So I am tinkering with making a circuit that will allow a motor to generate power to charge a battery. I have this, what I presumed to be an, AC induction motor I salvaged from an old Christmas decoration.
After removing the motor from its casing, I have learned it is a synchronous motor.
This one with the ratings of 120VAC 3.8W 4.2/5 RMP
It can output upwards of 200 Volts AC in short circuit (or DC using a rectifier bridge) at ~ 6.7mA. I could only get the amperage reading from a short circuit through the rectifier. Could be my $7 multimeter not doing well with AC or my ignorance on reading AC amperage.
Strangely enough (at least to me), no matter how I worked it: the amperage would stay at a consistent cap of ~ 6.7mA. In my tinkerings I figured out there is, at least almost, a straight line which shows that the resistance given to the circuit will output a maximum voltage I can get from the motor itself.
The diagram posted is a test circuit to gather data points on this.
I'm wondering if there is anyone with an idea as to what is causing this phenomena?
Here is a chart and graph of the voltages across the entire circuit (from either end of the rectifier bridge), given the different values of R1.
Definitely some good answers. Not sure which is the best answer. I appreciate all of the input, and will select the best answer once I get back from work and have time to do some more testing, and take apart the motor to see what's really going on inside.
To clarify: the end game is to maximize on incoming voltage so I can reduce the voltage later in the circuit and bump up the amperage to charge a battery somewhat efficiently. Also to understand why there seems to be this constant 6.5mA coming from this motor.
I may just go back to my research and choose a best answer for now. If I run into anything interesting down the road, I'll make sure to post again.