Under / Over voltage protection.

[Crossy]

For those who only occasionally suffer from low voltage (< 170V) and want to avoid potential damage to motors etc. from attempting to start I found these :-

http://www.ebay.com/itm/261903753257?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

An all in one detector and contactor, no difficult wiring. Not adjustable but for the price one cannot be choosy, I've ordered a couple and will report once they arrive.

Now, if we could get them here ...

[bankruatsteve]

My problem is over voltage. I just had to get a new fridge (Samsung) to replace the Hitachi that has conked out twice now from over voltage. BTW: the new Samsung is a side-by-side inverter and so far really love it. But, when the voltage gets over about 240 it starts acting "funny" - like the face plate light will blink and it's like what am I supposed to do? That's when I switch over to genset and wait for voltage to drop.

So, the unit you show seems to have too large a range for me. I would like something from 195-245 V. The price seems right though.

Thanks for keeping us informed with your research!

[Mike45]

Have you found anything like this that is not din rail mounted for a sneider electric box?

[Crossy]

Have you found anything like this that is not din rail mounted for a sneider electric box?

Sadly no, the plug-in boxes (Schneider / Square-D, etc) don't support the useful devices.

It's not even easy to add up-front as you'll need over-current protection from a new incoming MCB (or Safe-T-Cut if you don't already have earth leakage protection).

[Bcgardener]

A company called Primus has a great range of protection devices. Google Primus Thailand. Their Web site is in English and has their full range of products plus technical data sheets

[Apache704]

I've been having voltage drop problems for 3 years now and it has caused me a lot of problems with some of my electrical appliances,fridge,water pump, computer etc. overheating. I had the electric company come to the house and checked out the voltage which happened to be 170 volts at the time. They said a new transformer was needed in the village as it was too small and would put in a request for a new one(6 months ago)and now was told maybe next year. It was getting worse every day especially at night and all I could have on was the lights,not having enough power to run other things especially the water pump. I was at my wits end until friend of mine told me about seeing Voltage stabilizers in Global House and that might solve my problem. I immediately went there and there were many to choose on depending on the amps you wanted. I bought a 45 amp Voltage stabilizer for 19,900 Baht(they also have 75 Amp and 100 Amp)brought it home and had it installed directly to the Main circuit breaker box. It has worked flawlessly since installed without any voltage drop whatsoever. I would recommend these stabilizers to anyone have these same kind of problems. There are also smaller ones that can have an appliance or two plugged into it. I hope that this information will help out anyone who has this similar problem. I posted this about 2 years ago and have had no problems with either under or over voltage since.

[IMHO]

If 5 Amps max. will do (or you can install a bigger relay/contactor as well), and you want something with programmable thresholds and break/connect time delays, these are readily available in Thailand:

http://www.wipelectric.com/product_desc.php?id_code=18

Known as a "Phase Protector" or "Phase Protection Relay" in Thailand.

[Naam]

My problem is over voltage ...

One of these http://www.ebay.co.uk/itm/Adjustable-Over-Under-Voltage-Protective-Relay-/221381033800?hash=item338b567f48:g:EMAAAOxyRhBSu1t9 hooked to a contactor in a DIN box will give you an adjustable solution.

$_57.JPG

Not cheap, but cheaper than a new fridge.

We have one controlling our generator start / transfer switch.

but much cheaper than a couple of burned pump or compressor starting relays. i wish i had that gadget years ago before i had my "monster" device installed.

question: any load limit?

[Crossy]

My problem is over voltage ...

One of these http://www.ebay.co.uk/itm/Adjustable-Over-Under-Voltage-Protective-Relay-/221381033800?hash=item338b567f48:g:EMAAAOxyRhBSu1t9 hooked to a contactor in a DIN box will give you an adjustable solution.

$_57.JPG

Not cheap, but cheaper than a new fridge.

We have one controlling our generator start / transfer switch.

but much cheaper than a couple of burned pump or compressor starting relays. i wish i had that gadget years ago before i had my "monster" device installed.

question: any load limit?

The relay in the unit itself is good for 5A, but use it to drive a contactor (giant relay) then the sky is the limit.

[Naam]

My problem is over voltage ...

One of these http://www.ebay.co.uk/itm/Adjustable-Over-Under-Voltage-Protective-Relay-/221381033800?hash=item338b567f48:g:EMAAAOxyRhBSu1t9 hooked to a contactor in a DIN box will give you an adjustable solution.

$_57.JPG

Not cheap, but cheaper than a new fridge.

We have one controlling our generator start / transfer switch.

but much cheaper than a couple of burned pump or compressor starting relays. i wish i had that gadget years ago before i had my "monster" device installed.

question: any load limit?

The relay in the unit itself is good for 5A, but use it to drive a contactor (giant relay) then the sky is the limit.

thanks Crossy, i thought as much.

[Crossy]

Just to update.

The beasts in the OP have arrived and seem to operate as advertised.

One thing to note is that despite being 2-units wide these only break the live pole so it is imperative that they are connected correctly. The same seller does some single-unit width ones but unless space is a real issue I wouldn't bother (they're more expensive).

I've had the lid off my spare unit and the build quality looks OK, decent 60A relay so no worries about things getting warm.

The unit I have currently installed is protecting the aircons which are not backed-up by the genset and so were exposed to the reduced supply voltage during periods of low supply.

EDIT There is an adjustment pot inside the unit, exactly what it adjusts is unknown at present, a job for when I can borrow a variac from work.

[RichCor]

EDIT There is an adjustment pot inside the unit, exactly what it adjusts is unknown at present, a job for when I can borrow a variac from work.

Couldn't you just connect it up to the Thai Grid, it does the same thing as a variac, just less predictably.

[Crossy]

EDIT There is an adjustment pot inside the unit, exactly what it adjusts is unknown at present, a job for when I can borrow a variac from work.

Couldn't you just connect it up to the Thai Grid, it does the same thing as a variac, just less predictably.

Our supply has been up around 240V for the last 24 hours. The calm before the storm?

Expect a dip to 150V or so tonight if it thinks about raining.

[Apache704]

I've been having voltage drop problems for 3 years now and it has caused me a lot of problems with some of my electrical appliances,fridge,water pump, computer etc. overheating. I had the electric company come to the house and checked out the voltage which happened to be 170 volts at the time. They said a new transformer was needed in the village as it was too small and would put in a request for a new one(6 months ago)and now was told maybe next year. It was getting worse every day especially at night and all I could have on was the lights,not having enough power to run other things especially the water pump. I was at my wits end until friend of mine told me about seeing Voltage stabilizers in Global House and that might solve my problem. I immediately went there and there were many to choose on depending on the amps you wanted. I bought a 45 amp Voltage stabilizer for 19,900 Baht(they also have 75 Amp and 100 Amp)brought it home and had it installed directly to the Main circuit breaker box. It has worked flawlessly since installed without any voltage drop whatsoever. I would recommend these stabilizers to anyone have these same kind of problems. There are also smaller ones that can have an appliance or two plugged into it. I hope that this information will help out anyone who has this similar problem. I posted this about 2 years ago and have had no problems with either under or over voltage since.