This is a 4 pin replacement connector that is found on the back of typical spindles.
The dimensions of this male 4 pin spindle connector is:
Pin spacing (pitch): 0.2" (5.08mm)Mounting hold spacing is 0.7" (18mm)
This connector is mounted on the back of a typical spindle that has mounting dimensions of 18mm or 0.7 inches. There are four connections, three of which are used for the three coil windings for spindles.
The fourth connector can be used for protective earth ground. If there is no way to connect the fourth pin, we typically use one of the screws of the flange to connect the protective earth. This position has continuity with the complete spindle housing.