The invention relates to a method and generator for generating a time sequence of EDM pulses having a predefined ignition voltage for electrical discharge machining. An AC voltage is generated from a DC voltage, furnished by a bipolar current source (8-17). The AC voltage is applied to an isolating transformer (27) disposed between the bipolar current source (8-17) and the spark gap (EL, WS). A first pulse capacitor (47, 48, 61, 62) is charged by the bipolar current source (8-17) to a voltage corresponding to the ignition voltage. The ignition voltage provided by the isolating transformer (27) is switched with a selected polarity to the spark gap (EL, WS). |