Intermediate frequency furnace common failure

Intermediate frequency furnace equipment common failure and analysis

1. Failure phenomenon: the medium frequency furnace equipment runs normally, but from time to time sharp beeps can be heard, and the dc voltmeter has a slight swing.

Analysis: use oscilloscope to observe the inverter dc voltage waveform at the ends of the bridge, a frequency failure or indefinite cycle short, parallel resonant inverter circuit transient failures can be recovery since the periodic short, failure is generally inverter control part by rectifying the pulse interference, aperiodic transient failure is usually produced by intermediate frequency transformer turn-to-turn insulation bad.

2. Fault phenomenon: abnormal sound appears after the device has been running for a period of time, and the meter reading shakes the device.

Analysis and treatment: after the equipment has been working for a period of time, abnormal acoustic work is unstable, mainly due to the poor thermal characteristics of the electrical components at work, the electrical part of the equipment can be divided into weak and strong parts, respectively detected. First detect the control part, can prevent damage to the main circuit power device, in the case of the main power switch, only connected to the control part of the power supply, after the control part works for a period of time, with an oscilloscope to detect the trigger pulse of the control panel, to see whether the trigger pulse is normal.

On the premise that there is no problem in the control part, open the equipment. After the abnormal phenomenon occurs, observe the tube pressure drop waveform of each thyristor with an oscilloscope to find out the thyristor with poor thermal characteristics. If the thyristor tube voltage drop waveform is normal, it is necessary to pay attention to whether there is a problem with other electrical components, especially circuit breakers, capacitors, reactors, copper line contacts and the main transformer.

3. Fault phenomenon: the equipment works normally but the power cannot go up

Analysis and treatment: the normal operation of the equipment can only mean that the parts are in good condition, the power cannot go up, and the adjustment of the equipment parameters is not appropriate. The main reasons affecting the power failure of the equipment are as follows:

(1) the rectifying part is not adjusted properly, the rectifier tube is not fully conducted, and the dc voltage does not reach the rated value, which affects the power output;

(2) if the voltage is adjusted too high/too low, the power output will be affected;

(3) the power output is low due to improper adjustment of cut-off pressure;

(4) the mismatch between the furnace body and the power supply seriously affects the power output;

(5) too much or too little compensation capacitor configuration can not get electrical efficiency and thermal efficiency reliable power output, that is, not reliable economic power output;

(6) the distributed inductance of output circuit and the additional inductance of resonance circuit are too large, which also affect the maximum power output.