Motor temp meaurement from Hall sensors?

[vfr400]

Lishui controllers have already got thermal cutout.
Same as most batteries.

That's right, but rather than just cut your power, it would be nice to know when it's going to happen.

 

[WheezyRider]

if you want to read the temperature of the motor, there is a standard solution.
In the 9-pin motor plug, you have 3 phase wires, 5 Hall wires (yellow, blue, green, +5C and ground) and a white wire for the speed sensor.

The output of the LM35 is 10mV per degree C.
Your problem would be how to use the temperature signal.
I guess you can connect the output of the LM35 to a LED to see how bright it glows.
You can get an external speed sensor and use the white wire for your temperature probe. Wire an LM35 temperature sensor to +5V and ground, wire the output of the LM35 to the white wire.
Some guy connects it to an Arduino and insert the temperature into the datastream between the controller and the LCD.

That sounds interesting Woosh, so are you saying there is an LM35 already inside the motor connected to the external speed sensor? Have you got any links to this mod?

 

[WheezyRider]

Yes of course you should care about the temperature but it's an affect you are aware of anyway, when you stress your motor it gets warmer. A temperature readout while interesting to observe wouldn't correct that effect, that's down to you. Unless you have some sort of automatic control system that cuts power at a set temp level like my computer that initiates an action when required, I can't really see the point.

A lot of modern cars come without engine temperature gauges. This is fine for the first 5 years or so, but when things start to age, you can be in with a shock if the cooling system begins to fail and you had no advanced warning of the engine temperature gradually increasing. Once it's over heated, the cylinder head is cooked and it's game over.

The more data you have from a system, the more you can learn from it. And if you are experimenting, you want to see if your modification is improving things or making them worse.

 

[Woosh]

That sounds interesting Woosh, so are you saying there is an LM35 already inside the motor connected to the external speed sensor? Have you got any links to this mod?

you can get them on ebay.
https://www.ebay.co.uk/itm/2PCS-LM35DZ-TO-92-Precision-Centigrade-Temperature-Sensor-For-IC-Low-ImpedanceS/362485729924

 

[WheezyRider]

you can get them on ebay.
https://www.ebay.co.uk/itm/2PCS-LM35DZ-TO-92-Precision-Centigrade-Temperature-Sensor-For-IC-Low-ImpedanceS/362485729924

Ah, ok, I see what you mean now, to cut the wire inside the motor going to the speed sensor and wire that up instead to an embedded LM35 you have to put into the motor yourself.

It's one solution, but it leaves you without a speed sensor.

When I get the chance, I'll hook up an ammeter to one of the Hall sensors and see what happens to the reading during a ride.

 

[WheezyRider]

Standard grade neodymium magnets have a maximum operating temperature of 80 degrees Celsius. When heated above this, they will experience irrecoverable losses in performance. High temperature grades of neodymium magnets with higher maximum operating temperatures are available but are they used ? Good luck Wheezy Neodymium magnets will lose a certain amount of performance for every degree rise in temperature even if the temperature is below their maximum operating temperature. In fact, depending on size, shape, grade and how it is used, a neodymium magnet will lose 0.08%-0.12% of its magnetic strength for every degree Celsius rise in temperature.
https://www.amazon.co.uk/Digitemp-Level-Horizontal-Scale-Thermometer/dp/B00SHCK15C/ref=sr_1_95?dchild=1&keywords=stick+on+thermometer+strip&qid=1594469401&sr=8-95
£2:50 Well spent.

With geared hub motors there are two air gaps between the coils generating the heat and the outer shell, so the insides can be far hotter than the shell.

Those LCD thermometers probably wouldn't last long outside as they are UV sensitive and in the sun they would degrade.

 

[RossG]

A lot of modern cars come without engine temperature gauges. This is fine for the first 5 years or so, but when things start to age, you can be in with a shock if the cooling system begins to fail and you had no advanced warning of the engine temperature gradually increasing. Once it's over heated, the cylinder head is cooked and it's game over.

The more data you have from a system, the more you can learn from it. And if you are experimenting, you want to see if your modification is improving things or making them worse.

Happened to me once many years ago, driving an old Rover flying along a major road with smoke everywhere

 

[scott gaza]

Sure just an idea i had to monitor surface temperature of actual hub PS: i live in Scotland so dont have to worry about the sun