Thanks for the comments! It seems, in this application, to have magnetics
driving magnetics (transformer driving coil of diaphragm pump vibrator). I
could just rewind the pump coil to do the same as the transformer. This
product does several thousand a month, so costs are critical.

THANKS for the ideas thus far!

Harold

>
> The astronomy guys often use small ac motors to drive telescopes These
> motors require very little current Many do this with very small dc to ac
> converters that they can change the frequency of  the ac by small amounts.
> The simplest circuits use a small 110v to 12v ct transformer running
> "backwards"
> with constant current source to the center tap and switching the legs.
>
> There should be many variations found in a google search. One
> typical circuit is
>
> http://www.wvi.com/~rberry/cookbook/120vinv.gif
>
> w..
>
>
>
> Harold Hallikainen wrote:
>
>> I have an application where I need to drive a diaphragm pump (like those
>> used in aquariums) from low voltage DC (battery). Here in the US, these
>> pumps are mechanically tuned to run directly off the 60 Hz line. A
>> single
>> coil on a core moves an armature that has a couple magnets on it. The
>> armature moves back and forth at 60 Hz, vibrating the diaphragm.
>>
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