| 摘要 |
To prevent the voltage fluctuations when more than one resistance welding machine is switched simultaneously on a supply, a contactless interlock ensures that only one machine uses welding current at a time. A three-bit counter with pulses from a 24V 50 Hz supply passes input pulses to AND-circuits allocated to each welding machine. The second input of each AND-circuit comes from a signal confirming the motion of the electrode of this particular machine. In case of coincidence, the AND-circuit actuates through an amplifier the contactor for the current to the welding machine concerned which ten starts to operate. |
