Can anyone identify ...
- Thread starter racereadyfreddy
- Start date
Images appear in Google search for SY72420 some of which mention 250W, all images show 20" wheels, none I found show voltage.
36V is way more common than 24, there is unlikely to be anything inside that will mind, max rpm will be different, about 1.5 times as high if a 24 V and you give it 36V.
Stick it in a bike, get a controller and lcd that like each other and match the motor cable, and see what happens.
The marking 24/20 does suggest it could be a 24v motor for 20" rim build so one may be best selling it as so, running at 36v just means it will run 50% faster and incur more torque with higher current. The motor with more current will likely run hotter esp at slow speeds.
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Voltage has no meaning. It's for reference only, like 250rpm at 36v, 180rpm at 24V, etc. You can run it at whatever voltage you want with no detrimental effect. The voltage affects the speed it rotates. The higher the voltage, the faster it will rotate. You must test it to see how fast it goes at any particular voltage, then you can determine what voltage it needs to run at the desired speed.
The rotation speed needs to be higher for a 20" wheel compared to a 26" one. The same motor would be used for both - running it with 36v in the small wheel and 24v in the big one to get the same bike speed.
There are only two meaningful characteristics of a hub motor - the rated power and the kV (RPM per volt).
I don't know too much about ebike motors, but I know that applying too much voltage to some types of circuit can burn certain components out. I've since watched a tear-down video of another make of hub, and I have to say the wire used for the windings looked massive though.
You'd have to go into the range of many hundreds of volts to burn a motor by voltage. You'd need enough voltage to overcome the wire's insulation, which is about 200v/microM.
It's current that burns a motor (or any wire), not voltage.
The motor has a power rating of 250w. The controller determines the current, so you must choose a controller that provides the right amount of current considering the voltage, since power = current x volts.
the coils inside the motor are connected to the battery via FET electronic switches, the latter are turned on by the controller for a fraction of milliseconds. The controller will turn off the switches if it detects anomalies like motor stalling.
You need to open up the controller to check the voltage ratings of the key components, capacitors and FETs before connecting a higher voltage battery to it. Post pictures if you need help with checking.
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