[ARC5] Power Supplies for Your ARC-5

[Buzz]

I use two of the small riding lawn mower batteries available at walmart =
for about $20 ea.
Buzz


On Tue, 15 Jan 2002 11:35:29 -0500, you wrote:
>
>
>David Stinson wrote:
>
>> The current ratings written on the dynamotors are the running =
currents.  The
>> starting surge current will be much higher.  I don't remember off hand=
 what
>> the starting current for a DM-33 or DY-8 is, but I think it's around =
25 amps.
>> Most of these supplies have protection against surges.
>
>> You can overcome this by using some large capacitors in a bank to =
provide the
>> surge current, while the power supply
>> provides the running current.  24 volts in batteries will also work.
>
>It will take a MIGHTY capacitor bank to start a dynamotor. Simply put:
>
>Q (charge) =3D I (current) x T (time)
>
>Q =3D C (capacitance) x V (Voltage)
>
>therefore I*T =3D Q =3D C*V
>
>in this case, the V is the allowable voltage drop during startup. =
Putting in
>reasonable numbers:
>
>I =3D25 amps, T=3D1 sec, V=3D(28-23volts)=3D5
>
>25 * 1 =3D C * 5;  solving C =3D 5.............. FARADS, ie 5,000,000 =
microfarads.
>
>That's a pretty big capacitor.
>
>Think about floating batteres.. That's what I use for my No 19 MK III =
set, and
>it works just fine. Marine batteries in a fiberglass case are ideal.
>
>Good luck,
>-John
>
>
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