I asked this in basics, but didnt get any opinions. Trying it over here if you dont mind.
Anyone know of a site that describes DC motor tradeoffs? I know torque is proportional to current and turns, and there are practical problems with wire size and resistance that limit number of turns, etc. Lets say
I have a 3 pole armature and a 7 pole armature wound with the same number of turns and wire size. Will they have the same torque? Which one will have greater rpm? I know the inductance goes up with turns. Seems like there should be a rule about L/R time constant and RPM somewhere in the rule of thumb list. Some big hefty motors cant be PWMd
faster than a kilohertz or so... is this because of large L? I have am 8.5W motor that reads 12 ohms and 7 mH. Guess thats 1 amp stall torque at 12 volts... but that exceeds the continous power. If its rated at 8000 rpm thats milliseconds per rev. Kind of clobbers my R/L time constant idea huh?