L. Schuler Gmbh

Cefin S.p.a.

Zelimir Belamaric

Franz Schneider

Luigi Pazzaglia

Fred E Schalch

Walter Panknin

A control device having a single static converter incorporating a rectifier and stabilizer block and a transistorized inversion block, the output signal of which is controlled by an amplitude and frequency regulator in response to a feedback signal taken off the primary or the secondary winding of the welding transformer. The device features an additional rectifier block located between the output from the secondary winding and the input to the welding rollers.

Control device for resistance welding power supply

An electrical energy source with a static inverter and a welding transformer (12) for a resistance welding machine comprises a first static frequency converter (10) made up of semiconductor elements, the alternating output voltage of which has a frequency and pulse shape which differ from the frequency and pulse shape of the supply voltage fed to the inverter. In this connection, the pulse shape, the amplitude, and the pulse to space ratio are to be variable within wide limits. This is attained by at least one second frequency converter (11) connected in parallel to the first frequency converter (10), wherein the alternating output voltage of the second frequency converter (11) is adapted to be added in phase synchronism to the alternating output voltage of the first frequency converter (10) in the primary circuit of the welding transformer (12).

Electrical power source for resistance welding apparatus

In conventional methods for welding can bodies along their longitudinal seams, high frequency substantially rectangular a.c. currents are used for the welding current to avoid the problem of arcing found in d.c. welders. However, the high frequency a.c. current causes an undesirable degree of heating which produces eddy currents and necessitates cooling equipment. To overcome this problem, a method of producing can bodies welded along their longitudinal seam is provided in which the length of a half wave of the substantially rectangular welding current is matched in length and concurrent with the amount of time required for a can body to pass between the welding electrodes.

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Pully, Switzerland

Zelimir Belamaric