KT controller, 9 fet , not an even number ?

[marka-ee]

I'm in the middle of seeing if I can repair a 9 fet KT controller that got an over voltage event and something occurred to me : Isn't 9 an odd number for fets in a 3 phase controller ? Seems like per phase it has 3 , meaning 2 high and one low. Lopsided.
I had a DCDC boost converter go haywire and overvolted it. Blew 6 fets. Anyone know what is doing the 5 volt regulation in there ? It now seems to be making 6 volts and 'm not even sure the cpu survived. A circuit diagram would be so nice.

 

[DogDipstick]

Show us a pic of the board. That might tell us what does what.

 

[marka-ee]

I repaired the 9 fet controller. Now it's a 6 fet controller, got rid of the weaker fets so they are all the same and now it's not lop-sided .

 

[sdobbie]

I have been wondering the same, how can a 9 fet take more current than a 6 fet if there isn't an even number of fets on the upper and lower side of the bridge?

 

[marka-ee]

Exactly, 9 fet must be for marketing reasons ( 9 must be better than 6 , right ? ). Mine had some lower spec. fets paired up there. Honestly, I only felt the controller get mildly warm after climbing a big hill at 600 watts, so I don't know what all the fuss is about . For me staying under 1KW is just fine as I want to go farther more than fast, but fast enough to not be too boring either.
Side Q: so does the open source firmware get you any measurable performance increases? Gas mileage ?

 

[sdobbie]

I have my doubts about the open source software. It is supposedly sinewave but my motor just sounds like it is being driven by a cheap trapezoidal drive. The motor is actually louder on the open source software.