PAS sensor question

[morphix]

I noticed you can get these with 12 magnets in as opposed to the more common 5 magnet variety... BMS Battery claim the 12 magnets one makes the motor run more smoothly.

I just wondered if anyone has compared or thinks the 12 magnet one is significantly better?

 

[Old_Dave]

5 magnets = 5 pulses per turn of the crank, 12 magnets = 12 pluses per turn of the crank

Thus.. (I recon, if the sensor is the same simple detector) the 12 magnets will trick the controller into giving a higher assistance per turn, which would be more noticeable at lower speed

But the magic words from BMS are

it can make motor run more smoothly .

"it can" means maybe ..lol

 

[morphix]

5 magnets = 5 pulses per turn of the crank, 12 magnets = 12 pluses per turn of the crank

Thus.. (I recon, if the sensor is the same simple detector) the 12 magnets will trick the controller into giving a higher assistance per turn, which would be more noticeable at lower speed

But the magic words from BMS are

"it can" means maybe ..lol

Hehe. Thanks Dave. I think I'll get one just out of curiosity and do a comparison...will post up the results, but it may be quite some time ;-)

 

[Deleted member 4366]

5 magnets = 5 pulses per turn of the crank, 12 magnets = 12 pluses per turn of the crank

Thus.. (I recon, if the sensor is the same simple detector) the 12 magnets will trick the controller into giving a higher assistance per turn, which would be more noticeable at lower speed

But the magic words from BMS are

"it can" means maybe ..lol

Not necessarily, it depends on the orientation of the magnets. Some have the magnet lying NS in the direction of rotation, so that as each magnet passes, the sensor sees a N and S in quick succession. Others have the magnets perpendiculat to the direction of rotation with alternate magnets orientated alternate directions so that the sensor sees a N and S with two magnets having to pass. I guess there's other possibilities too.

The KU series that BMSbattery sell give power according to the speed of crank rotation, so if they get a higher frequency of pulses, they give higher power at lower cadence. Maybe they wanted to lower the cadence for full power because the old algorithm was useless.