The 18v drill motor is dc right ;)
I opened up the datasheet on the k2232, and you look fine with using that (max 60v
25amps).
hmm.. dunno.. but there are geniuses around here..
so they will know something
Lee
----- Original Message -----From: Ben MatthewsSent: Friday, February 18, 2005 9:11 PMSubject: [AVR-Chat] Motor Control ProblemsHi,
I am a 15 year old high school student using a tiny 26 on an odyssey
of the mind project (we have a competition next week :) ). we are
building a vehicle based on an 18 volt drill motor. i have built an H
bridge based on the design on page 263 of "The Robot Builder's
Bonanza". I am using BUZ11 n channel mosfets. I am also using a k2232
(also a n channel mosfet) to drive the h bridge between ground and the
rest of the H bridge. i am using diodes from source to drain. I am
using PWM on the avr to control speed at just under 4 kHz and about a
40% duty cycle. everything works well in testing using a 7.2 V nicad
and a small radio shack motor. when i try to connect to the drill
motor and the 18V motor the cmos buffer i am using between the avr and
the h bridge ( 74hc244e i think) smokes and has visible melting after
the circuit works for a couple seconds. The drill motor draws just
under 10 amps under load. i am going to try adding a capacitor
tomorrow to reduce electrical noise but i was wondering if any one
else has any suggestions for me?
Thanks in advance for any suggestions
Ben Matthews
New York, USA