DC brushless motor, magnetic bearing device and turbomolecular pump device
Number of patents in Portfolio can not be more than 2000
United States of America Patent
Stats
-
Feb 6, 2001
Grant Date -
N/A
app pub date -
Apr 26, 1999
filing date -
Apr 28, 1998
priority date (Note) -
In Force
status (Latency Note)
Importance
Abstract
A turbomolecular pump device having a DC brushless motor provided with a simplified rpm detection mechanism is provided. A pickup coil for detecting a magnetic flux produced by a permanent magnet of the DC brushless motor is built in the motor. Namely, a small size, low cost, simple and strong pickup coil is disposed in a space between the permanent magnet (rotor) of the DC brushless motor and the motor drive coil (stator coil). The magnetic flux produced by the permanent magnet in the pickup coil is detected. This is converted into an rpm signal of the DC brushless motor by a sequence controlling circuit. It is supervised whether or not the overspeed is performed. Then, when the overspeed is detected, an interruption command is fed to the power source breaker so that the supply of the power is forcibly interrupted to thereby stop the DC brushless motor.
First Claim
Family
International Classification(s)
Cited Art Landscape
Patent Citation Ranking
Recipient Email Address
Recipient Email Address
Comment
Recipient Email Address
Add to Portfolio(s)
To add this patent to one, or more, of your portfolios, simply click the add button.
This Patent is in these Portfolios:
Add to additional portfolios:
Last Refreshed On:
Changes done successfully