Penn Engineering & Manufacturing Corp.

Frank S Nolt

Howard F Hendricks

A brushless DC motor includes a rotor having an iron core affixed to a motor shaft. Permanent magnets are affixed to the core and separated by aluminum inserts which are keyed to the core. An annular groove in one end of the rotor core is dimensioned so that its outer diameter coincides with the inner tips of the aluminum inserts. The inner diameter of the groove and its depth provide only minimal clearance around commutation transistors which occupy the space within the groove. The commutation transistors are affixed and electrically connected to a circuit board which, in turn, is secured to the motor body by attachment to a removable motor end plate. With this structure, the commutation transistors are surrounded on three sides by the rotor and are triggered by its drive magnets. This structure permits the commutation transistor to be triggered by a strong magnetic flux which is more accurately directed through the transistor at its switch plane.

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Elverson, PA, United States of America

Frank S Nolt