Explosion-protected electric motor having a shaft mounted in a housing, which shaft is led through an output-side shaft leadthrough of the housing and the output side leadthrough has between shaft and housing a gap designed in an ignition transmission-resistant manner, wherein the housing is of pot-like form with a bottom and a cover and a connection box attachment for the cable leadthrough of a stator winding is formed on the cover-side end region of the pot-like housing, wherein an output-side bearing is arranged on a housing outer side of the bottom, wherein a movable bearing supports the shaft in the cover designed as an end shield, wherein the bottom of the housing has the output-side shaft leadthrough, wherein a further bearing receptacle for the movable bearing is arranged in the cover, wherein the bottom has a protuberance which is of cylindrical design, in which are formed a bearing receptacle towards the housing outer side and a section projecting into the housing and surrounding the shaft, wherein the section surrounding the shaft forms with the shaft the gap designed in an ignition transmission-resistant manner, wherein a flange is pushed onto the protuberance, which flange is fastened to the housing by means of a screw, wherein the screw is screwed into a blind hole-shaped threaded bore designed in the axial direction in the bottom, wherein the cover has a further shaft leadthrough, wherein a shaft stub projects beyond the cover and an additional ignition transmission-resistant gap is formed between shaft and cover, wherein a fan wheel is arranged in a rotationally fixed manner on the shaft stub, wherein a rotational speed-measuring device is arranged in a rotationally fixed manner on the shaft stub, wherein a housing-forming covering device is mounted on the cover, which device has apertures for sucking in air, wherein the explosion-protected, pressure-resistant housing of the motor has two spatial regions, wherein the two spatial regions each have a gap, designed in an ignition transmission-resistant manner, towards the outside of the housing, wherein a pressure-resistant compression seal is arranged between both spatial regions, wherein preferably electrical lines are led through the compression seal, wherein an ignition transmission-resistant housing gap is formed between the cover and a pot-like rest of the housing, wherein a connection box, preferably a pressure-resistant connection box, is mounted on the connection box attachment, wherein a further ignition transmission-resistant gap are formed between connection box and connection box attachment, wherein the connection box attachment has a cylindrical opening, the axis of which runs approximately perpendicularly to perpendicularly to a shaft axis, a cylindrical elastic base body with through-holes running parallel to a cylinder axis is inserted with an exact fit into the cylindrical opening, the cylindrical elastic base body is delimited at its circular end sides by a motor-side and an opposite plate having holes corresponding to the through-holes, wherein the motor-side plate is supported on a shoulder in the connection box attachment and the opposite plate is pressed onto the cylindrical elastic base body by a ring element with an external thread which engages in an internally threaded portion of the cylindrical opening.