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. 31, 1988
Filed:
Jun. 17, 1986
Eiki Watanabe, Inazawa, JP;
Abstract
A control apparatus for an escalator wherein a low speed operation is performed in the absence of passengers at the escalator, and a high speed operation is performed in the presence of passengers at the escalator the alternating current of a three-phase A-C power source is converted by frequency conversion means into a three-phase alternating current of low frequency, with which an induction motor is energized to perform the low speed operation, so that the induction motor is rotated near a synchronous speed corresponding to the low frequency, to realize the low speed operation of high efficiency. Moreover, when passengers have been detected, the frequency of the alternating current from the conversion means is gradually raised, and the conversion means is thereafter switched to the three-phase A-C power source upon detecting the synchronism of this alternating current with the alternating current of the three-phase A-C power source, so that smooth switching free from shocks becomes possible.