Richard (Rick) Karlquist wrote:
>
> john@kk9a.com wrote:
>
>> I have all setup properly, according to sixpack manual it´s connected to a
>> reliable 13.8V power supply (same Kenwood PS I used to power the radio) and
>> not to a 12V wall plug supply.
>>
>
> This whole relay coil voltage discussion makes me wonder whether these
> relays are really "12V" relays, and not 24V relays. True 12V relays
> will typically pull in at 6 to 8V (they just take longer) and will
> certainly pull in at 12V every time. OTOH, 24V relays will often
> sort of work from a 12V supply, especially if it is really 13.8V.
> 24V relays are much more common and often available at reduced prices.
> The relays could also be mismarked. I bought dozens of relays marked
> "24V" that turned out to be 6V relays. The seller did not realize
> this and said he got them surplus or on the gray market. The relays
> were worth far more to me as 6V relays than 24V relays, so I was
> happy.
>
> Supposedly these relays are custom made. In that case, it should be
> possible to wind the coil so it works on, say 10V, so that in any
> nominally 12V system, it would always function.
>
If someone has one of these boxes, and is interested in making some
experiments, the questions could be partially answered.
Just putting a variable voltage supply on and measuring pull in and drop
out voltages is a start.
There's also some application dependent aspects.. what happens to coil
resistance with temperature change? Are there any capacitors in the
circuit? A common technique used to minimize heating in the coil with
solenoids in general is to use a half wave or bridge rectifier into a
capacitor with some series resistance in the transformer or diode.. the
cap charges to 1.4Vrms of the transformer, when the switch is closed, a
higher voltage is applied, but then, under load, the voltage is reduced
(since less is required to "hold" than to "pull in") Diodes in the
circuit also have other effects: the Vf drop changes with current.
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