Controls & Transformers

Questions and Answers

This question gets into the design of machine components. Design is beyond the scope of this blog. An article has been written in this blog which describes the components of an MFDC system:



                   Inverter Control Transformer Schematic

Schematic Power Conversion In Control and Transformer of Mid Frequency Inverter

Reference: RWMA Resistance Welding Manual 4th Edition

The model number identifies this as a 120v/60Hz transformer. Contact a local distributor or manufacturer.  They will be able to help identify your transformer.

Design and building of specific equipment is beyond the scope of this blog.

A transformer for a machine/press welder is shown below.

Machine Type Transformer



Reference: RWMA Resistance Welding Manual 4th Edition

This answer to this question is in another article published in this blog copied in full below:


The direct hot-pressing technique of powder materials is referred to as field assisted sintering. In this case resistance heating through the green pressed graphite part would generate the heat. The combination of heat and pressure would generate the desired final properties in the finished graphite product.
The heat is generated per Joules Law:

 Joules Law

Yes, MFDC can be used to generate the heat for hot pressing.

Controls in the marketplace control percent heat. Others control current. Many offer the option of controlling heat or current. Constant current is a common option on many current based controls. The question posed is should we base a weld schedule and ongoing process control on percent heat or current. The answer is simple. Joules Law shows us that current is the most important factor.

 Joules Law

In the formula (I)current is squared. It has the most affect upon the heat.
Therefor we should monitor and control this factor CURRENT throughout the process.

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