[Milsurplus] Dynamotor power source question

[wf2u at starband.net]

Jim,

Sometimes a 5V power supply is adjustable enough to get the voltage up
close to 6V.
A dynamotor won't be damaged by undervoltage, but for the same wattage out
it'll draw more current with lower input voltage than with the rated
input. In other words, if you need less than the rated output current (and
voltage of course), figure the wattage, and make sure the primary doesn't
exceed the rated input current, otherwise it'll overheat.
The other thing to take into consideration is the starting current of the
dynamotor, which can easily exceed 10 times the rated input current
momentarily, causing the supply to current limit (in those power supplies
which have this protective feature), and never letting the dynamotor
start.
The best way to use a power supply which is rated close to the dynamotor
rating in amps, is to hook up a lead-acid battery in parallel with the
supply, letting it tricke charge (adjust the supply voltage), and the
battery will take care of the current surge at startup.
That's the way I use all my dynamotor powered military radios.

73, Meir WF2U
Landrum, SC

> I have a several 6V and 12V dynos and would like to power them using
> either linear or (quiet) switcher PSUs. Online, I have found many very
> affordable 5V linears w/the amp rating I need but wonder if this will
> run a 6V dyno w/o damaging either unit.
>
> Jim Falls
> KG6FWT
> Eureka, CA
>
>