## How does a Brushless Motor throttle work?

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### How does a Brushless Motor throttle work?

As I am on my quest to understand how the brushless motor systems work, I see that understanding what the Hall Effect is and how it is applied in controlling and running an electric motor is one of the most important things to know about brushless electric motor bicycles.

I found this video ( http://www.youtube.com/watch?v=9BFdGtvo9JE ) which talks about 3 different types of Hall effect sensors. the "switch"(tuns on when particular magnetic pole is near it and off when the magnetic pole is moved away from sensor), the "latch"(turns on when certain magnetic pole is near it and stays on until the opposite magnetic pole is near it), and the "ratio metric"(varies out put voltage depending on strength of magnetic field near it) Hall Effect sensors. I am thinking that the typical variable twist grip or thumb lever throttles are using a "ratio metric" which causes a variation inf voltage going through the circuit, based on the strength of the magnetic field of a magnet placed insid the throttle, which will vary depending on what position the twist grip or thumb throttle is at. Is this correct??

I also love this tutorial on the 3 different types of hall effect sensors:

I am supposing that the "ratio metric" hall sensor is essentially a variable resister which changes it's resistance depending on the strength of magnetic field near it. And it requires being fed an electric current to operate, which is grounding in the center prong??

I am wondering which type of hall effect sensors are inside the brushless motors? I am suspect that it is the switch type, which indicates either "on" or "off" state. Although, I am wondering if there may be some advantages to using a "ratio metric" hall effect sensors inside the brushless motors.
csm
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### Re: How does a Brushless Motor throttle work?

Looks to me, the electronic idiot abroad, like you need to remove the question mark from the title.

I think you explained how the throttle works pretty good. When testing halls in a motor, they seem to me like they are acting more like a simple on off though. Likely they are different kinds of halls in the motor.
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dogman
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### Re: How does a Brushless Motor throttle work?

the hall sensors inside the motor are there to tell the controller the position of the magnets on the hub so it know when when to turn on the two phase wires that make the magnetic field that interacts with that magnet, actually many magnets, at the same time. so it is either on or off. and the state remains constant until the magnet moves by again and causes it to change state. so it is called a latching hall sensor.

ratiometric is just like you said, a variable voltage output similar to a big resistor, but without the resistive losses.
dnmun
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### Re: How does a Brushless Motor throttle work?

dnmun wrote:so it is either on or off. and the state remains constant until the magnet moves by again and causes it to change state. so it is called a latching hall sensor.

It is my understanding that a latching hall sensor turns on when a when either a positive or negative field is near it, and that to turn it off requires that field to go away and the opposite field to be near it. I am looking for video tutorial on how the hall sensors work on a brushless motor, indicating how, if it is (bipolor??) latch type, they cause the effect to spin the rotor.
csm
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