How's magnetic sensor works ?

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fosil Member Join Date: May 2007 Posts: 6	How's magnetic sensor works ? 07/21/2007 7:34 PM
	Dear all, Do any of you know how the pedal magnet sensor work in pedicab or electric bike (pedal assist system)? I mean how the sensor read the pedal rpm or torque, I saw there 5 magnets located near the pedal sprocket and the sensor fixed to the pedal's hub. So the sensor in fix and the magnet rotate. before the hub motor work, what happen to the magnet sensor? and when motor is working what is red by the sensor so the controller can connect/disconnect the current from baterry ? Is it magnetic field, magnet induction (i'm sorry if i'm wrong), or what ? And one more thing, The words " pedal assist system ". which one is the main power and which one is the assist power, the hub motor or the pedal power ? Thank's.
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Nigh Guru Join Date: Jul 2005 Location: South east U.K. Posts: 3695 Good Answers: 93	#1 Re: How's magnetic sensor works ? 07/23/2007 9:24 AM
	I would guess that the sensor is counting the magnetic pulses in order to calculate the rotational speed. __________________ I didn't have a really important life, but at least it's been funny (Lemmy Kilminster 1945-2015)
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Faustfix Commentator Join Date: Jun 2007 Location: Germany Posts: 59	#2 Re: How's magnetic sensor works ? 07/23/2007 11:33 AM
	I agree with Nigh. Counting pulses to relate to speed. Plus to register movement. Makes sense cuz otherwise your bike would be going all the time; even without driver (or rider). __________________ If you can't dig it, get a backhoe!
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Yanthram Power-User Join Date: Jun 2006 Posts: 156 Good Answers: 2	#3 Re: How's magnetic sensor works ? 07/24/2007 12:15 AM
	It is easy enough to see how the rotation speed is being measured by the magnets fixed to the driving sprocket and a stationery sensor to count the rotation and time it. However I do not see how the torque is sensed from your description of the system. For a motor pedal assist system the torque exerted would be more important than the speed.
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athmio Commentator Join Date: Jan 2007 Location: greece Posts: 55	#4 Re: How's magnetic sensor works ? 07/24/2007 4:25 AM
	A sensor by that use the HALL effect (if you need to understand how does a magnet sensor works)see google to learn more. __________________ athmio
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athmio (1); Faustfix (1); Nigh (1); Yanthram (1)

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