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:
May. 01, 1990
Filed:
Nov. 29, 1988
Bernard A Raad, Rockford, IL (US);
Tyrone A Johnsen, Rockford, IL (US);
Sundstrand Corporation, Rockford, IL (US);
Abstract
A starting system for an aircraft propulsion engine. An electrical motor (62 or 122) is mounted within a case (14) in which first and second hydraulic units (102, 104) are operated as part of a constant speed drive transmission. The electric motor accelerates a motor-generator set (24) to a velocity near the synchronous speed. The motor-generator set is coupled to the drive shaft (20) by operation of the hydraulic units as a variable torque link. The electric motor functions both as a heat source of hydraulic fluid contained within the hydraulic pump and motor case during extreme low temperature conditions at which point the starting torque of the motor is initially insufficient to cause rotation of the output shaft and to further accelerate the motor-generator set up to a rotational velocity at which the motor-generator set may be operated synchronously at which the motor-generator set is coupled to the drive shaft (120) by operation of the hydraulic units as a variable torque link to rotate the engine. When the temperaature of the hydraulic fluid within the case is below the stall temperature so that the electric motor has insufficient starting torque to initiate rotation, the heat generated by the windings heats the hydraulic oil to lower its viscosity to a point at which rotation may be initiated to permit the motor-generator set to be rapidly accelerated to operate as a synchronous motor during starting.