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

[J. Forster]

The cheapie inverters I've seen use a hgh frequency DC-DC cnverter to make
about 170 VDC, and then an H-bridge output stage, driven with a modified
square wave to make the AC.

Pretty crummy, IMO.

-John

==============



> 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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