Single-phase motor starters
OwnerOtto J. M. Smithinventor
Life of this patent
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Abstract
For a three-winding motor, a starting capacitor bank provides balanced currents in the windings, a high starting torque, and unity power-factor current in the single-phase supply line. A run-capacitor bank provides full-load balanced currents and a leading power-factor in the single-phase supply line. The method is applicable to a star or wye winding connection, to a delta winding connection, and to a Semihex.TM. winding connection.
Claims50
In an electrical alternating-current motor driven by a single phase power supply and having at least three motor windings of different phases, a multipole starting contactor and a plurality of starting capacitors including switching means operable during the starting sequence where a first starting capacitor is connected in parallel with a first motor winding, and a second starting capacitor is connected in parallel with a second motor winding.
In an a-c electrical motor driven by a grounded center-tap single phase power supply and having at least three motor windings of different phases with four motor terminals, said single-phase supply having three terminals, means to connect a first capacitor between a first motor terminal and a second motor terminal, means to connect a first supply terminal to said first motor terminal, means to connect a second capacitor between said second motor terminal and a third motor terminal, means to connect a third capacitor between said third motor terminal and a second supply terminal which is said center-tap, and means to connect a fourth motor terminal to a third supply terminal.
In an a-c electrical motor driven by a single phase power supply and having at least three motor windings of different phases, said single-phase supply having two terminals, an inductor and a capacitor, a first winding terminal connected to a first supply terminal, a second winding terminal connected to a second supply terminal, the inductor connected between a third winding terminal and said first supply terminal, and the capacitor connected between said second winding terminal and said third winding terminal.
An alternating-current motor having a two-line single-phase power supply, the motor having at least three motor windings of different phases, said motor windings connected in series with four sequential motor terminals 1, 2, 3 and 4, means to connect a first line of said power supply to the first motor terminal 1, means to connect the second line of said power supply to motor terminal 3, means to connect a first capacitor between motor terminal 1 and motor terminal 4, and switchable means to temporarily connect a starting capacitor during starting between motor terminal 3 and motor terminal 4.
An alternating-current motor with three motor windings with different voltage phases, three motor terminals, a three-terminal autotransformer, a single-phase supply with at least two lines, a first line connected to a first motor terminal, a second line connected to a second motor terminal, one terminal of said autotransformer connected to said second motor terminal, a second terminal of said autotransformer connected to a third motor terminal, a motor-run capacitor connected between the third terminal of said autotransformer and the said first motor terminal, and a plurality of switchable temporarily-connected intermittent-duty starting capacitors, one of said starting capacitors connected between said first and said third motor terminals.
Dependencies are inferred from the claim text.