Surge protector? It will protect from a destructive surge, but afterwards may itself need to be replaced. Especially if it rattles.

Surge protectors don't monitor frequency and voltage disruptions. I think that these sometimes telegraph surges an are damaging in themselves. UPCs can condition power, but I don't ' need that sometimes. I just want to cut power when the.quality goes downhill.

A UPS is the only thing I can think of. And it would need to be one of the more expensive pure-sine wave types that use the invertor full time. That is, the line power runs a charger for the battery and an invertor provides the AC output for the load running off the charging battery. If the line fails, the invertor keeps going off the battery. The electronics decides when to switch to full battery based on low or high line voltage or frequency issues.

I guess that I need a broken PSW UPS (bad charger circuit or something). I won't need the batteries and I cut the connector to the Sonalert....

I'll keep looking. Maybe there is an OTS product for this somewhere.

You are asking for a relatively "intelligent" and complicated decision making capability for power management, which will not work well with a relatively dumb device (microwave, TV, etc.)

Most higher quality UPS's have the ability to monitor multiple power quality factors and report the status through a USB connection to a computer, so that part of your requirement is already taken care of. However, you then need a computer to accept the status information and make a decision, and then send the action request back to the UPS.

One possible solution would be a smart UPS monitoring combined with a Raspberry PI. The smart UPS would monitor power and gather statistics, and the PI (which probably runs Linux) would make the decisions and communicate back to the UPS.

Bruce

A power conditioner designed for home theater/audio use will monitor frequency and voltage. Actually if frequency changes there is a big problem, but voltage can swing quite a bit during peak loads and if a transformer fails etc. Something like an APC, Furman, etc. About the size of a component CD player or small receiver. They do cost a couple hundred bucks though and you can only plug so much stuff into one.

Thanks, it is really looking like what I'd like is not commercially available. Everything seems to be aimed at providing service as much as possible with no or short interruption. What I am really looking for is a divide to disconnect (in a pretty sensitive way) and not reconnect if power starts to go sour. If you abandon the support of continuous use and the need to restart, you no longer have to include batteries and a charger and cut complexity respectively. That would cut both initial cost and the cost of battery replacement not to mention decreasing the size and weight of the device by a great deal.

For something like a lot of home entertainment equipment, it seems ideal. If you are watching or listening, who needs automatic reconnection? You can just live with the dark screen and then push the reset button when you think that it is safe.

Note that I am thinking of monitoring voltage and frequency mostly as a signal that big problems (big surges) might be on the way.

Not much like a transfer switch. It should be for individual appliances or a small group of appliances. It does not need to reconnect, nor supply power. Ideally, it would have sensing capabilities much better than power drop-out (and surges). The ideal sensing capabilities would be high and low voltage and deviation from 60 Hz. I may be ill-informed, but I understand that disruptions to frequency are often harbingers of voltage surges, and connection-reconnection events.

This is possibly what you're looking for - http://hometheaterreview.com/monster-avs-2000-home-theater-voltage-stabilizer-reviewed/  Some reviewers aren't happy with it.

Unfortunately, that's not quite it either. All the stabilization capability puts the cost pretty high by my standards. I just want detection of problems and disconnect. I guess I am the only one that wants that.

Well, I think the folks who are looking for that are also looking for keeping their equipment powered up. Hence the functionality exists in better UPSs.