1. A loom comprising: a frame; a crankshaft rotatably mounted on said frame; a lay pivotally mounted to said frame and operatively connected to said crankshaft; a flywheel secured on said crankshaft; heddle means for forming a shed of warp threads; heddle driving means for driving said heddly means; needle means for inserting weft thread; means mounting said needle means on said lay for reciprocating movement therewith; a main electrical brake-motor; first transmission means for coupling said main motor to said flywheel; stopping means for stopping said main motor when said crankshaft assumes a predetermined angular position at which the shed of the loom is wide open; a sleeve freely mounted on said crankshaft; normally engaged clutch means operatively disposed between said sleeve and said flywheel; manually operable control means for releasing said clutch means; means for making said manually operable control means operative only when said crankshaft assumes said predetermined angular position; second transmission means permanently linking said sleeve and said heddle driving means; an auxiliary electric motor; third transmission means permanently operatively linking said sleeve with said auxiliary motor, said third transmission means comprising a plurality of components at least one of which is carried by said flywheel; and further manually operable control means for controlling the supply to said auxiliary electric motor, whereby said heddle driving means may be driven either from said crankshaft during normal operation of the loom or from said auxiliary motor when the loom is stopped and the crankshaft is held stationary in said predetermined angular position.