Equipment electrical maintenance knowledge

Medium frequency induction melting furnaces often use the following four configurations

Time: 2019-07-06

Each of the four configuration schemes has its own advantages and disadvantages. It is usually necessary to select the specific configuration method according to the casting process requirements of the equipment demand side, the on-site power conditions, the production target and the development scale to meet the requirements of efficient, safe and stable use of the equipment. Easy to flexibly adjust the process or scale expansion.

Option 1. Single power supply mode;

Scheme 2. Single power supply (series resonance) one-to-two method;

Scheme 3. Dual power supply (parallel resonance) dual power supply mode;

Scheme 4. Dual power supply mode for large power supply and small power supply + furnace switch;

Option 1: Single power supply mode:

Each set of electric furnace has one transformer and one set of single-supply intermediate frequency power supply system; each set of electric furnace adopts double furnace body, one for one, one single power supply

. When working: one furnace melts and the other furnace spares. The power of the independent intermediate frequency power system in each electric furnace is adjustable.

Option 2: Single power supply (series resonance) dual power supply mode:

Each set of electric furnace has a transformer and a series of resonant intermediate frequency power supply system. Each set of electric furnace adopts double furnace body. At the same time, the power supply mode, the double furnace body has simultaneous work, one furnace body melts and one furnace body heats up, heats up and tempers. Features.

During normal work: one furnace melts and the other heats up, keeps warm, and tempers. Each IF power system can be freely distributed between the two furnace shells.

Configuration Description: One transformer is used, and one series resonance (one to two) intermediate frequency power supply is allocated to the two furnaces on two electric furnaces.

The composition of the series resonant intermediate frequency power supply is: a set of rectifier cabinets ------ two sets of inverter cabinets ------- two sets of capacitor cabinets;

The main work features are: one melting, and the other insulation, continuous supply of molten iron or casting of large castings.

Its advantages: diode rectification, high power factor of 0.95, constant power output


1. At present, the high-power series resonance (one to two) IF power supply is still not mature in China and is not popularized.

It is also rare for manufacturers of domestically produced equipment to have outstanding performance.

2. The inverter of the series resonant intermediate frequency power supply adopts IGBT components, and the current capacity of the IGBT components cannot meet the stable operation of the high power power supply. Foreign companies such as the company's inverter with thyristor series resonant intermediate frequency power supply can increase the power supply. However, the domestic technology is not yet mature.

3. Single high-power power supply configuration. When the power supply fails, the whole set of equipment will not be able to be smelted, thus affecting production.

4. The cost of the equipment is high, and the domestic price is high.

5. The failure rate is high, the maintenance is difficult, the spare parts are not interchangeable, and the maintenance cost is high.

Option 3: Dual power supply (parallel resonance) dual power supply mode:

Dual power supply and dual furnace configuration + power splitter:

Not only can the system realize all the functions of “one to two electric furnaces”, but also one power supply can be operated when one power supply fails, thus avoiding affecting production. In the whole system, two furnaces in each set of electric furnace can work at the same time. When working: one furnace melts, and the other furnace heats up, heats and tempers. Configuration features: The set of electric furnace equipment uses a set of transformers for two independent intermediate frequency power systems.

Configuration instructions:

One transformer, two intermediate frequency power supplies, and two furnace bodies. The two furnaces work simultaneously through the power splitter. When working, one furnace melts and the other heats up.

Dual power supply dual power supply configuration

1 The two sets of independent intermediate frequency power supply in the set of electric furnaces are infinitely adjustable, and the power adjustment range is: 10~100%. Mainly to enable users to increase productivity and meet different production process needs. The heat preservation and heating sections can be accurately adjusted, and the two furnace bodies can simultaneously preheat and sinter the furnace lining, or one furnace body can be smelted and the other furnace body can be insulated. This maximizes production efficiency and reduces smelting costs.

2 Set on-site operation cabinet on the electric furnace platform to control the operation, stop and power output adjustment of the two sets of power supply. Output power adjustment is available for manual/automatic control. The operation cabinet can be installed with computer, display screen and instrument to display the power running status and fault status, and control two intermediate frequency power supplies with two furnace bodies working alone or at the same time. It can meet the requirements of one furnace body heat preservation and one furnace body melting, and the two furnace bodies simultaneously heat up work. When a furnace needs to be repaired when it fails, the other furnace can work normally.

3 computer system has smelting monitoring, setting alarm, data acquisition display, the system continuously monitors and displays various main parameters; can automatically diagnose and display system faults automatically, and can also remember the source of the trip; can monitor the incoming line voltage at any time; display : Power running status, power consumption (KW.h), voltage, current, power, furnace voltage, current, operating frequency and other parameters, as well as fault diagnosis status.

4 power distribution, limit function: turn on the power automatic control system, the two power supplies can freely switch the working state (melting / insulation), and can ensure that the total power of the two power supplies does not exceed the limit value.

5 Isolation device: When a furnace fails and needs to be repaired, the isolation device can disconnect two control systems and the other furnace can work normally.

Its advantages:

1. Single transformer + double intermediate frequency power supply can meet the requirements of any operation and production mode of the user, so that the power of the intermediate frequency power supply can be fully utilized, and the power of the transformer can reach the optimum value.

2. The dual intermediate frequency power supply configuration mode is stable and reliable. Even if one power supply fails, the other power supply can also be produced normally. Meet the requirements of large-scale continuous production.

3. It can avoid equipment failure caused by changing the furnace switch. It meets the user's overall requirements for equipment, and the equipment is durable, stable, safe and reliable.

4. When the user expands production, he only needs to increase the transformer capacity to double the output.

Disadvantages: high cost and slightly larger investment. (But the price is lower than the tandem (one to two) device.

The insulation power supply cannot be fully charged, so the power factor is low when working at low power.

Option 4: Large power supply and small power + guide furnace switch dual power supply mode:

Configuration Description: One transformer corresponds to two intermediate frequency power supplies, two intermediate frequency furnace bodies are configured, and two electric furnace changing switches are used for conversion. To achieve a furnace body smelting a furnace body for heat preservation, so alternate work.

Advantages: simple configuration, small investment, high-power configuration smelting, insulation with small power supply. A single transformer reduces transformer air loss.

It can realize the basic functions of one to two devices, one fuse and one guarantee.

The investment cost is low.

Simultaneous casting of the two furnaces can meet the casting of large tonnage castings in the foundry.

Disadvantages: The furnace change switch is a key accessory for the set of equipment, but frequent switching will affect the life of the changeover switch. Pay attention to maintenance.

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