What is a hall sensor and why do electric bike motors need them?
Posted by Tom Lee on
Hall sensors are in most eBike motors, but not all. Ever heard of them and wondered what they are? They are magnetic sensors which help the controller to know what the position the motor is in as it turns, so that it can keep it turning. Read further for some more detailed info and photos.
A Hall effect sensor is a general purpose sensor and can be used in multiple applications in mechanical/electrical products. They come in many shapes and sizes etc. Incase of ebike the motor can have one to help the electrical controller module know the position of the motor or even calculate revs etc for performance. A simple example is we most all have see similar sensors from bike shops for $15 speedometers for bicycles, one piece is attached via wire to computer the other is attached to spoke (magnet) this magnetic field is sensed from the magnet by the other piece (sensor) to calculate rpm etc
The sensor your talking about goes on the pedals and operates the pedal assist system.
Hall sensors are internal to the hub motor and can’t be accessed with disassembling the motor.
A Hall effect sensor (I think that’s what it is) came with my Chinese electric wheel. It’s in the form of a plastic ring of magnets about 50mm in diameter and a separate metal ring with a connection to the control box. There are no instructions with it, which is annoying…
Reading your explanation above, I assume the ring of magnets must must be fitted concentrically with the wheel, and very close to the pickup ring… I will try to do this, but the plastic ring of magnets on my sensor is just pushed on to the axle stub, which meant that I had to cut it (to get the main cable through) and also enlarge the hole in the plastic to fit the stub axle. The sensor itself is a thin metal ring about 4.5mm diameter with a rectangular plastic object attached (presumably the sensor itself) and a wire going back to the controller. A ring of that diameter doesn’t have any obvious way of being attached in the right place… It’s trapped inside the fork and rattling about because of its very large diameter. Stick it on centrally with some tape wrapped round the fork ends, maybe? That’s about all I can think of, but it’s very rough and ready.
I will try this and see how I get on. If anyone has any further information, I would welcome it (martin.corrick@protonmail.com)
A Hall effect sensor (I think that’s what it is) came with my Chinese electric wheel. It’s in the form of a ring of magnets about 50mm in daimeter and a metal ring with a connection to the control box. There are no instructions with it, which is annoying…
Reading your explanation above, I assume the ring of magnets must must be fitted concentrically with the wheel, and very close to the pickup ring… I will try to do this, but it is not obvious how the parts are attached. It seems that the ring of magnets are just stuck on the wheel with their own magnetic attraction. Is that right?
I will try this and see how I get on. If anyone has any further information, I would welcome (martin.corrick@protonmail.com)