Thyristor Frequency Converters with Output Frequencies 200Hz - 10 kHz for Induction Heating

Thyristor Frequency Converters with Output Frequencies 200Hz - 10 kHz for Induction Heating

TMK Series frequency converters are designed to supply power to equipment that incorporates technology currently used in induction heating, hardening, smelting and/or other applications where a parallel resonant circuit is required.

Principle

TMK Converters consist of an input power supply switch (QS), a controlled rectifier (1), suppressor (2), current converter (3), starting circuit (4) and over-voltage protection (5,6). Power supply is provided from LV or HV mains (50 Hz) through a matching transformer (sold separately).

All regulating, monitoring and control functions are handled by a PLC-based system.  A filtered closed-loop water cooling system is used to control the temperatures of the various electrical/electronic components of the system.

TMK Design

The frequency converter is built into two connected heavy-duty steel cabinets with an IP-43 protection rating.  The left cabinet contains the rectifier, converter, suppressor, input/output terminal boards, voltage sensors and over-voltage protection components, water temperature/flow sensors and a cool-water distributor with its own pressure and temperature sensors.  The lower-half of the right cabinet contains the pump and a water-to-water heat exchanger.  Control circuits including the controller rack and PLC are mounted in the upper-right half.  Forced air circulation is provided for both partitions.  Air cooling is assisted by a water-to-air heat exchanger located mid-cabinet.

Water cooling is accomplished through a two-circuit system. The closed inner-loop provides cooling for the thyristors, transistors, and the suppressor. The circuit is designed with non-ferrous (non-conductive) materials and is filled with a low-conductive liquid. The power circuits contains disc-shaped thyristors (dual-cooled) and IGBT transistors  (also water-cooled).

System temperatures are constantly monitored and regulated by the central controller. The open (outer-loop) system is fed by the customers external water supply. In addition to its enhanced overall design and construction, the new control circuit system makes the TMK-series frequency converters an outstanding technological achievement in the field of current converters.

Advantages of TMK

  • high efficiency throughout the entire output range, over 90%
  • variable range of the output power adjustment from 10% to 100% of the nominal value
  • variable range of the output frequency (fmin–fmax) 30% - 100% of the nominal value
  • a closed-loop cooling circuit with a low-conductive water system helps reduce the negative electrochemical effects to the cooling components and provides improved insulation for the power circuits
  • start and run reliability within a wide range of load impedance
  • converter design also facilitates installation in a dusty environment
  • perfect galvanic separation of control and power circuits
  • clear and simply-interfaced controls provide quick system fault location in order to decrease down-time
  • high-interference immunity for control circuits

TMK Specifications

Frequency converters for induction heating, hardening and melting furnances requiring a parallel resonant circuit: 

Typ U2
[V]
fmax
[kHz]
fmin - fmax
[kHz] 
P2
[kW]
A
[mm]
TMK - F1 600




650
680
0.6
1.5
3
4
6
8
1.5
0.2 - 0.6
0.5 - 1.5
1 - 3
1.5 - 4
2 - 6
3 - 8
0.5 - 1.5
100
100
100
100
100
200
630

120
120
120
120
120
250

160
160
160
160
160


200
200
200
200



250
250
250
250


315
315





1430
TMK - F2 600




800


0.6
1.5
3
4
6
1
1.5
3
0.2 - 0.6
0.5 - 1.5
1 - 3
1.5 - 4
2 - 6
0.4 - 1
0.5 - 1.5
1 - 3
400
400
315
315
200
800
800
630
500
500
400
400
250
1000


630
630
500

315



       

1430



1830

TMK - G1 400
500
10
10
4 - 10
4 - 10
80
100
100
120
120
160
      1430
TMK - G2 400
500
10
10
4 - 10
4 - 10
160
200
200
250
        1430

Frequency converterss for melting furnances with series-parallel resonant circuit:

Typ U2
[V]
fmax
[kHz]
fmin - fmax
[kHz]
P2
[kW]
A
[mm]
TMK - F1 750 1,5 0,5 - 1,5 do 400 1430 
TMK - F2 750 1,5 0,5 - 1,5 do 630 1430

Dimensional sketch

Type marking

Model Number legend for frequency converters:

The composition and design of our TMK frequency converter allows for the further design of other variations of this technology. Please don't hesitate to contact us with your specific requirements. Our engineering team would welcome the opportunity to discuss any technical implementation scenarios with you.

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