The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 20, 1978
Filed:
Feb. 07, 1977
Ronald Barry Bailey, Erie, PA (US);
Thomas Detlor Stitt, Erie, PA (US);
Dennis Francis Williamson, Erie, PA (US);
General Electric Company, Erie, PA (US);
Abstract
Apparatus for increasing the available regenerative braking energy and for enabling low current control without frequency variation in a time-ratio controlled main thyristor power circuit for a direct current traction motor. A variable impedance element is serially inserted in a motor armature free-wheeling current path between a free-wheeling diode and the motor armature, the variable impedance element preferably comprising a power resistor and parallel connected thyristor. During electrical regenerative braking the thyristor is used to modulate the power resistor to thereby present a continuously variable impedance in the armature current path. During motoring at very low speeds the thyristor can be operated to modulate the power resistor and thus reduce the minimum controllable level of motor current normally limited to commutation current level without the necessity of reducing the main thyristor operating frequency. The thyristor is gated on by conventional means but is gated off by triggering the commutation circuit of the main thyristor, thus eliminating the need for a separate commutating circuit for the thyristor.