Abstract: A three phase motor is constructed with each of the three phase windings thereof split in half so that the motor may be selectively connected for energization from either a relatively high or relatively low source. Motor protectors are provided in the form of a three pole automatic resetting overload relay means and two thermostatic switches. The heaters for the individual poles of the overload relay means are connected in series with a half section of the individual phase windings and do not have to be changed when either high or low voltage energization is selected for the motor. The thermostatic switches are embedded in two of the other three winding sections but electrically insulated from the motor winding. The control contact means of the overload relay means and the thermostatic switches are connected in series with the energizing coil of the electromagnet for the contact through which the motor is connected to its energizing source.

Abstract: A multipole unitized motor starter is constructed of a common base having mounted thereon a disconnect switch, an electromagnetic contactor and a fuse unit connected in electrical series between the switch and contactor. The fuse unit is a plug-in device which is readily removable for service access and when operatively mounted is positioned to permit direct viewing of the switch contacts.

Abstract: Contactors and housings therefor wherein the contactor is provided with blow-out coils brought into circuit by the arc; arc extinguishers; and fuses in series with the contacts; a closing and holding magnet for operating the contacts; anti-single-phasing operation to open the contacts in response to overload interruption by a fuse; the housings being of modular arrangement to form a uniform control center and being provided with racking means for inserting and removing the contactors with the door closed; and means for protecting the operator including the closing off of access to at least the line bus when the contactor is racked out and disabling the racking mechanism when the contactor contacts are closed.