| 摘要 |
947,119. Rectifying. WILLEM SOMIT & CO'S TRANSFORMATORENFABRIEK N.V. Oct. 2, 1961 [Oct. 13, 1960; Sept. 7, 1961], No. 35531/61. Heading H2F. The motor driving the cooling fan of a welding rectifier is fed by the A.C. component of the rectifier output. When A.C. equipment is to be converted for D.C. welding the rectifier unit may be connected to the A.C. welding transformer by two lines only, no additional connections being required for the fan motor. As the motor operates with current of twice the supply frequency, It may be of smaller physical size than would be necessary if it operated with current at the supply frequency. Several circuit arrangements are described, the Figure shows the motor connected in series with a capacitor, across the D.C. terminals. The motor may be connected through a capacitor, in parallel with a smoothing inductance, and may be supplied through a transformer. An arrangement of relays is described which connects the motor only when the welding current exceeds a certain value, and limits the motor voltage by inserting a resistance in its circuit, or changing the transformer ratio, if necessary. |
