used to check each trigger pulse. When a loop without a pulse is detected, the fault location is determined by the reverse push method, and the damaged device is replaced.
