Alt-BEAM Archive
Message #01121
To: "'Steven Bolt'" sbolt@xs4all.nl
From: Wilf Rigter Wilf.Rigter@powertech.bc.ca
Date: Mon, 1 Mar 1999 13:28:22 -0800
Subject: [alt-beam] Re: pocket motor-tester / BEAM multi-meter
The stored energy goes up with the square of the voltage ie double the volts
= four times the energy. Now add some variable PWM to "regulate or shape"
the output current and it is possible to optimize the electrical to "useful"
mechanical energy conversion. This could be a small mod to the PWM circuit
in
http://www.xs4all.nl/~sbolt/Images/smdFotovoor_schema.gif
to increase the duty cycle of the oscillator inversely proportional to the
supply voltage. Interesting to see the evolution of the circuit since 1996.
Wilf Rigter mailto:wilf.rigter@powertech.bc.ca
> -----Original Message-----
> From: Steven Bolt [SMTP:sbolt@xs4all.nl]
> Sent: Monday, March 01, 1999 12:20 PM
> To: beam@corp.sgi.com
> Subject: Re: pocket motor-tester / BEAM multi-meter
>
[Wilf Rigter] snipped
> Note that the same amount of energy can be put in small and large
> caps - its the combination of farads and volts that counts. The
> small solar panels limit us to low voltages, but it does make a
> difference whether you charge a cap to 2V or 2.5V. The latter takes
> longer, unless you use a smaller cap.
>
> A higher voltage in a smaller cap tends to be harder to convert
> into acceleration from stop than a lower voltage in a larger cap,
> given the usual motors. But to make a valid comparison, you'd have
> to change both cap and voltage to match the individual motor, while
> keeping the charge time constant. Using a solar cell, you won't be
> entirely honest, because that will give the advantage to the lower
> voltage. You need a current source.
>
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