Forwarded: Re: Flywheel encoder patterns

[RABBITT_Andrew at mv8.orbeng.com.au]

one of the problems you will run into with a hall-effect sensor is 
the tooth width.  Most sensor will switch low several mm before the 
centre of the sensor and the tooth edge coincide, and switch high 
again several mm afterwards.  This will limit your tooth width and 
hence your resolution for a given diameter.  We find that at about 220 
mm dia (flywheel size), the best H-E sensor we can get will allow us 
60 teeth without resorting to teeth that look like feeler gauges.

Andrew Rabbitt

From: crsm at oroboros.demon.co.uk:smtp
Date: ## 12/08/96 18:03 ##
In message <19961207053527.AAA4538 at LOCALNAME>, Roger Feingold <rfpro at pos
toffice.worldnet.att.net> writes
>Been following your discussions and I was wondering if you have a sensor for
>your application. If you have an engine operating at redline, the crankshaft
>pulse rate might be beyond the response of the sensor, especially if you
>have 180 or 360 pulses per revolution. 
>
If it's a variable reluctance sensor then you might be correct, but I
think you'll find that a Hall effect sensor will have plenty of
bandwidth.

Bye,
-- 
Chris Morriss