Temp sensors should always be part of your system to avoid overheating motors. They will also help with temp compensation, which is also beneficial for regular FOC commutation. Hot motors simply have a different resistance compared to cool motors and the resistance value needs to be quite accurate for FOC commutation. So Temp sensors sort of make sense and if you have them, you can make best use of them.
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for low power commuters with no risk of overheating it would be very usuell to run it completely without sensors.
Low power boards usually have smaller motors and they can overheat just as fast as bigger motors on higher power builds. And heat is not only coming from Amps, it is also coming from eddy currents at high RPMs (core losses). You can overheat pretty much any motor by just spinning it at max RPM, while pushing only 2-3 Amps. Personally I would always use temp sensors to avoid overheating motors, no matter of the system size.
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Many people run without any sensors to keep it simple. If you setup the correct limits it wont overheat.
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Without temp sensors you will have a hart time to say if you have overheating issues or not. You could guess that you don’t have issues.Unless you actually measure the temp at the winding you never know. Most boards here on the forum have quite some output power and they are all prone of heat building up beyond a critical value for the glue of the magnets, winding insulation or loctite used for holding all bolts in position. A motor that can output 2.5KW peak can maybe output 500W constant. Since we all want to use the peak power of the motors for acceleration and going up hills etc, we always risk to push the motors too hard for too long. The temp sensor will tell the ESC and the ESC will then protect the motor and you, since the motor is also our brakes we rely on.
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This is usually caused by poor routing of the sensor wires by the motor manufacturer, such as having the GND and TEMP wires not parallel to each other and instead each going through a individual slot on the stator, this makes a huge induction looks and the motor spinning causes lot of spikes in the temperature reading
When you are near the temperature limits, this makes it jump up and down and get into the hard cutoff limits
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I never understood how manufacturers thought that cables below spinning magnets are a good idea, especially when they use more than one slot for routing.
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Yeah, makes way more sense to be on the front of the motor, but I guess it’s harder to manufacture
A lot of motors don’t use a support bearing and it would be easy to place the PCB in the front. Even on those designs I have seen PCBs in the back with wires in the slots.
With A.S.S. all of this mess can be eliminated.
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If you have to fill in the temperature when doing ass setup to have the controller use it to determine the resistance when starting, cant you leave the temp sensor out, fill in the temperature when setting it up and determine the temperature of the windings through changes in the resistance of the wires?
Genuinly curious btw, not bashing or something like that.
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In theory yes, but it is not so easy to measure the resistance while spinning the motor at the same time.
Benjamin also thought about it. Maybe in future it will be possible. We also need a method that is relable for all sorts of motors. If you have one defined motor, it might be easier…
Temp sensor cables are not a very big deal and you definitely get reliable readings for all sorts of motors.
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A guide as to where to stick the temp sensors would be dope. I’d love to revive old motors with broken sensors to use as my winter motors.
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Just glue it directly to the windings with some epoxi. Ideally in the front of the motor.
The front is where the phase wires come out?
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I think that’s a yes?
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yes
Yes I have tried it out and it wasn’t working great. But I also don’t have hardware with phase filters to compare with. That’s why I was asking for a video showing hardware with phase filters running ASS a lot better.
The Trampa motors are the only ones I have with a temp sensor and they are broken.
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VESC HD 60T with 160KV 6376 motors.
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Thanks for the video. 
Looks like it is working well. I hear some HFI bleeps when you were rolling backwards but the motors were spinning slowly. Is there some range from 0 to X rpm where it is used for tracking, because from what you said I was only expecting it at 0 rpm?
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