[ARC5] Power Supplies Revisited

[J. Forster]

David Stinson wrote:

> OK, let me get back to this for a minute. I did say I had trouble starting
> DM-33s and DY-8s- the transmitter dynos- not the RX ones.
>
> Has anyone found the start surge current on the transmitter dynos? And
> coulombs being what they are, how come
> I can start a DM-33 with only 200,000 ufd?
> 73 Dave S.

Simply put, during the starting transient, you are transfering the stored energy
from the capacitor plus the energy =  (power) x (time) from the supply into the
kinetic energy = (rotor moment of inertia) x (speed) of the dynamotor.

A bigger dynamotor has a bigger moment of inertia and therefore a bigger
transient. The transfer is NOT lossless. An undersized cap will help some.

I suppose a reasonable way to size the cap is to make it big enough that it
behaves like a good battery.

-John