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lincpimp
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Join Date: Aug 2007
Location: Slidell, LA
01.16.2009, 12:35 AM

Quote:
Originally Posted by himalaya View Post
No, FET life has nothing to do with the number of poles.

The FETs keeps switching on/off in a certain frequency(eg. 8kHz or 16kHz) no matter how hard or soft you pull your throttle, no matter how fast the ESC commutates(changing motor current directions ). The only difference is the FET on-state time width---so callled Pulse Width Modulation. There are 3 phase coils, so each FET works(switch on/off) only during 1/3 active time, in the other 2/3 dead time it just keeps shut off, no matter how many poles the rotor has.

And, the FET switching in the ESC is just NOTHING. Your computer's CPU power supply converter is also based on FET components, they keep swithing about 100 times faster than your ESC, year after year.
So, as I understand it the esc has a certain rpm limit on 2 pole, why would it have half that limit on 4poles?

The phases much switch more often on a higher pole motor per rotation than on a lower pole count motor. How else does the esc do it?
   
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