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

Chris Albertson albertson.chris at gmail.com
Sat Jun 25 18:55:43 UTC 2011


> The reason for using 12 Vdc, is that you can pick them up, and 24 Vac CT
> transformer, on the cheap

That's a good point.    So use two of them.  One to power a high
current amp that produces a 12V AC signal from a high precision 60Hz
input.  Then the other to convert the 12V to 120V.  This avoids the
need for a high voltage DC power supply.  Likely cuts the total cost
in half at least.     So just use use 12V supply to the amp and then a
cheap 12V transformer connected "backwards" to step up to the desired
voltage.

The second advantage of this design is that you can connect a lead
acid gell cell battery in parallel to the 12V DC supply and if the AC
fails the battery will power the amp for a while.   This way there is
no switching so the 60Hz wave remains continuously even if AC mains
fails.

This is something most UPS don't do but for this application you don't
want the  60Hz sine wave to be broken.

As long as the load is only a few milliamps of AC this should not be
hard to do.


-- 

Chris Albertson
Redondo Beach, California



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