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Old 01-22-2015, 12:12 AM   #1
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Default Measuring rotor strength

Hi guys, a while back I read an article about how to measure stator resistance using some relatively inexpensive and simply equipment + math.

I'm wondering if there is a similarly inexpensive way to measure rotor strength without forking $300 for a proper testing system?

Thanks
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Old 01-22-2015, 01:30 AM   #2
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No problem. You do need a lineair HALL sensor.

https://www.youtube.com/watch?x-yt-c...layer_embedded

Datasheet of the one I used:
http://www.sumzi.com/upload/files/20...9170343315.pdf

Diagram:

To get a good range I had to put the sensor on a 5mm distance.

It is just 20 euro of parts including the meter.
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Old 01-24-2015, 12:38 PM   #3
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How it works ?
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Old 01-24-2015, 01:56 PM   #4
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The SS495 is a lineair HALL sensor (magnetic sensor).
At a 5v voltage its zero point has a 2.5v output. Depending the polarity of the magnetic field the voltage will go up or down and how much is regarding the strength of it. The maximum of 640 gauss has a 2v range.

The used meter works at 9 up to 12 volt so a 5v regulator is needed to make it work on a 9v battery. The meter has a 200mV range and with 2 resistors I could use the full scale of the meter.
The potmeter is just a zero adjust before placing a rotor.
(Be aware the used panelmeter must not have a shared ground from supply voltage to input)

I mounted the sensor at about 5mm distance of the rotor so the magnetic field did show half scale.
Any other rotor will show different values so you can dterm the strength of it and select the best one out of a few.

This thing is made to detect illegal rotors with more magnetic field into a 1 brand/model stockmotor. The motors measured were in between a range of 990 up to 1017. The 1017 was from a person with the fastest motor on the track so yes, a small improvement on the magnetic field can give more performance.

So it does not show a strenth on a right scale but it will show differences between rotors.
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Old 01-24-2015, 02:34 PM   #5
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Thanks.
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Old 01-24-2015, 07:13 PM   #6
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Old 01-26-2015, 09:18 PM   #7
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Anyone out there have an iphone?

This may not be perfect but it's cheap (like, um, free) and works well enough for me to be happy with the measurements I get. I also find it very repeatable.

Get this app...

https://itunes.apple.com/us/app/mmf-...544695183?mt=8

Build a jig that holds your phone and the rotor at a set distance from each other. I used a small plastic block, wood will work too, just be sure the rotor is in a fixed groove that it can rotate in and the phone is held in place as well.

Then...measure the rotor + and - by slowly rotating it around while using this app. The app reads to 999 so you need to set the jig up so that you don't go over this point. My first jig read in the 5-600 range for decent rotors and worked fine. You can set the rotor closer to the phone for finer increments.

So far I have $0 invested and I don't feel that I need anything more to test rotors.
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Old 01-26-2015, 09:31 PM   #8
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Cool!But, how does it work with the iPhone, iPad, ect? Sounds silly, but will it not damage the iPhone?
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