[time-nuts] No more 60Hz, How do I discipline 120VAC 60Hz from a UPS

[Will Matney]

Don,

The easiest way would be to convert the line voltage to make a 12 Vdc
source, then use an inverter that you can add a xtal control to its
oscillator, or even add a GPS disciplined source to drive it. However, that
won't help with power outage, unless you would use a UPS, or maybe a
generator that will kick in when the line voltage starts to drop. The
transformer to use is a simple 24 Vac, center tap secondary, that you then
use as the primary, and drive it with 12 volts on either side with the
oscillator. You feed the center tap with 12 Vdc, and switch the two outer
legs to ground via transistors or FET's. The secondary is what was the 120
Vac primary, and you have to source for the clocks.

I built a 60 Hz inverter a few years back, and it didn't really require
much. I can't recall the chip I used for the oscillator, but it did work,
and it gave me 60 Hz like I wanted. Most cheaper inverters, if I remember,
run at a higher frequency than that, which are now sold on the market. They
do this to get the transformer size down.

While you're at it, you might want to check the motors loaded rpm in those
clocks to see how accurate they are.

Best,

Will

*********** REPLY SEPARATOR  ***********

On 6/25/2011 at 9:50 AM Don Mimlitch wrote:

>I collect clocks an have many clocks with 60Hz Synchronous Motors.
>
>How would I go about Disciplining a 60Hz 120VAC source from an
>Unintteruptable Power Supply (UPS)?
>
>This would solve both my problem with power outages and the new problem
>of possibly undisciplined power from the power companies (Henry Warren
>must be rolling over in his grave!)
>
>I have no Idea how you would disciple such a low frequency at such a high
voltage and
>deliver the power required to drive several (or many) Clocks.
>
>I assume you would start with a commercially available UPS and either a
disciplined 1 Second 
>
>or 10Mhz source such as a thunderbolt (also powered off the UPS or the
batteries in the UPS).
>
>Does anyone have an suggestions for circuits which would do this
disciplining?
>
>Thanks
>Don
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