Here's a slow pitch for my first homework question. This happened a long time ago I'm just wondering if I'd tried all I could.
Student comes into the lab. Group project was a windmill with a generator on it. Teacher gave him the "generator" (I'm pretty sure it was some motor). Nice windmill, he made, like a squirrel cage fan out of glued up posterboard. So I take him to electronics.
Hook thing up to bench multimeter in DC, spin. Two volts.
Bench multimeter in AC, spin. Like, no volts.
Tried another meter, same thing. Student insists it should make a bunch of volts.
I put some resistor across the "generator" and put an o-scope in series. I just wanted to make sure this thing wasn't putting out AC or something silly. Only amplitude changed by some mVolts, did not look like ac.
I really wanted to see what kind of motor it was but they'd buried it in wood and I couldn't see it. It spun free so it wasn't like a stepper motor, but certainly nothing real high torque.
The windmill was very easy to spin by hand and my thinking is that if it made any power worth making it would have been harder to turn... Probably so hard that their design would need a gale to work.
My question is what would you have tried?
Student comes into the lab. Group project was a windmill with a generator on it. Teacher gave him the "generator" (I'm pretty sure it was some motor). Nice windmill, he made, like a squirrel cage fan out of glued up posterboard. So I take him to electronics.
Hook thing up to bench multimeter in DC, spin. Two volts.
Bench multimeter in AC, spin. Like, no volts.
Tried another meter, same thing. Student insists it should make a bunch of volts.
I put some resistor across the "generator" and put an o-scope in series. I just wanted to make sure this thing wasn't putting out AC or something silly. Only amplitude changed by some mVolts, did not look like ac.
I really wanted to see what kind of motor it was but they'd buried it in wood and I couldn't see it. It spun free so it wasn't like a stepper motor, but certainly nothing real high torque.
The windmill was very easy to spin by hand and my thinking is that if it made any power worth making it would have been harder to turn... Probably so hard that their design would need a gale to work.
My question is what would you have tried?