Isn't the dynamotor a virtual short circuit at startup? Lets say 28 volts with 1 ohm of copper wire resistance or 28 amps initially until the dynamotor starts turning and generates a counter EMF. If a short run of a larger diameter wire is used to connect to the battery, the resistance could easily be much lower.

By the time a mechanical meter movement reacts to this high startup current, the current has already fallen to a much lower value. To know what is actually going on I think you need a high current mercury switch, a current shunt and a wide bandwidth CRO with memory, either digital or analog storage.

Jim

Logic: Method used to arrive at the wrong conclusion, with confidence. Murphy

On Wednesday, August 21, 2024 at 11:16:30 PM CDT, William Blodgett via Milsurplus <[email protected]> wrote:

One way to find out is to connect it to 12V car batteries in series along with an adequately sized ammeter and view the draw. No estimations involved.

73,
Bill
AI5RP / KJ5BNE/AE

> On Aug 21, 2024, at 9:29 PM, Hubert Miller <[email protected]> wrote:
>
> I bought at an estate a 24 DC 3.4 A regulated supply. I bought it because "it was dirt cheap", which actually is not actually a good reason.
> Is this supply enough to power a receiver dynamotor, considering start-up inrush ? I last used an actual dynamotor in the early 1970s,
> but that was with a Fair Radio brute force supply. Not that i really like dynamotors, especially for receiver use.
> -Hue Miller