Integrated soft starter for electric motor

A solid state motor starter (10), commonly referred to as a soft starter, is constructed in a manner to be easily manufacturable while at the same time combining all the required components in a relatively small package. A solid state power switch (46, 48) is clamped between a pair of bus bars (32, 42) in an offset manner to accommodate a discrete switching relay (50) mounted in an inverted manner between the line input (36) and the bus bar in communication with the load outputs (44). When in a motor run mode, current is shunted away from the solid state power switching device (46, 48) and through the switching relay (50), a substantially linear current path is achieved to reduce power loss and heat buildup. The arrangement allows for a heat sink (64) mounted to one of the bus bars (32, 42) with adequate spacing between the heat sink (64) and the discrete relay (50) for insertion of a cooling fan (66). Current sensing is achieved with a Hall effect sensor (130) mounted to the bus bar (32, 42) in a small current sensing region (116) that is created by having a pair of slots (104, 105) in the bus bar (32, 42) to direct current. A pair of magnetic pins (124) extend perpendicular from the bus bar (32, 42) to create the magnetic flux for the Hall effect sensor (130) to sense current flow through the current sensing region (116). The Hall effect sensor circuit board (132) also contains a thermistor (134) which is mounted with adequate insulation (150, 154) yet in thermal communication with the bus bar (32, 42) .