How do pedelec sensors work? are they basically on/off or do they have some sort of way of measuring pedal speed/effort.
Tech question
- Thread starter wurly
- Start date
Depends on the sensor, my Wisper measures speed and direction using magnets. Others also measure pressure IIRC.
The Kalkhoff electric bikes use Panasonic's torque sensor. Rather than being simply on/off, it does measure the pedalling effort and uses it to manage motor output. It uses a non-contacting magnetic sensor using an amorphous magnetic alloy. There's a small diagram of the component on the page below
Panasonic pedelec system used on Kalkhoff electric bikes
This means it can detect torque without impeding pedalling. Clever really!
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Yes, the Panasonic system is the best of all, extremely sensitive and seamlessly combining torque sensing with rotation sensing.
Other sensor forms can be a ring of small magnets in a disc on the pedal crank, the passing of the magnets read by a Hall sensor, which is a type of transistor that detects magnetic fields.
Another type has an infra red emitter and a photocell opposite it with vanes passing between to give the pulses, and pedelec sensors can also be built into rear hub motors.
These signals can just be read by the controller for occurrence to indicate rotation, or the rate of rotation can be used to set various things like maximum speed permitted, degree of power available at various speeds etc.
These magnet or vane types cannot sense rider effort of course, only that the the pedals are turning, and some form of effort sensing such as a strain gauge is also needed if pedal effort needs to be measured.
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Other sensor forms can be a ring of small magnets in a disc on the pedal crank, the passing of the magnets read by a Hall sensor, which is a type of transistor that detects magnetic fields.
Another type has an infra red emitter and a photocell opposite it with vanes passing between to give the pulses, and pedelec sensors can also be built into rear hub motors.
These signals can just be read by the controller for occurrence to indicate rotation, or the rate of rotation can be used to set various things like maximum speed permitted, degree of power available at various speeds etc.
These magnet or vane types cannot sense rider effort of course, only that the the pedals are turning, and some form of effort sensing such as a strain gauge is also needed if pedal effort needs to be measured.
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Cadence vs Torque
Hi Flecc
Help!
We have a 905 on trial at the moment using the Panasonic system and we really don't get it! It seems so much less efficient than the simple cadence sensor and a hi/lo power switch, when combined with the throttle this allows the rider to choose exactly how much help they require from 40% up to 100%.
It also means putting the power through the crank which we find reduces range by about 15%.
Am I missing something?
All the best David
Hi Flecc
Help!
We have a 905 on trial at the moment using the Panasonic system and we really don't get it! It seems so much less efficient than the simple cadence sensor and a hi/lo power switch, when combined with the throttle this allows the rider to choose exactly how much help they require from 40% up to 100%.
It also means putting the power through the crank which we find reduces range by about 15%.
Am I missing something?
All the best David
Hi David. The unit only supplies maximum power with a pedal cadence up to 40 rpm, corresponding to 9.4 mph in top gear on a bike set up for the legal limit. Thereafter the power slopes off until there's no more left at 15 mph. So it's counter intuitive compared with normal throttle control, and denies the rider the control you mention.
In addition, the power it does give at any level is directly proportional to the rider input, matching it one to one in standard mode, so if the rider is only putting in 150 watts, that's all the motor will give.
All this means there's a best way to ride it, and as I've often remarked, its completely different from a hub gear and throttle system. In essence, a throttle controlled hub motor bike is a low powered motor vehicle, while the Panasionic system is much more like an ordinary bike in many of it's responses.
It's probably best if you read my article on the system in the tech section which gives the full background to the working:
The Panasonic Motor System
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In addition, the power it does give at any level is directly proportional to the rider input, matching it one to one in standard mode, so if the rider is only putting in 150 watts, that's all the motor will give.
All this means there's a best way to ride it, and as I've often remarked, its completely different from a hub gear and throttle system. In essence, a throttle controlled hub motor bike is a low powered motor vehicle, while the Panasionic system is much more like an ordinary bike in many of it's responses.
It's probably best if you read my article on the system in the tech section which gives the full background to the working:
The Panasonic Motor System
.
Thanks Flecc!
Thanks very much, Flecc I have read your Panasonic thread with great interest, it is a shame that Panasonic don't explain their product as well as you certainly do!
I think however we will continue with the hub motor as though not as advanced in an engineering sense, does do the job required very well and gives us a little more range.
Best regards David
Thanks very much, Flecc I have read your Panasonic thread with great interest, it is a shame that Panasonic don't explain their product as well as you certainly do!
I think however we will continue with the hub motor as though not as advanced in an engineering sense, does do the job required very well and gives us a little more range.
Best regards David
Probably best David. The types are two different markets, very much chalk and cheese.
The Panasonic system is superb at coping with steep hills, but at normal running speeds on the flat a hub motor is potentially more efficient, avoiding transmission losses as it does.
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The Panasonic system is superb at coping with steep hills, but at normal running speeds on the flat a hub motor is potentially more efficient, avoiding transmission losses as it does.
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No... just that one.I am sure you would Tim. And all our other developments I have no doubt!
Regards David
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