Low-voltage protection

[desA]

We seem to have a number of occurrences of major voltage reduction, over extended periods.

An example was a period of at least 10 hours where line voltage measured at 187V, against the standard delivery of 220V.

The aircon systems (single phase) in my home couldn't even muster enough muscle to turn the evap fan properly, let alone the compressor.

I am looking for a cost-effective, simple way to shut down a heat-pump, or aircon system, when line voltage goes below an acceptable threshold & then either auto-set when it returns to the acceptable value, or have to be manually reset.

Thanks so much for your input.

[Yuri B.]

Hello. There are protective relays sensing voltage between neutral and each phase. Thera are two potentiometers on them with which you set the lower limit (let's say 210V) und the upper one. It has outputs - and I would feed through them a powerful contactor which would cut power to critical to undervoltage appliances. This is what first came to my mind. Such relay are rather expensive. Don not remember the name with which worked just recently.

[desA]

Thanks, Yuri.

Apologies - I should have added - its a single phase compressor, with low-load amps at around 6A & top-end amps at around 11A.

[lowcool]

pretty sure phasefale have one for single phase 240 volt 50 hz,your voltage & or hertz being different,one would think they have an application to suit.happy hunting

[desA]

^ Thanks very much, 'lowcool'.

[nike123]

Check page 9 here (http://www.global-download.schneider-electric.com/85257563005C526D/all/B2DD96B0400016B885256EDD00269608/$File/zeliotime__broc_en_200706.pdf)!

Model RM17 UBE 15

Must be used with contactor or power relay

[frank]

I have a brother who lives in Spain where line voltage varies considerably, often affected by the neighbour turning on the kettle!!

Since I sent himover one of these
http://www.apc.com/products/family/index.cfm?id=67
his problems have been much reduced.

From memory, I think this model adjusts for variations between 135V and 290V, giving out a constant 230V, although it's been some time since I read the spec sheet.

Have a good look around the APC web site - I'm sure you will find something that 'fit's the bill'

[nike123]

I have a brother who lives in Spain where line voltage varies considerably, often affected by the neighbour turning on the kettle!!

Since I sent himover one of these
http://www.apc.com/products/family/index.cfm?id=67
his problems have been much reduced.

From memory, I think this model adjusts for variations between 135V and 290V, giving out a constant 230V, although it's been some time since I read the spec sheet.

Have a good look around the APC web site - I'm sure you will find something that 'fit's the bill'

Is his unit inverter type?

[frank]

Yes it is, but his fridge, microwave, tv etc isn't.

if you purchase the correct size or multiple units, you can supply different pieces of equipment separately.