Hello guys, I'm new to this website and relatively new to electronic components.
I have this 250w 24v speed controller that got too hot and burned a resistor. After that incident whenever I connect the battery to the speed controller, the motor automatically starts running at full speed. Ive tried removing the throttle cable and what not on my ebike. But to no avail.

Whenever I run the controller one of the 2 mosfets get really hot, just in 1 to 2 seconds. I have tried checking the continuity, and all the pins are continuous. The model is nec k3511, and I can't find a replacement here, is there a substitute for this mosfet?

 

Hello guys, I'm new to this website and relatively new to electronic components.
I have this 250w 24v speed controller that got too hot and burned a resistor. After that incident whenever I connect the battery to the speed controller, the motor automatically starts running at full speed. Ive tried removing the throttle cable and what not on my ebike. But to no avail.

Whenever I run the controller one of the 2 mosfets get really hot, just in 1 to 2 seconds. I have tried checking the continuity, and all the pins are continuous. The model is nec k3511, and I can't find a replacement here, is there a substitute for this mosfet?

Asian semiconductor part numbers leave out the; "2S" prefix - you should be able to find the data sheet if you search on the complete number.

 

Asian semiconductor part numbers leave out the; "2S" prefix - you should be able to find the data sheet if you search on the complete number.

Hey, thanks for the answer, I've searched for it before too, and found the data sheet. But as I previously said I'm relatively new to electronic components, and I don't have much knowledge about it. Could you help me find a replacement? I'd be very grateful. Thank you anyway for the answer.

 

Hey, thanks for the answer, I've searched for it before too, and found the data sheet. But as I previously said I'm relatively new to electronic components, and I don't have much knowledge about it. Could you help me find a replacement? I'd be very grateful. Thank you anyway for the answer.

Voltage and current ratings of the replacement must be equal or greater.

RDSon should be equal or lower.

VGSthr should be close to original value in case its driven by a logic device with limited voltage swing.

If its a PWM controller - there could be a switching speed issue to watch out for.

A straight series pass regulator will dissipate a lot of heat - power rating and case thermal resistance will be important.

 

Voltage and current ratings of the replacement must be equal or greater.

RDSon should be equal or lower.

VGSthr should be close to original value in case its driven by a logic device with limited voltage swing.

If its a PWM controller - there could be a switching speed issue to watch out for.

A straight series pass regulator will dissipate a lot of heat - power rating and case thermal resistance will be important.

Thank you very much sir. That will be very helpful, although it would be great if you could tell me some alternatives for this mosfet, you seem to be an expert in this field, while I'm just a 12th grade student. No problem if you can't do it, thank you anyway.

 

Thank you very much sir. That will be very helpful, although it would be great if you could tell me some alternatives for this mosfet, you seem to be an expert in this field, while I'm just a 12th grade student. No problem if you can't do it, thank you anyway.

I'd have to go through all the possible alternatives, just like you should.

Some manufacturers published parametric comparison tables that narrow down a suitable device.

There are probably online forms that you enter the essential parameters and it presents a list of suggested devices.