Sine wave controller for hub motor, but the speed.. ?

[TeraH3rz]

Hi,

I'd like to test my motor with a sine wave controller. In China the selection is huge and price range is attempting, but they all lack of specifications. Mainly I guess they are meant for normal size wheel, say 26" or above, but how about smaller wheel size like 12" wheel?, If there is a limit for sine wave output frequency, then with lower diameter wheels RPM would be very low.

I have no exp how they work in real, is there special controllers for different wheel sizes or are the controllers somehow adjustable for top speed based on the wheel size, so if I full throttle then for small wheel I could raise the output frequency and vice versa for bigger wheels to reach the top speed I'm after? Or is it based only for speed sensor output, so If I hit the limit the output freq cant go higher..? but then again how am I going to tell the controller what is my wheel size...hmm.


Jay

 

[AHicks]

The KT based sine wave controllers (the only ones I have any experience with) are going to ask for your wheel size in setup. They're also going to monitor motor rpm. If the signal is not available internally, they'll want an external signal.

 

[TeraH3rz]

The KT based sine wave controllers (the only ones I have any experience with) are going to ask for your wheel size in setup. They're also going to monitor motor rpm. If the signal is not available internally, they'll want an external signal.

Sounds promising, so it's open source project. How do you connect the controller to PC since I dont see any connectors dedicated to that ? Or do I need an LCD module to do the programming ?

Many Aliexpress sine wave controllers, are they somehow related to KT since KT is open source ?

 

[AHicks]

As far as open source, I don't know a thing about it. Too old I guess. I refuse to hook a laptop, or a fancy phone, up to my controller. I use, and love, the LCD3 display for my purposes. It's as sophisticated as I need (want!!) to get.

As far as controllers, they usually say something to the effect they are the KT type, or something to that effect. You could also look to see if a KT type displays are offered as an option. That would be a pretty solid hint.

 

[TeraH3rz]

Just got the Sine wave controller hooked up to my motor and made my first test runs. It runs but I'm only a bit disappointed to RPM.
Since I run on 12S and motor is aswell 48V version, I guess thats it. What can be done?

I assume the KV number is the key, so raising the sine wave frequency motor just wont spin faster due to the limitations of winding inductance issues. But how I can be sure that the controller and motor combination is at optimum max freq or could the motor run even on higher frequency ? I have no accurate data of the motor specs.

Rewinding the motor to alter the KV number is labor related task but what about adding just more Voltage ?

The optimum would be to alter the sine wave and see where are the effciency boundaries of this motor, however with KT controllers this is not possible.

 

[amberwolf]

Sounds promising, so it's open source project. How do you connect the controller to PC since I dont see any connectors dedicated to that ? Or do I need an LCD module to do the programming ?

Many Aliexpress sine wave controllers, are they somehow related to KT since KT is open source ?

KT is not itself open source. KT is just a brand of controller / display, also known as KunTeng / Kun Teng.

There is an open source firmware project here on ES for some of the KT controllers and displays, I believe the threads were started by Casainho so you can search his posts for the threads for details on the project and how you do whatever you need to do with it.