Transformers for resistance welding

We offer solutions for all resistance welding processes:

• Spot welding (manual and robot guns)

• Fine spot welding

• Projection welding

• Seam welding

• Flash welding

• Wire mesh welding

• Capacitor discharge welding

The transformers are used in both stationary and flexible robot welding systems, are available in a broad output range and can be adapted to all mains voltages and frequencies on the primary side.

It can be decided whether the welding system is to be operated directly at the power supply (50/60 Hz) or whether an inverter is to be used between the welding transformer and the power supply.

A power supply via an inverter offers the following advantages:

• Connection to a 3-phase network with symmetrical phase loading and insignificant idle power consumption.

• The transformers can be operated with other frequencies (e.g. medium frequency at 1000 Hz)

As a rule, medium-frequency welding systems generate direct currents. This prevents huge inductive losses in the welding circuits.
Mains frequency transformers ( 50 / 60 Hz ) can be alternatively complemented with rectifiers and then also operated as transformer rectifier units (single- or three-phase).

EXPERT boasts a comprehensive product range. Configurations to comply with all major standards are available.

We would be pleased to advise you when selecting suitable welding controls.

Product areas
EXPERT Transformatorenbau Transformers for robot and hand guns

Transformers for robot and manual welding guns

In addition to transformers for medium-frequency welding systems, EXPERT also offers a wide range of mains frequency transformers.

Standard series, special solutions and adaptions are all possible.

Moreover, we also stock a large selection of transformer spare parts, including for transformers compliant with older regulations and standards.

EXPERT Transformatorenbau​ Medium and high frequency transformers

EXPERT Transformatorenbau​ Medium-frequency transformer rectifier units (MF DC Units) and High-frequency rectifier units (HF DC Units)

MF DC Rectifier Units │Series MF2​

EXPERT Transformatorenbau MF2-6,4-5,0-TM-M6-1B

EXPERT Transformatorenbau MF2-8,4-5,0-TM-M6-1B

EXPERT Transformatorenbau MF2-8,4-5,0-TM-M8-1B

EXPERT Transformatorenbau MF2-8,4-5,0-TMUR-M6P-1B

EXPERT Transformatorenbau MF2-8,4-5,0-TMUeR-M8Pr-1B

EXPERT Transformatorenbau MF2-8,4-5,0-TMUeR-M8P-1B

EXPERT Transformatorenbau MF2-8,4-5,0-TM-M6-600V-1B

EXPERT Transformatorenbau​ MF DC Rectifier Units │Series MF3​

EXPERT MF3-9,3-6,5-TM-M8-2B

EXPERT MF3-12,5-6,5-TM-M8-2B

EXPERT MF3-9,3-6,5-TM-M8-2B-635V

EXPERT MF3-9,3-6,5-TM-M8P-2B

EXPERT MF3-12,5-6,5-TM-M8P-2B

EXPERT MF3-9,3-6,5-TM-M8Pr-2B

EXPERT MF3-9,3-6,5-TMUS-M8-2B

EXPERT MF3-9,3-6,5-TMUeR-M8P-2B

EXPERT vMF3-12,5-6,5-TMUeR-M8P-2B

EXPERT MF3-9,3-6,5-TMUeR-M8Pr-2B

EXPERT Transformatorenbau​ MF DC Rectifier Units │Series MF4​

MF4–6,4–7,2-TM–M8–1C

MF4–9,3–7,2-TM–M8–1C

MF4–9,3–7,2-TM–M8–1C

MF4–12,5–7,2-TM–M8–1C

MF4–16,0–7,2-TM–M8–1C

MF4–6,4–7,2-TM–M8P–1C

MF4–9,3–7,2-TM–M8P–1C

MF4–12,5–7,2-TM–M8P–1C

MF4–16,0–7,2-TM–M8P–1C

MF4–6,5–7,2-MUR–M8P–1C

MF4–9,3–7,2-MUR–M8P–1C

MF4–12,5–7,2-MUR–M8P–1C

MF4–16,0–7,2-MUR–M8P–1C

MF4–6,5–7,2-MUeR–M8P–1C

MF4–9,3–7,2-MUeR–M8P–1C

MF4–12,5–7,2-MUeR–M8P–1C

MF4–16,0–7,2-MUeR–M8P–1C

EXPERT Transformatorenbau​ MF DC Rectifier Units │Series MF8/MF100​

MF8-8,9-6,5-TMUeRF-M8Pr-1G (MF100)

MF8-8,9-6,5-TMUeRF-M8Pr-635V

EXPERT Transformatorenbau​ MF DC Rectifier Units │Series MF9​

MF9-13,2-10,0-TM-M8Pr-2E

MF9-13,2-10,0-TM-M8Pr-1E

EXPERT Transformatorenbau​ HF DC Rectifier Units │Series MF10 / 10 kHz​

MF10-11,1-6,0-TM-M8

MF10-11,1-6,0-TMUeRF-M8Pr

EXPERT Transformatorenbau​ HF-Transformator-Gleichrichtereinheit | Reihe MF10​

MF10-11,1-6,0-TM-M8

MF10-11,1-6,0-TM-M8Pr

EXPERT Transformatorenbau​ Mains frequency transformers for welding guns

EXPERT Transformatorenbau​ Transformers for stationary resistance welding applications

Typical applications:

• Spot welding

• Projection welding

• Seam welding

• Flash butt welding...

Multiwelding transformer

Applications:

• Spot welding

• Projection welding

• Seam welding

• Flash welding

• Integrated in multi-point and standard machines

Properties:

• Compact, fully cast design

• Secondary connection via standard welding cable (air- or water-cooled)

Output:

• 25 ... 180 kVA (50% duty cycle)

Standards:

• DIN44766

• ISO 5826-7284

• AUDI-VW-39-V-5711

• M.B. 15.19.030

• NFA 82041

• Ford UWT 001

• Volvo VOV 8064.822

• VC9H71002

expert trafo C-18,0-100-400-PG42-TM

expert trafo C-18,5-100-400-PG42-TMS

expert trafo C-17,9-115-400-M-M50

expert trafo C-20,0-125-400-PG42

expert trafo  C-20,0-150-400-PG48-M

expert trafo C-22,8-150-400-PG42-M

expert trafo C-25,0-160-400-M

expert trafo C-22,3-100-400-PG48-TM

Description

Compact fully potted design

• Nominal powers ranging from 100 to 200 kVA (at 50% d.f.)
• Secondary voltages (no load) 12,5V to 25 V AC
• Single- or multitap versions

Options:

• Temperature switch (T)
• Monitoring coil for current regulation (M)
• Secondary circuit control (S)

EXPERT Transformatorenbau​ Suspended transformers - connection arrangement D

expert trafo D-18,0-100-400-M50-M

EXPERT Transformatorenbau​ Machine transformers

EXPERT Transformatorenbau​ Machine transformers - connection arrangement F

expert trafo F2-8,0-125-400-TM

expert trafo F2-10,0-160-400-TM

expert trafo F2-12,5-200-400-TM

expert trafo F2-16,0-250-400-TM

expert trafo F2-20,0-315-400-TM

EXPERT Transformatorenbau​ Machine transformers - connection arrangement G

expert trafo G2-12,5-200-400-TMS

expert trafo G2-16,0-250-400-MS

expert trafo G2-10,0-315-400-T

expert trafo G2-13,4-340-400-TM

expert trafo G2-16,0-500-400-TMS

expert trafo G2-16,6-530-400-TM

EXPERT Transformatorenbau​ Transformer based on customer standards

Volkswagen

MF DC units for stationary applications

For high-performance stationary applications, EXPERT has developed a product series which satisfies the special demands associated with very high welding currents and heating processes.

This is a modular system which can be combined in a wide variety of ways and which is based on completely wired individual transformers with rectifier assemblies.

Both welding tasks and heating processes can be performed with direct current.

Applications

• Upset welding

• Butt welding

• Seam welding

• Mesh welding

• Projection welding

• Conductive heating

The medium-frequency transformer units can also be connected in parallel in order, if necessary, to achieve even greater welding currents.

Since these projects are normally very mechanically and electrically demanding, we ask that you get in touch with us.

The various types are classified by means of an unambiguous product description.

Description

EXPERT Transformatorenbau​ Transformers for DC resistance welding, one-phase

EXPERT also manufactures one-phase rectifier units for operation at mains frequency.

The relevance of these systems, particularly in the high current sector, has decreased in recent years. In the interests of uniform power supply loading, modern medium-frequency systems are becoming increasingly popular for the relevant applications.

If required, we would be happy to offer you solutions based on one-phase power transformers with downstream high-current rectifier

EXPERT Transformatorenbau​ Transformers for DC resistance welding, three-phase

With high welding currents with single-phase welding systems, the power supply is subjected to significant unsymmetrical loads.

In addition to inverter-based welding systems, three-phase transformers with downstream rectification can also be used. The load is then distributed evenly over three phases.

Further advantages of three-phase welding transformers with rectifiers:

• Compensation of inductive secondary circuit losses

• Very high welding currents are possible

• Minimal ripple with 6-pulse rectifier circuit

EXPERT has developed a modular system for the configuration of transformer rectifier units for mains frequencies of 50 to 60 Hz which covers a broad spectrum of possible applications.

Type designation of transformer rectifier units

The transformer rectifier units are assigned an unambiguous designation with respect to both the type series and the individual type.

The series defines:

• Connection configuration of the transformers used

• Continuous / pulsed operation

• Permanent DC current of series

The type designation defines:

• DC voltage

• Power

• Mains voltage

• Monitoring options

EXPERT has been building and developing pulse transformers for capacitor discharge welding applications for many years.

This process is characterised by the very high application of energy into the workpiece in a short period of time (typically 10-60 ms).

The energy for the welding process is stored in capacitor banks.

Through targeted discharging via a matching transformer, a current pulse is generated which welds the components together. The welding process itself involves projection welding in most applications.

In order to save large amounts of energy in the capacitors, relatively high charging voltages are required. Typical charging voltages are 2000 to 3000 V.

Thanks to the application of high levels of energy, this process enables large-sized components and critical material combinations to be welded. For example, it is used to weld gear wheels in the automotive industry.

Optimal energy efficiency is a key characteristic. Only very small heat affected zones are created in the material with welding processes. The energy is used almost exclusively to melt the materials together at the point of connection.

Welding currents of up to 1,000,000 A have been achieved in systems with EXPERT transformers.

Another advantage of capacitor discharge welding is the relatively low loading of the power supply since the capacitors, as energy buffers, are able to be recharged evenly during the breaks between welding.

These systems are used predominately for large-scale production at automated joining stations.

The matching transformer (pulse transformer) not only serves to ensure an optimal energy supply for the joining process but also, with its design and configuration, plays a key role in determining the timing of the welding current (pulse form) and thus also the welding process.

EXPERT boasts many years of experience in the dimensioning of pulse transformers in the high-current sector.
In-house calculation and simulation tools enable transformers to be ideally designed and adapted to meet customers’ requirements.

We would be delighted to use our experience to optimise your welding processes.