- 18
- Oct
About induction melting furnace main protected content, set causes and methods
Biz haqimizda induktsiya eritish pechkasi main protected content, set causes and methods
Protected name | Protection reason and protection method |
The cooling water temperature is too high | When the outlet temperature of the cooling water exceeds the specified allowable value, it is easy to cause scale, or even vaporize the water, causing an accident. Therefore, a charged water temperature gauge can be installed at the outlet of each water-cooling pipeline. When the water temperature at the exit of any cooling water circuit exceeds the allowable value, an alarm signal will be issued |
Cooling water pressure drops | When the water pressure of the cooling water is lower than the required number, the cooling conditions will be destroyed. On the main cooling water inlet pipe, there is a water pressure gauge with a live contact. When the water pressure drops below the allowable value, an alarm signal is issued and the sensor power supply circuit is cut off |
Over current, short circuit protection | Install a differential protection over-current relay, when the main circuit has an over-current and short-circuit accident, the main circuit is cut off and an alarm signal is issued |
Voltdan himoya ostida | In front of the main circuit closing contactor, an undervoltage relay is connected. When the main circuit is de-energized, the main circuit closing contactor will automatically trip, and there will be an accident signal indication. When the next call comes, reclose |
Phase C open phase protection | At the outlet end of the balancing device, there is a C- phase open-phase protection relay. When phase C is cut off, the main circuit is immediately cut off, and there is a signal indication to prevent resonant current in the balance reactance and balance capacitor circuit, which will burn out the balance reactor and capacitor |
Protected name | Protection reason and protection method |
Limit the protection of the main circuit closing current | In the induction furnace, there are a large number of compensation capacitors and balancing capacitors, which will generate a large inrush current when closing. Therefore, the main circuit is closed twice. First close the starting contactor with resistance, then close the working contactor, and cut off the resistance |
Transformer oil temperature indication and gas protection | The electric furnace transformer has an oil temperature indicator to monitor the oil temperature. Gas protection is also installed on the larger capacity electric furnace transformer ( above 800KVA ). When a fault occurs and the Buchholz relay will act, the power supply circuit will be cut off and an alarm signal will be issued |
Capacitor internal overcurrent protection | Phase-shift capacitors and intermediate-frequency electric heating capacitors below 3000V power frequency are all connected with over-current fuse protection inside. When any group of capacitors fails, the group will be automatically cut off. |
Crucible leakage furnace and main circuit grounding protection | Equipped with crucible alarm device. When the crucible leaks out of the furnace or the main circuit is grounded, the power is cut off and an alarm signal is issued |
Haddan tashqari kuchlanishdan himoya qilish | Install an over-voltage absorber on the secondary side of the transformer to prevent operating over-voltage, transformer primary and secondary side breakdown and over-voltage caused by lightning strikes |
Capacitor discharge protection | After the main circuit is powered off, the capacitor must be discharged for safety. The capacitor is automatically discharged through the load, and the variable capacitor is automatically placed in the resistance circuit for discharge |