Abstract: The Hall effect current sensor is dipped in a coating of magnetically saturable and electromagnetically saturable material, such as a mixture of powdered nickel in an epoxy binder. The coating has little effect on the sensor's ability to sense the magnetic field attributable to current flow in the welding transformers primary or secondary. The coating shields the Hall effect device from potentially damaging electromagnetic radiation which is produced by the welding apparatus as a by-product of the welding operation.

Abstract: A resistance welding controller for dynamically controlling both weld current and weld time in order to achieve a desired .DELTA.R value. The resistance across the weld electrodes is monitored by the controller during the heat-up phase of the weld and compared to target values for minimum resistance (Rmin) and rate of resistance change (dR/dt). If the observed values for Rmim and dR/dt bear a predetermined relationship to the target values, a dynamic correction is made in the percentage heat control setting. The weld is then continued at the revised weld current level until the desired .DELTA.R value is satisfied. If upon weld termination, the observed weld time is greater than the target weld time, an additional correction in weld current is made in preparation for the next weld. In addition, the controller is also adapted to detect newly dressed weld electrodes and automatically respond by reverting to the original weld schedule.

Abstract: A computerized welding control system which is capable of controlling a large number of welding heads from a single processor, the processor being the timing instrumentality for the various portions of the welding cycle. The system also includes standard welding circuitry to control the percent heat and the control of the first electrical cycle of the welding cycle. The system includes a data entry terminal for a set of welders within the group controlled by a single processor, the terminal being capable of addressing the computer to determine the time stored therein for various functions within the welding cycle for a particular machine within the group controlled by the terminal unit. The terminal unit also includes capability of changing the times associated with each portion of the welding cycle.

Abstract: A computerized welding control system which is capable of controlling a large number of welding heads from a single processor, the processor being the timing instrumentality for the various portions of the welding cycle. The system also includes standard welding circuitry to control the percent heat and the control of the first electrical cycle of the welding cycle. The system includes a data entry terminal for a set of welders within the group controlled by a single processor, the terminal being capable of addressing the computer to determine the time stored therein for various functions within the welding cycle for a particular machine within the group controlled by the terminal unit. The terminal unit also includes capability of changing the times associated with each portion of the welding cycle.