B

#### BobG

- Jan 1, 1970

- 0

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?