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. 28, 2002
Filed:
Feb. 14, 2001
Applicant:
Inventors:
Assignee:
Sunonwealth Electric Machine Industry Co., Ltd., Kaohsiung, TW;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G05B 5/00 ;
U.S. Cl.
CPC ...
G05B 5/00 ;
Abstract
A fan motor having a two-step speed control includes a buffer circuit, a control voltage terminal, and a fan. The buffer circuit is mounted between a voltage source and a source terminal of the fan. The buffer circuit includes a resistor and a transistor. The control voltage terminal is connected to a transistor of the buffer circuit to control conduction or non-conduction of the transistor, thereby changing the voltage of the source terminal of the fan. The varying voltage waveforms are smooth linear waveforms such that rotating speed of the fan is increased or decreased gradually during switching between a low-speed operation mode and a high-speed operation speed.