March 8, 2006
Today I spent some time thinking about how to best rectify the power from the Stepper Motor.
Cheech was enthusiastic to begin.
I will experiment first with a full-wave rectifier for one phase of the stepper motor, as shown in this schematic.
Each capacitor is predicted to charge to approximately 2 volts, for a total
available voltage of 4 Volts across C3.
Based on the simple LED
tests previously performed, available current should be in the range of 20 to 30
milliamps.
With this circuit, when Pin 6 of the stepper motor is positive compared to Pin
4, C2 is charged through D2.
When Pin 6 is negative compared to Pin 4, C1
is charged through D1.
C3 is charged to the sum of the voltages on C1 and C2, a "Voltage Doubler" circuit.
March 9, 2006
Today I got started on the rectifier board; I soldered up the following circuit on a piece of perf board:
The board:
C5 is a large electrolytic, and is attached to the board with a pair of clip leads.
When Cheech is running in the wheel, C5 develops up to 5 volts across it, and D3
shines brightly.
Several minutes later the D3 is still lit.
By moving a couple of wires, I can run the output form the
phases in parallel, providing less voltage but more current.
I'll
experiment with that when the monitoring circuit is done.
I tested a 24 Volt Stepper motor. Not as good as I'd
hoped.
The motor doesn't produce much of a load on the wheel and doesn't
produce much electricity either.
The motor is used, and may have seen hard
service.
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