Controls & Transformers

Questions and Answers

Due to the high currents that are present in a control cabinet it is necessary to isolate any connections to the cabinet that can create a potential path to ground. Water is one of these. Therefore special attention to the connectors through the cabinet must be made to insure the fittings are electrically isolated.

Bulkhead Water Fittings

These fittings insure that the water system will remain electrically neutral.

Reference: RWMA - Resistance Welding Manual 4th Edition

                   AWS Standard: J1.2 Guide to Installatio and Maintenance of Resistance Welding Machines

Many controls are capable of monitoring and storing the actual weld parameter data generated during a weld. We are talking about the actual weld current, voltage, displacement and any other parameters.  This data is maintained for a finite period of time in the control. At the end of this time it is erased or can be downloaded for storage.

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Weld controls are incorporated into many automated systems. The weld control is required to take signals from and communicate back to the main system in all of them. Communication in the numerical control environment is normal and a given for weld controls. The weld control runs the actual welding operation but the rest of the automated machine operations are controlled by the central machined communications center. This center may also be a storage center for the weld parameters that will be downloaded from the weld control for each weld. The ability to exchange data both directions is limited by imagination only.

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Adaptive controls monitor one or more weld conditions which can be directly traced to nugget quality. These controls monitor feedback within the first milliseconds of the weld initiation. Based on this instantaneous feedback the control makes adjustments to inputs and can change the weld parameters to correct the forming weld nugget. The goal is to produce a quality weld nugget each and every weld. The controls are in the marketplace and are being used.

Reference: RWMA - Resistance Welding Manual 4th Edition

During welding operations some high alloy materials become brittle in the area near the nugget due to the cooling rate. The parts in fact are quenched in this area and are brittle. Tempering will alleviate this quenched condition. This means bring the material back up to a modest tempering temperature and hold briefly and then cool slowly.

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