wesnewell wrote:They aren't fake, otherwise they wouldn't work. Check the International Rectifier website and you will find that IR is not part of the part number stamped on parts. Are these made by IR? Don't know. Don't care. Didn't look close enough. Wait, I've got one open.... Why yes they are The IR logo is below the part number. Not that it makes a bit of difference. They could still be fake.
please read the first 2 pages of this thread. there is a statement there are no fb4110 fets produced by IR.
i know this is about 4410 fets, and the other thread is about 4110 fets. but the same story applies for the 4410 fets i think
what the difference is, they probably will not handle the current they are rated for in the specsheet
Black6spdZ wrote:Correct me if my calculations are wrong, but I measured 0.3 ohms between each of my phase windings on my 48v 1000w motor. So if your supply was a consistent 72v / 0.3 ohms the max current between each phase would be 240 amps. If this current was shared between 5 Fets such as this controller each would have to carry 48 amps.. well within a 96A tolerance... and thats if the power was held on 100%.. but it is pulsed and modulated so never would see that amount of current.. besides the controller will power down the motor if it detects its stalled anyway.
the current is shared by 2 fets. (i think on the high side)
the current is shared by 3 fets on the low side (or the other way around)
as an example:
the current goes from the + of the battery to the high side fets(phase A)
the current goes through the motor coils
the current goes from the low side fets (on phase B) to the battery -
this is 1 step from the 6 step commutation in a brushless controller.