Maintenance method for 3T steel shell melting furnace failure 2019
3T steel shell melting furnace is prone to failure during normal operation
The 3T steel shell melting furnace operates normally but burns out multiple KP thyristors and fast melts during normal overcurrent protection.
In order to analyze the energy of the smoothing reactor when the overcurrent protection is processed, the rectifier bridge is switched from the rectified state to the inverting state. If α=150 ̊, it may cause active.
The inverter subverts and burns multiple thyristors and fast-melting, and the switch trips, accompanied by a huge current short-circuit explosion sound, which generates large current and electromagnetic force shock to the transformer.
Pressure device.
The 3T steel shell melting furnace is operating normally, but the 3T steel shell melting furnace near the high voltage zone is unstable, the DC voltmeter is shaking, and the 3T steel shell melting furnace is accompanied by a squeaky sound.
The inverter bridge subverts and burns the thyristor.
It is more difficult to analyze and deal with such faults to eliminate high-pressure ignition of some components that occur in 3T steel shell melting furnace :
(1) The loose copper wire connector screw causes the fire;
(2) oxidation of the main joint of the circuit breaker causes ignition;
(3) The compensation capacitor wiring pile screw is loose, causing the internal ignition resistance of the ignition compensation capacitor to ignite the capacitor;
(4) The insulated part of the water-cooled radiator is too dirty or charred to the ground;
(5) Furnace induction coil to furnace shell furnace. The spacing of the induction coils of the base plate firing furnace is too close, and the insulating column of the induction coil of the furnace body is fired or arced to catch fire due to high temperature carbonization discharge.
The inside of the thyristor is ignited.
The 3T steel shell melting furnace is operating normally but can hear sharp humming sounds from time to time, while the DC voltmeter swings slightly.
Analysis and processing Observe the voltage waveform at both ends of the DC bridge of the inverter bridge with an oscilloscope. It can be seen that the inverter is cyclically short, one cycle fails or the period of the indefinite period fails briefly, and the parallel resonant inverter circuit is short.
The temporary failure can be self-recovery and the periodicity is short. The failure is generally that the inverter control part is interfered by the rectification pulse. The non-periodic short-term failure is generally caused by poor insulation between the intermediate frequency transformers.
