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 >>_______________________________________________ >>time-nuts mailing list -- [email protected] >>To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>and follow the instructions there. >> >>__________ Information from ESET Smart Security, version of virus > signature database 5851 (20110206) __________ >> >>The message was checked by ESET Smart Security. >> >>http://www.eset.com > > > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
