HIMMERWERK SINUS High Frequency Induction Heating Selection

HIMMERWERK SINUS Series High Frequency Induction Heating Generator: Selection, Application, and Engineering Practice

In the field of industrial heating, induction heating technology is widely used in processes such as brazing, quenching, annealing, melting, forging, etc. due to its advantages of high efficiency, precision, and repeatability. The SINUS series high-frequency induction heating generator launched by German company HIMMELWERK covers a power range of 5kW to 25kW and a frequency range of 50kHz to 2000kHz, providing a flexible and reliable solution for small and medium power induction heating applications. This article is based on the technical data of SINUS series products, providing engineers with a comprehensive technical guide from the aspects of model parameters, working principles, selection points, cooling system design, typical applications, and engineering maintenance.

Overview of SINUS Series Products

The SINUS series is a transistor based high-frequency generator designed by HIMMERWERK specifically for industrial induction heating. It adopts IGBT/MOSFET technology and features high efficiency, high reliability, and 100% duty cycle. This series covers 10 models, which can be divided into the following categories based on output power and frequency range:

Power level, model, output power, frequency range, typical applications

5kW SINUS 51 5 kW 500-1000 kHz small parts brazing, fine quenching

5kW SINUS 52 5 kW 1000-2000 kHz surface heating for small parts

5kW SINUS 55 5 kW 200-500 kHz medium depth heating

6kW SINUS 62 6kW 50-200 kHz deep penetration heating

10kW SINUS 101 10 kW 500-1000 kHz universal brazing and quenching

10kW SINUS 102 10 kW 1000-2000 kHz high-frequency surface heating

10kW SINUS 105 10 kW 200-500 kHz intermediate frequency universal

12kW SINUS 122 12 kW 50-200 kHz Thermal and Annealing

25kW SINUS 251 25 kW 500-1000 kHz high-power brazing and hardening

25 kW SINUS 252 25 kW 1000-2000 kHz high-speed surface heating

Core advantages:

High efficiency (>90%), reducing operating costs

100% duty cycle, capable of continuous operation

All parameters are programmable to ensure process repeatability

No need for deionized cooling water, reducing maintenance requirements

Ready to use, no preheating waiting

Compact external heating head that can be connected via flexible cables

Optional Profibus and Profinet interfaces for easy integration

Detailed explanation of technical parameters

2.1 Electrical Parameters

All SINUS series generators are powered by three-phase 400V ± 10% (other voltages can be customized), with a power factor of 0.95.

Model Input Capacity Input Current Recommended Fuse

SINUS 51/52/55 5.5 kVA 9 A 16 A

SINUS 62 6.5 kVA 10 A 16 A

SINUS 101/102/105 11 kVA 16 A 25 A

SINUS 122 13 kVA 19 A 32 A

SINUS 251/252 28 kVA 41 A 63 A

Engineering Tip: In actual power distribution, it is necessary to consider the voltage drop and simultaneous coefficient of the circuit. It is recommended to select fuses one level higher than the rated current (such as 16A corresponding to the actual load of 9A, leaving sufficient margin). The input terminal needs to be equipped with a fast fuse or circuit breaker and comply with local electrical regulations.

2.2 Cooling water requirements

During the induction heating process, power devices (IGBT, MOSFET) and heating coils (inductor) generate a large amount of heat, and water cooling must be used. The requirements for cooling water in the SINUS series are as follows:

Model Water Flow Input Pressure Differential Water Temperature

5-6kW level 4-5 L/min<6 bar>3.5 bar 18-25 ℃

10-12kW grade 6-9 L/min<6 bar>3.5 bar 18-25 ℃

25kW level 10-12 L/min<6 bar>3.5 bar 18-25 ℃

Key points:

No need for deionized water: ordinary industrial softened water is sufficient, greatly reducing operating costs.

Pressure difference requirement: The inlet and outlet pressure difference should be greater than 3.5 bar to ensure sufficient flow rate to remove heat.

Water temperature control: 18-25 ℃ is optimal. Excessive temperature may cause overheating and derating of power devices, while insufficient temperature may cause condensation.

Water quality suggestion: conductivity<500 μ S/cm, pH value 6.5-8.0, no suspended particles.

Cooling system configuration suggestion:

Use a closed-loop cooling system (such as a water chiller) to save water and ensure water quality.

Install flow switches and temperature sensors in the waterway, interlock with the generator, and automatically shut down when the flow is insufficient or the water temperature is too high.

Regularly clean the waterway filter (recommended to check weekly).

2.3 Mechanical dimensions and weight

The SINUS series adopts a split design: the power unit (main cabinet) and the external circuit unit (heating head).

Power level, power unit size (W × H × D), power weight, external circuit size, external circuit weight

5-12kW 380-400×280×320-420 mm 28-33 kg 120×140×240 mm 7 kg

25kW 600×1100×600 mm 110 kg 250×300×170 mm 28 kg

Engineering Tip: The 25kW model has a large size and requires sufficient installation and maintenance space to be reserved (front and rear door opening distance ≥ 800mm). The external heating head can be installed on a robotic arm or fixture and connected to a power cabinet through flexible cables, with a maximum distance of 10-15 meters (considering the influence of cable inductance).

Frequency selection and heating depth

The penetration depth (skin depth) of induction heating is inversely proportional to the square root of frequency: the higher the frequency, the shallower the heating layer; The lower the frequency, the deeper the penetration. The SINUS series covers a wide frequency range of 50kHz to 2000kHz, which can meet different process requirements.

3.1 Frequency and Typical Applications

Frequency Range Penetration Depth (Steel, 800 ℃) Typical Applications

50-200 kHz 1.5-3.0 mm through heat forging, large diameter bar heating, pipe annealing

200-500 kHz 0.7-1.5 mm gear quenching, shaft hardening, brazing

500-1000 kHz 0.3-0.7 mm small parts quenching, fine brazing, wire heating

1000-2000 kHz 0.15-0.3 mm micro parts surface hardening, film heating, sealing

3.2 Selection Guide

Select the scenario of SINUS 62/122 (50-200 kHz):

If the diameter of the workpiece is greater than 30mm, it needs to be heated through heat transfer

Preheating of forging blanks requires a small temperature difference between the core and surface

Annealing and normalizing of thick walled pipes or bars

Select the scenario of SINUS 55/105 (200-500 kHz):

Tooth surface quenching of medium modulus gears (modulus 2-6)

Surface hardening of shaft components, with a hardening layer depth of 0.8-1.5mm

Copper aluminum brazing requires controllable heating area

Select scenarios for SINUS 51/101/251 (500-1000 kHz):

Tooth surface quenching of small modulus gears (modulus<2)

Local hardening of precision parts with small heat affected zone

Hard alloy tool brazing

Select the scenario of SINUS 52/102/252 (1000-2000 kHz):

Surface hardening of small components such as screws and pins

Heating of thin sheet materials (thickness<0.5mm)

High frequency sealing and sealing

Key points of engineering installation and commissioning

4.1 Electrical Installation

Main power supply wiring:

Use 4-core cables (L1, L2, L3, PE), some models require neutral wire N (3 × 400V/N/PE).

Cable cross-sectional area: 5-12kW, recommended to be ≥ 4mm ²; 25kW is recommended to be ≥ 10mm ².

Install easy to operate isolation switches or circuit breakers near the generator.

Grounding:

It must be reliably grounded with a grounding resistance of less than 4 Ω.

Avoid sharing grounding electrodes with high-power equipment such as welding machines and frequency converters.

Electromagnetic compatibility (EMC):

Induction heating generator is a strong electromagnetic interference source, and the power cord should use shielded cables or pass through metal tubes.

The control signal lines (such as Profibus, Profinet, temperature feedback) should be wired separately from the power lines, with a spacing of ≥ 300mm.

Install an EMC filter (optional) at the power input end.

4.2 Cooling System Installation

Use hoses to connect the inlet and outlet of cooling water, with a recommended diameter of ≥ 12mm (inner diameter).

Install manual ball valves and pressure gauges in waterways to facilitate flow regulation.

When the water is first supplied, the air in the pipeline should be drained to prevent local overheating caused by air blockage.

It is recommended to install a conductivity meter in the water tank and regularly monitor the water quality.

4.3 Connection between heating head and coil

Connect the power cabinet and external heating head using the flexible coaxial cable provided with the device.

The coil (inductor) is customized according to the shape of the workpiece, usually wound with rectangular copper tube and cooled by water inside.

Gap between coil and workpiece: generally 2-5mm, the smaller the gap, the higher the efficiency, but it is necessary to prevent short circuits.

Before the first heating, the resonant frequency should be monitored using an oscilloscope or power meter to ensure that the generator is operating within the set frequency range.

4.4 Debugging steps

No load test: Without connecting the coil, check if the generator reports an error (usually no no-load operation is allowed, false load is required).

Water cooling system test: Check for leaks and confirm that the flow switch is functioning properly.

Low power trial heating: Set 10-20% power, observe the heating condition of the workpiece, and adjust the coil matching.

Parameter programming: Set parameters such as power, time, frequency (if adjustable) according to process requirements.

Repeatability verification: Heat multiple workpieces continuously and check temperature consistency.

Typical Application Explanation

5.1 Brazing and Welding

Induction brazing is one of the most common applications of the SINUS series, suitable for copper pipes, stainless steel pipes, hard alloy cutting tools, etc. Advantage:

Localized heating, without deformation of the base material

Controllable flow of solder and beautiful weld seam

Integrated automated production line, fast pace

Parameter example (copper brass joint, diameter 10mm):

Frequency: 300-500 kHz (SINUS 55 or 105)

Power: 5-8 kW

Heating time: 3-5 seconds

Coil: 2-3 turns, with an inner diameter slightly larger than the workpiece

5.2 Surface Quenching

Surface hardening of mechanical parts such as gears, shafts, and guide rails to improve wear resistance. Induction hardening can achieve extremely fast heating rates (tens to hundreds of degrees Celsius per second), followed by water spraying or immersion cooling.

Parameter example (45 steel shaft, diameter 25mm, quenched layer 1.2mm):

Frequency: 200-300 kHz

Power: 10-15 kW

Heating time: 2-3 seconds

Cooling: polymer quenching solution spray

5.3 Annealing and Stress Relief

Internal stress elimination or softening treatment after metal processing, such as cold heading screws and stretched wire. Use lower frequencies (50-200 kHz) to achieve heat transfer.

Parameter example (stainless steel wire, diameter 4mm, annealed):

Frequency: 100 kHz

Power: 6 kW

Heating speed: continuous wire feeding, temperature 900-1000 ℃

5.4 Hot assembly (shrink fit)

Bearings, gears, sleeves and other parts are heated and expanded before being assembled onto the shaft, and after cooling, they form an interference fit. Induction heating has a fast speed and only heats the outer ring, without affecting the inner ring or shaft.

Parameter Example (Inner Ring Heating of Bearing, Outer Diameter 80mm):

Frequency: 10-30 kHz (requires the use of a lower frequency generator, SINUS series with a minimum frequency of 50kHz is suitable for larger sizes)

Power: 10 kW

Heating time: 20-40 seconds

Maintenance and troubleshooting

6.1 Daily Inspection

Check project cycle standards

The cooling water flow rate meets the model requirements daily

The water temperature is 18-25 ℃ per day

Is there any leakage in the waterway? No leakage per day

The power cabinet fan runs normally every week without any noise

Coil insulation has a weekly ground resistance greater than 1M Ω

Clean the water filter monthly without any blockage

The terminals are tightened quarterly without any looseness

6.2 Common faults and countermeasures

Troubleshooting steps for possible causes of fault phenomena

There is no response when starting up, and the main power supply is out of phase; Fuse blown, check input voltage; Replace the fuse

Trip overcurrent during operation; Check whether the coil touches the workpiece during coil short circuit inspection; Reduce power for trial operation

Insufficient heating power, frequency deviation from resonance point; Adjustment of coil turns or parallel capacitance due to poor matching of coils; Consult the manufacturer

Alarm for high water temperature and insufficient cooling water flow; High temperature washing filter; Increase the capacity of the water chiller

Power fluctuation and voltage fluctuation in the power grid; Install a voltage regulator for changes in workpiece clearance; Fixed workpiece position

Profibus communication fault cable breakage; Station address conflict check bus terminal resistance; reconfigure

6.3 Coil maintenance

The coil is a vulnerable component, and after long-term use, its efficiency may decrease due to overheating deformation, oxidation, or scaling inside the copper tube. Suggestion:

Check the appearance of the coil every 500 hours, and replace it promptly if there is any deformation.

Internal water flushing and descaling of the coil: weakly acidic cleaning agents can be used for cyclic flushing (pay attention to discharge after neutralization).

The insulation between the coil and the workpiece (such as wrapping glass ribbon) should be intact to prevent ignition.

Integration and Automation

The SINUS series supports multiple fieldbus interfaces, making it easy to integrate into automated production lines

Profibus DP: Standard optional, can remotely set power, time, read status and alarm.

Profinet: Suitable for industrial Ethernet environments such as Siemens.

Other interfaces: EtherNet/IP, Modbus TCP, etc. can be customized.

Analog interface: 0-10V or 4-20mA control power, combined with infrared thermometer to achieve closed-loop temperature control.

Typical integration solution:

PLC sends commands such as "start heating" and "power setting value" through Profibus.

The generator outputs to the coil and simultaneously collects signals from the infrared thermometer.

After reaching the set temperature, the PLC controls the workpiece to move or spray for cooling.

The heating process data can be uploaded to the MES system for traceability.

Safety precautions

Electric shock hazard: There is high voltage (hundreds to thousands of volts) inside the generator, and non professionals are strictly prohibited from opening the cabinet door. After the power is cut off, wait for at least 5 minutes until the filter capacitor discharges completely before repairing.

Burn hazard: The temperature of the workpiece and coil is extremely high after heating, and insulated gloves or robotic arms should be used during operation.

Electromagnetic field: High frequency and strong magnetic fields pose a fatal danger to users of pacemakers, and warning signs should be set up in the work area. The operator should maintain a distance of at least 500mm from the coil.

Cooling water leakage: If the water cooling system leaks, it may cause an electrical short circuit. Circuit breakers with leakage protection function should be used, and leakage detection sensors should be installed.

Fire prevention: The heating area should be kept away from flammable materials and equipped with fire extinguishing equipment.