Ups

[janverbeem]

I'm into purchasing 3 UPS units 1000-1500 VA. As I know APC is the most renowned brand,I came across PCM at the IT-City and they said quality is good with 3 years warranty.Price is about 20% below APC for similar unit.

Anyone experience with PCM or other advises ?

I'm looking for the line interactive models.

[Tywais]

Normally I get APC. Have bought dozens for our lab and what I use at home. However, I did buy a Powercom (PCM) about 7-8 years ago when APC was a bit out of my budget and have put it on my media center computer and it is still running strong. One battery change during that time is all the maintenance I had done.

[janverbeem]

Normally I get APC. Have bought dozens for our lab and what I use at home. However, I did buy a Powercom (PCM) about 7-8 years ago when APC was a bit out of my budget and have put it on my media center computer and it is still running strong. One battery change during that time is all the maintenance I had done.

Thanks,that is the kind of info I was looking for.

[bobl]

I would not recommend APC their price does not warrant what you get out of them in terms of reliability (versus a cheaper UPS). However I also wouldn't recommend PCM from IT-City because their prices seem to be a bit $tupid...

I'm a bit confused why UPS's are so expensive here, I've also been sniffing around with a view to buying a couple. But the price of a 1.5kVA line interactive at the likes of IT-City is about what I expected to be paying for a 3kVA ONLINE ups, based on my experience...

I lived in Tanzania for 16 years where the power is pretty horrible, so have fairly extensive experience with all types of UPS. I'm not sure why you want Line Interactive as opposed to online - online is a far better choice.

In Africa I was paying (roughly) $130 for a 2kVA offline (line interactive) and $360 for a 3kVA online. I'm currently looking for suppliers other than the "IT Superstores" at similar prices. Failing that maybe I'll import a few...

Edited December 2, 2011 by bobl

[janverbeem]

I prefer Line interactive as I understand that this is a cheaper option for electricity costs since the online uses electricity continiously as the power always goes through the ups and is converted.

Let me know if you find something at Tanzania prices.

[Tywais]

I would not recommend APC their price does not warrant what you get out of them in terms of reliability (versus a cheaper UPS).

Have to disagree with that. I have probably 50 APC UPSes at work and a few cheap units that got by me during purchases (I approve computer related purchases). Most of the cheaper units blow up with a sufficient power surge and the APC very rarely fail. APC prices have come in line price wise considerably over the last couple of years and more competitive.

You pay a hefty premium for the on-line, especially true sine, over line-interactive which for computer back up I don't feel is warranted. We do have a PCM 15kVA UPS true sine, on-line with 16 batteries on it - 300,000 Baht. But it does backup a 20 million baht piece of equipment.

[BangkokImages]

UPS devices have a bit more going on under the hood than most give them credit for.

And most brands are not created equal even if built to the same specs. The quality of components is critical with anything to do with a power supply.

Most of your cheaper UPS devices don't provide a true sine wave. Instead, they give you a square wave which is cheaper to produce, but not what you're equipment was designed to operate on.

"Surges" is just one area you should expect a UPS to protect from. The ability to soak up a surge is rated in "joules" , the more the better.

In Thailand surges aren't your main problem. Brownouts are your main problem you want protection from. Brownouts occur when the voltage drops below it's rating. The quality of the computer (or other protected device), or rather the quality of the power supply in the computer.. determines exactly (as the voltage drops) where you'll start experiencing issues.

Brownouts are a problem because in general electricity is poorly regulated. "Poorly" is being generous. There is also the issue of single and three phase power. Single phase power works a bit like an old string of xmas lights. Power goes in one end and is fed bulb to bulb in series. If one bulb goes out, all bulbs after the failed bulb go out as well. In rural Thai areas, even some inner city areas, you have single phase power. You have a transformer on a pole with a single line feeding first one house, then the next, and then the next, and so on. If you live in house 5 and house 3's big AC turns on.. you're voltage will drop (a lot) and take a lot of time to stabilize back up. If you live in house 5, and house 1, 2, 3, and 4 are using power in the busy time.. it will never stabilize to normal It drops and stays down. Three phase power is what you're used to in the west.. it's like new xmas lights. They work in parallel. One bulb goes out, the others keep working. In a neighborhood 3 phase power will have three physical lines. A ground, main power, and return.. and three phase is very quick to stabilize.

Normally you would be correct to think you'd need less brownout protection if you had three phase power. But in Thailand power is so poorly regulated, lines are in such bad condition, etc, etc.. it's bad all the time.

There is also the time it takes for a UPS to react. This time should be in the microseconds.. but with cheaper units is in the milliseconds. A millisecond is a world of time to cause damage to your computer.

Control of your computer during unattended shutdown and the associated software is important and adds value too.

When you look at it all closely.. APC server grade UPS devices are one of the few (Tripp Light, APC, and lately Cyber Power) which offers true protection. There are a bunch of smaller local companies who make products that call themselves UPS devices, and they even look like one. They just don't function like one once you look under the hood. I'm not that fond of some of APC's consumer grade UPS devices either.

Server grade UPS devices re normally pricey. In the states there is a company who is contracted by APC to sell all their refurbs and obsolete product.. these are often 20-30% of a new one. I've ran them for years and an running them now.

[Crossy]

Much of the above post is good advice.

However the description of single and 3-phase power is flawed to say the least, so just ignore those bits

[BangkokImages]

Much of the above post is good advice.

However the description of single and 3-phase power is flawed to say the least, so just ignore those bits

Please feel free to improve or change the explanation. Curious minds want to know.

[Tywais]

A couple of clarification points. 1st brownouts - this is one of the main differences between standby and line-interactive UPSes. A line interactive is meant to handle brownouts and does it by auto-switching taps on the transformer. If the voltage drops it boosts the transformer output by switching taps and vice-versa.

As for most cheaper units not supplying true sine-wave, actually the majority of standby and line-interactive do not supply true sine wave but pseudo sinewave and it is not a square wave that is on the final output as it runs through an LC filter to smooth the square wave out.

There is also the time it takes for a UPS to react. This time should be in the microseconds.. but with cheaper units is in the milliseconds. A millisecond is a world of time to cause damage to your computer.

Switch over time - All PC computer power supplies are SMPS (switch mode) and both inherently and by standards are required to not have the DC output effected by a minimum of 10 mSecs. As such, the microsecond switch over is not a requirement for the majority of items running from SMPS.

[BangkokImages]

A couple of clarification points. 1st brownouts - this is one of the main differences between standby and line-interactive UPSes. A line interactive is meant to handle brownouts and does it by auto-switching taps on the transformer. If the voltage drops it boosts the transformer output by switching taps and vice-versa.

As for most cheaper units not supplying true sine-wave, actually the majority of standby and line-interactive do not supply true sine wave but pseudo sinewave and it is not a square wave that is on the final output as it runs through an LC filter to smooth the square wave out.

There is also the time it takes for a UPS to react. This time should be in the microseconds.. but with cheaper units is in the milliseconds. A millisecond is a world of time to cause damage to your computer.

Switch over time - All PC computer power supplies are SMPS (switch mode) and both inherently and by standards are required to not have the DC output effected by a minimum of 10 mSecs. As such, the microsecond switch over is not a requirement for the majority of items running from SMPS.

a. Yes, this is how it works. They do this to save wear and tear on the battery.. new tech isn't always best.

b. The majority of UPS devices aren't the higher quality devices we're led to believe. Server class UPS devices, at least the better brands, do output a pure sine wave.

c. True, but does every device you use on your UPS have a SMPS? Monitors for instance. What about your network equipment run by simple converters? NAS devices? I run UPS devices (5) for more than my PC box and while some of my devices will keep on working despite a slow correction, it still puts wear and tear on them. If you can utilize the refurb stores and get server class UPS's for the same cost as new consumer grade.. I'd recommend you do. It's more about long term reliability than immediate fault correction, which is why servers have tougher requirements.

[InterestedObserver]

The primary difference between single and three phase electrical power has to do with how it is generated and transmitted/distributed. In easy to understand terms, a three-phase generator has 3 x single-phase windings distributed 120 electrical degrees around the generator structure. It is much more efficient to sent this electrical power out using three wires instead of the six wires (remember the generator has three separate windings) that would be necessary using single-phase. At your local transformer the single-phase is extracted from the generated three-phase and distributed to your home usually using 2 single-phase wires. All houses and household loads are connected in parallel. The only difference being the voltage drop, starting at the transformer, that is sustained while traversing the length of the distribution circuit. To mitigate voltage drop and service interruption, some large houses will bring in all three phases for use.

[BangkokImages]

The primary difference between single and three phase electrical power has to do with how it is generated and transmitted/distributed. In easy to understand terms, a three-phase generator has 3 x single-phase windings distributed 120 electrical degrees around the generator structure. It is much more efficient to sent this electrical power out using three wires instead of the six wires (remember the generator has three separate windings) that would be necessary using single-phase. At your local transformer the single-phase is extracted from the generated three-phase and distributed to your home usually using 2 single-phase wires. All houses and household loads are connected in parallel. The only difference being the voltage drop, starting at the transformer, that is sustained while traversing the length of the distribution circuit. To mitigate voltage drop and service interruption, some large houses will bring in all three phases for use.

Thank you. I realize I was stretching things a bit (okay, a lot) with the xmas light explanation.. Maybe it would be better to explain it the way it was explained to me locally by a Thai power company engineer (while investigating issues at an estate in Hua hin of baht 25m homes where they were having a hard time keeping anything with a microprocessor alive past a few weeks). Using your explanation as a reference, those two wires were being shared by up to ten homes. This is commonly done in rural areas to save the cost of running lines. And in this case, and I'm told in many others, the two wires were run along poles and tapped into by each house without a completion of the loop at the end of the soi. What should have been done was to run 3-phase down the entire soi at I think 380v? And take off the 220 single phase at each home site. What this does is create severe drops, more severe when more people are at home. I was told this was common in Thailand, less so in the cities, but for sure in small groups of houses or single sois in the country. In the case of the contractor who built this estate complex (a Brit contractor) and marketed the homes, he claims he wasn't told this was being done, that the electric company charged him the correct fees and then set things up like this to save money.

[Tywais]

Switch over time - All PC computer power supplies are SMPS (switch mode) and both inherently and by standards are required to not have the DC output effected by a minimum of 10 mSecs. As such, the microsecond switch over is not a requirement for the majority of items running from SMPS.

c. True, but does every device you use on your UPS have a SMPS? Monitors for instance.

You misread my post - I was referring only to devices running from SMPS but even then no guarantee they are built according to industry standard dropout timing - cheap Chinese SMPS powered units come to mind and why I mentioned 'majority'. Pretty much all modern LCD monitors do employ SMPS, either those powered internally or via wall warts. Those wall adapters for printers, scanners, etc. are a mixed bag and may be SMPS and may be linear (analog). Usually tell by the size and how hot they get.

//edit - actually linear (analog) power supplies can also handle long ms dropouts depending on the storage capacitance. I designed a unit that ran for a few minutes after pulling the power cord out.

[BangkokImages]

You misread my post - I was referring only to devices running from SMPS but even then no guarantee they are built according to industry standard dropout timing - cheap Chinese SMPS powered units come to mind and why I mentioned 'majority'. Pretty much all modern LCD monitors do employ SMPS, either those powered internally or via wall warts. Those wall adapters for printers, scanners, etc. are a mixed bag and may be SMPS and may be linear (analog). Usually tell by the size and how hot they get.

//edit - actually linear (analog) power supplies can also handle long ms dropouts depending on the storage capacitance. I designed a unit that ran for a few minutes after pulling the power cord out.

It's always difficult when discussing this stuff because there's very little you don't need to qualify with "majority" or "most of.."

Cheap power supplies are more the rule than the exception. Many monitors, especially the new LED backlit 16:9 variety, have cheap adapters too. Camera equipment also comes to mind.

I'd much rather have a fast switching UPS..

[bobl]

I prefer Line interactive as I understand that this is a cheaper option for electricity costs since the online uses electricity continiously as the power always goes through the ups and is converted.

Not exactly. A line Interactive UPS feeds your equipment directly from utility power (usually via AVR circuitry) while at the same time keeping the battery "trickle charged", and switches over to battery in the event of a failure of input power. When power comes back, it reverts to feeding you directly from utility power (whilst re-charging until full, then trickle charging the battery) ready for the next power cut.

An online UPS has 2 major differences. First, they are typically at least a modified sine wave output, with the more expensive ones being a true sine wave. On the other hand line interactive tend to be (when running on battery power) a square wave or at best a modified sine wave.

The second major difference is that an online UPS's output is generated permanently from DC power. Such UPS's are also sometimes referred to as "double conversion" UPS's. Utility power is converted to DC which is used to both keep the battery charged, and provide DC to the DC to AC inverter that supplied your 220Vac. Basically the inverter - the part which converts DC back to AC - has two sources of DC power - converted utility power, and the battery. If utility power fails it continues running off the battery. That is why there is zero changeover time on an online UPS, whilst line interactive will have a changeover time of anything from a few hundred microseconds to tens of milliseconds depending on quality.

That's the long answer. The short answer is that an online UPS will use little or no more power than a line interactive UPS. They both use a minimal amount of electricity keeping the battery trickle charged, otherwise your power consumption depends almost entirely on your load.

Let me know if you find something at Tanzania prices.

Will do... Still hunting...

[BB1950]

The primary difference between single and three phase electrical power has to do with how it is generated and transmitted/distributed. In easy to understand terms, a three-phase generator has 3 x single-phase windings distributed 120 electrical degrees around the generator structure. It is much more efficient to sent this electrical power out using three wires instead of the six wires (remember the generator has three separate windings) that would be necessary using single-phase. At your local transformer the single-phase is extracted from the generated three-phase and distributed to your home usually using 2 single-phase wires. All houses and household loads are connected in parallel. The only difference being the voltage drop, starting at the transformer, that is sustained while traversing the length of the distribution circuit. To mitigate voltage drop and service interruption, some large houses will bring in all three phases for use.

Much of the information you provided is not quite correct.

Typical 3 phase distribution in Thailand is 3 phase star ( or Wye) which uses 4 wires (3 hot wires and 1 neutral).

With this 3 phase distribution system (which is supplied to businesses and larger homes), there are three hot wires with each being 120 degrees out of phase with each other. The voltage potential is approximately 400 volts between each hot wire. The voltage potential between any of the hot wires and the neutral is approximately 240 volts.

Single phase power (supplied to smaller homes) uses 2 wires (one hot wire and the neutral wire). Two phase power in Thailand (supplied to medium sized homes) uses 3 wires (2 hot wires and the neutral wire). Many times there is a misunderstanding about this because some countries like the U.S., the 2 phase power is actually a 'split phase'. The two hot wires on a 'split phase' are 180 degrees out of phase, rather than being 120 degrees out of phase.

Three-phase power can be more efficient than single-phase power in certain applications. Three-phase motors, for example, are much more powerful (or efficient) than their single-phase counterparts. And three-phase motors are cheaper because they are less complex and do not require starting capacitors.

Here is a good analogy which should help you visualize the differences between single phase and three phase: Using a single-phase supply is like one strong man pushing a car uphill. At some point, the work is beyond what that one man can do; whereas a three-phase supply is like having three equally strong men each pushing the car in a relay system one after another. The end result is that each man is doing 1/3 the work of the one strong man so, together, the three of them push the car further. Or, you can think of it like this: In Thailand., our power is generated at 50 Hz. So, a single-phase circuit's sine wave will swing +/- at a rate of 50 times per second. Think of it as 50 "pulses" or "pushes" of work per second. A three-phase circuit combines three single-phase circuits (each 120 degrees out of sync with the other) so in the same one second period of time you've got three "pulses" or "pushes" ... or three times the work!

I hope this helps clear up any confusion.

I'm a bit puzzled why this thread even discussing a 3 phase UPS (because of the limited battery life of a UPS). You are talking about an extremely expensive industrial application!

Edited December 3, 2011 by BB1950

[Gary A]

My first UPS was a small Socomet. It finally gave up and I bought a much larger Ablerex. The local dealer I bought the Socomet from had in the meantime put a new battery in the Socomet and it still works fine. I use both. The original battery was six years old. The much newer Ablerex has two batteries and they are still the originals.

I actually ordered an APC but it was not available and I didn't want to go without a UPS. Due to the very good performance of both my units, I see no reason to struggle to find a more popular brand.

[BB1950]

Thank you. I realize I was stretching things a bit (okay, a lot) with the xmas light explanation.. Maybe it would be better to explain it the way it was explained to me locally by a Thai power company engineer (while investigating issues at an estate in Hua hin of baht 25m homes where they were having a hard time keeping anything with a microprocessor alive past a few weeks). Using your explanation as a reference, those two wires were being shared by up to ten homes. This is commonly done in rural areas to save the cost of running lines. And in this case, and I'm told in many others, the two wires were run along poles and tapped into by each house without a completion of the loop at the end of the soi. What should have been done was to run 3-phase down the entire soi at I think 380v? And take off the 220 single phase at each home site. What this does is create severe drops, more severe when more people are at home. I was told this was common in Thailand, less so in the cities, but for sure in small groups of houses or single sois in the country. In the case of the contractor who built this estate complex (a Brit contractor) and marketed the homes, he claims he wasn't told this was being done, that the electric company charged him the correct fees and then set things up like this to save money.

Let me try to clarify this.

This is commonly done in rural areas to save the cost of running lines. And in this case, and I'm told in many others, the two wires were run along poles and tapped into by each house

Yes, this is correct. But I'm not sure what you meant by this:

without a completion of the loop at the end of the soi.

There's usually no completion of the loop at the end of the soi in rural areas. It's not really a loop, more like a branch from the transformer. However in some cases where there may be a loop to help offset the drops due to line loses. For example in a very small village.

What should have been done was to run 3-phase down the entire soi at I think 380v? And take off the 220 single phase at each home site. What this does is create severe drops, more severe when more people are at home. I was told this was common in Thailand, less so in the cities, but for sure in small groups of houses or single sois in the country.

This is true and is is done in the non rural areas.It is to balance the load on the transformers. The transmission lines do have have resistance, so there are voltage drops due to increased load and distance.

Note: There was only a two wires running down my Soi in Huai Yai from the beginning of the Soi supplying 220v single phase power to the Thai houses along the Soi. Because my house is large (with 6 air conditioners), I had to run the extra 2 wires (when building the house) from the transformer (at the entrance of the Soi) to the house. With only single phase supply there would have been a severe voltage drop.

I hope this helps.

Edited December 3, 2011 by BB1950

[InterestedObserver]

The primary difference between single and three phase electrical power has to do with how it is generated and transmitted/distributed. In easy to understand terms, a three-phase generator has 3 x single-phase windings distributed 120 electrical degrees around the generator structure. It is much more efficient to sent this electrical power out using three wires instead of the six wires (remember the generator has three separate windings) that would be necessary using single-phase. At your local transformer the single-phase is extracted from the generated three-phase and distributed to your home usually using 2 single-phase wires. All houses and household loads are connected in parallel. The only difference being the voltage drop, starting at the transformer, that is sustained while traversing the length of the distribution circuit. To mitigate voltage drop and service interruption, some large houses will bring in all three phases for use.

Much of the information you provided is not quite correct.

Typical 3 phase distribution in Thailand is 3 phase star ( or Wye) which uses 4 wires (3 hot wires and 1 neutral).

With this 3 phase distribution system (which is supplied to businesses and larger homes), there are three hot wires with each being 120 degrees out of phase with each other. The voltage potential is approximately 400 volts between each hot wire. The voltage potential between any of the hot wires and the neutral is approximately 240 volts.

Single phase power (supplied to smaller homes) uses 2 wires (one hot wire and the neutral wire). Two phase power in Thailand (supplied to medium sized homes) uses 3 wires (2 hot wires and the neutral wire). Many times there is a misunderstanding about this because some countries like the U.S., the 2 phase power is actually a 'split phase'. The two hot wires on a 'split phase' are 180 degrees out of phase, rather than being 120 degrees out of phase.

Three-phase power can be more efficient than single-phase power in certain applications. Three-phase motors, for example, are much more powerful (or efficient) than their single-phase counterparts. And three-phase motors are cheaper because they are less complex and do not require starting capacitors.

Here is a good analogy which should help you visualize the differences between single phase and three phase: Using a single-phase supply is like one strong man pushing a car uphill. At some point, the work is beyond what that one man can do; whereas a three-phase supply is like having three equally strong men each pushing the car in a relay system one after another. The end result is that each man is doing 1/3 the work of the one strong man so, together, the three of them push the car further. Or, you can think of it like this: In Thailand., our power is generated at 50 Hz. So, a single-phase circuit's sine wave will swing +/- at a rate of 50 times per second. Think of it as 50 "pulses" or "pushes" of work per second. A three-phase circuit combines three single-phase circuits (each 120 degrees out of sync with the other) so in the same one second period of time you've got three "pulses" or "pushes" ... or three times the work!

I hope this helps clear up any confusion.

I'm a bit puzzled why this thread even discussing a 3 phase UPS (because of the limited battery life of a UPS). You are talking about an extremely expensive industrial application!

1. Look way up on the top of the PEA distribution poles and you will see three wires carrying the three-phase power, not four wires. The neutral is not run, to save money, although there are a few exceptions. The source is a star (wye) connection.

2. The secondary, after the local transformer, will usually carry the fourth neutral wire so 380Y/220V can be accessed for 220V residential use.

3. There is no such thing as two-phase power in modern electrical power systems. Two-phase power is characterized by a 90 degree phase displacement, not 120 or 180 degrees. Google: Two-phase electric power.

4. We are talking residential (home) usage. Nobody mentioned three-phase electric motors. You can get single-phase electric motors up to approximately 10+ HP that do the same amount of work as a similar rated three-phase motor, with the same efficiency.

5. Work is work. The amount of work done in joules (J) or watts (J/second) does not change if you replace a single-phase motor with a three-phase motor. It requires the same amount of work to push the car up the hill.

[Gary A]

I have no idea how my units work and really don't care. All I know is that when the crappy power supply is over voltage or under voltage, both are clicking and both start beeping. My computer has never shut down. As far as I am concerned, they do the job that I bought them to do. I do have a cheap surge protector between the UPS's and the equipment. Will the surge protector work and is it any good? I have no idea but it wasn't much more expensive than a simple multi-outlet adapter.

[BangkokImages]

I have no idea how my units work and really don't care. All I know is that when the crappy power supply is over voltage or under voltage, both are clicking and both start beeping. My computer has never shut down. As far as I am concerned, they do the job that I bought them to do. I do have a cheap surge protector between the UPS's and the equipment. Will the surge protector work and is it any good? I have no idea but it wasn't much more expensive than a simple multi-outlet adapter.

a. LOL! This is typical of the vast majority of consumers. This is why it's so easy for the small manufacturers to put out inexpensive products which look and feel like the real thing, but might not be your best choice.

b. Your computer not shutting down is part of what it's supposed to do, but if it's knocking years of life off your components or letting through transient spikes which could cause a board/memory module/etc to fail, but often causes minor damage which manifests itself in 'glitches' that annoy the hell out of you, then it might not be the best choice. I think bottom line is that if you're getting the life expectancy and performance you require out of your gear.. then you're doing fine.

This has been a good discussion. I think the three/single phase thing understandable got a bit mixed up, I was talking strictly in neighborhood distribution system vs. actual 3 phase applications like electric motors.. but it was all good information nonetheless.

In my mind here's the thing. Heat and bad/erratic/crappy power are the two major causes of electronics failure. Often they're related. If you buy a $500 computer than a cut rate UPS is probably appropriate. But if you're spending $1500-$3000 or more for a great new computer system, then it pays to maximize your investment and enjoyment of that investment by properly protecting it.

And in the realm of UPS devices there are significant differences. Power distribution differences create an unequal playing field, just because a cut rate UPS worked well in one location doesn't mean it will work well in another. It pays to have a basic understanding of what you're working with and make choices accordingly. If you call your local Thai electric company engineers out they will (usually) put a monitor on your line and explain to you if there are any issues in your local distribution system, what time of day it might be the most problem, and if anything can be done about it.. which there usually isn't short of expensive options.

I think many of you would be shocked (pardon the pun) to see the tape from the load monitor. We're not talking spikes or low voltages every now and then, but rather a constant most every minute variation of some kind. Thailand has the dirtiest power I've seen anywhere. Your computer by itself might handle this, or it might be incurring damage as it does and the lifespan is greatly shortened.

A cu trate UPS might protect it from outages, but without grounds in most Thai homes any serious surges will get through. They also don't protect much against the most common/serious issue which is brownouts. In contrast, a good brand server class UPS will provide constant clean power to your electronics. These are expensive, but through a refurb program the cost can be brought down to consumer grade UPS costs or less. I recently purchased 5 server class UPS devices, 3 1500's, 1 650, 1 620.. for under $600 through this company. Possibly they have one like it in Thailand but I was never able to find it.

[janverbeem]

I have no idea how my units work and really don't care. All I know is that when the crappy power supply is over voltage or under voltage, both are clicking and both start beeping. My computer has never shut down. As far as I am concerned, they do the job that I bought them to do. I do have a cheap surge protector between the UPS's and the equipment. Will the surge protector work and is it any good? I have no idea but it wasn't much more expensive than a simple multi-outlet adapter.

a. LOL! This is typical of the vast majority of consumers. This is why it's so easy for the small manufacturers to put out inexpensive products which look and feel like the real thing, but might not be your best choice.

b. Your computer not shutting down is part of what it's supposed to do, but if it's knocking years of life off your components or letting through transient spikes which could cause a board/memory module/etc to fail, but often causes minor damage which manifests itself in 'glitches' that annoy the hell out of you, then it might not be the best choice. I think bottom line is that if you're getting the life expectancy and performance you require out of your gear.. then you're doing fine.

This has been a good discussion. I think the three/single phase thing understandable got a bit mixed up, I was talking strictly in neighborhood distribution system vs. actual 3 phase applications like electric motors.. but it was all good information nonetheless.

In my mind here's the thing. Heat and bad/erratic/crappy power are the two major causes of electronics failure. Often they're related. If you buy a $500 computer than a cut rate UPS is probably appropriate. But if you're spending $1500-$3000 or more for a great new computer system, then it pays to maximize your investment and enjoyment of that investment by properly protecting it.

And in the realm of UPS devices there are significant differences. Power distribution differences create an unequal playing field, just because a cut rate UPS worked well in one location doesn't mean it will work well in another. It pays to have a basic understanding of what you're working with and make choices accordingly. If you call your local Thai electric company engineers out they will (usually) put a monitor on your line and explain to you if there are any issues in your local distribution system, what time of day it might be the most problem, and if anything can be done about it.. which there usually isn't short of expensive options.

I think many of you would be shocked (pardon the pun) to see the tape from the load monitor. We're not talking spikes or low voltages every now and then, but rather a constant most every minute variation of some kind. Thailand has the dirtiest power I've seen anywhere. Your computer by itself might handle this, or it might be incurring damage as it does and the lifespan is greatly shortened.

A cu trate UPS might protect it from outages, but without grounds in most Thai homes any serious surges will get through. They also don't protect much against the most common/serious issue which is brownouts. In contrast, a good brand server class UPS will provide constant clean power to your electronics. These are expensive, but through a refurb program the cost can be brought down to consumer grade UPS costs or less. I recently purchased 5 server class UPS devices, 3 1500's, 1 650, 1 620.. for under $600 through this company. Possibly they have one like it in Thailand but I was never able to find it.

And how do you get them in Bangkok.How about customs?

[JSixpack]

Most of us aren't going to pay $600 for a (used) server-grade UPS. I won't, though I'd be willing to believe a $600 UPS would be better than a $100 UPS, yes.

Well, I don't see any hard measurements & numbers here comparing the different brands as the OP was asking. That leaves us with anecdotes. OK, I've had a cheap Thai UPS that was crap; never again. I've had an APC and it was good until it corroded out after a few years. I've had two PCMs now for about 4-5 years, changed out the battery in the older one, and they've both been great through the years of brownouts and blackouts and I suppose surges. I have one computer on throughout the day every day.

I had checked the reviews before I bought and found that PCM is well-regarded in its class. I would buy PCM again.

[BangkokImages]

And how do you get them in Bangkok.How about customs?

This is the big problem and why I'm hoping someone knows where the refurbs are being sold locally in Thailand. There must be a place.

As far as ones from the states.. server grade UPS devices are heavy, 30-35kg's easy.. so paying for shipping on just one would be $300 or so. I'd guess this isn't economically viable.. and besides, the voltages would be different and would require the use of a transformer.

Certainly there is a place to buy new ones, but I keep hoping someone turns up a refurb place in one of these threads someday.

[BangkokImages]

Most of us aren't going to pay $600 for a (used) server-grade UPS. I won't, though I'd be willing to believe a $600 UPS would be better than a $100 UPS, yes.

Well, I don't see any hard measurements & numbers here comparing the different brands as the OP was asking. That leaves us with anecdotes. OK, I've had a cheap Thai UPS that was crap; never again. I've had an APC and it was good until it corroded out after a few years. I've had two PCMs now for about 4-5 years, changed out the battery in the older one, and they've both been great through the years of brownouts and blackouts and I suppose surges. I have one computer on throughout the day every day.

I had checked the reviews before I bought and found that PCM is well-regarded in its class. I would buy PCM again.

a. The $600 I quoted was for 5 server grade UPS devices.

b, We have a lot more than anecdotes. Using the information in this thread anyone is capable of looking at specifications and putting the pieces together for themselves. There's also google, it doesn't take long to learn a lot about UPS's with a bit of research. Specifications are useful, and if a company doesn't list a specification on a critical spec.. then that should be all you need to know. Reviews as you mentioned can be useful as well.

[BB1950]

1. Look way up on the top of the PEA distribution poles and you will see three wires carrying the three-phase power, not four wires. The neutral is not run, to save money, although there are a few exceptions. The source is a star (wye) connection.

2. The secondary, after the local transformer, will usually carry the fourth neutral wire so 380Y/220V can be accessed for 220V residential use.

3. There is no such thing as two-phase power in modern electrical power systems. Two-phase power is characterized by a 90 degree phase displacement, not 120 or 180 degrees. Google: Two-phase electric power.

4. We are talking residential (home) usage. Nobody mentioned three-phase electric motors. You can get single-phase electric motors up to approximately 10+ HP that do the same amount of work as a similar rated three-phase motor, with the same efficiency.

5. Work is work. The amount of work done in joules (J) or watts (J/second) does not change if you replace a single-phase motor with a three-phase motor. It requires the same amount of work to push the car up the hill.

"1. Look way up on the top of the PEA distribution poles and you will see three wires carrying the three-phase power, not four wires. The neutral is not run, to save money, although there are a few exceptions. The source is a star (wye) connection."

Most of the time I have seen all four wires. The fourth wire (neutral) wire usually is an uninsulated ground wire (for lightning protection).

Recently I have been seeing PEA upgrading the distribution system using insulated cables separated within a rectangular bracket which has a fifth uninsulated ground wire. I'm told that in the center of these cables is a fiber optic cable that will eventually provide internet, TV, and phone services throughout Thailand.

"3. There is no such thing as two-phase power in modern electrical power systems. Two-phase power is characterized by a 90 degree phase displacement, not 120 or 180 degrees. Google: Two-phase electric power."

Correct there is no two-phase with a 90 degree phase displacement. But in the US there is the 'split phase' with a 180 phase displacement that is referred to by most as two-phase, used in most residences. Here in Thailand, PEA supplies some residences with what they call two-phase, which is two legs of the three phase. My previous home in Jomtien had it.

"4. We are talking residential (home) usage. Nobody mentioned three-phase electric motors. You can get single-phase electric motors up to approximately 10+ HP that do the same amount of work as a similar rated three-phase motor, with the same efficiency.

5. Work is work. The amount of work done in joules (J) or watts (J/second) does not change if you replace a single-phase motor with a three-phase motor. It requires the same amount of work to push the car up the hill."

Yes, we are talking about residential home usage in Thailand. I supplied the analogy to help others understand the principles behind 3-phase. You were incorrect by your previous statement:

"All houses and household loads are connected in parallel."

The three-phase supplied to homes and businesses in Thailand are the same.

Yes, you can get large single phase motors. But they aren't as efficient because they require larger wiring and more energy is lost in heat. Three-phase motors are lighter, smaller, and more efficient. As a result, they cost less to buy and operated. They also use smaller wiring to supply them.

The reason for the analogy. One of the largest demands for energy in a household is air conditioners. There are 3-phase units for home use in larger rooms. Some homes in Thailand even have central air. The three-phase units are more efficient because energy is not lost by heat.

[BB1950]

In my mind here's the thing. Heat and bad/erratic/crappy power are the two major causes of electronics failure. Often they're related. If you buy a $500 computer than a cut rate UPS is probably appropriate. But if you're spending $1500-$3000 or more for a great new computer system, then it pays to maximize your investment and enjoyment of that investment by properly protecting it.

And in the realm of UPS devices there are significant differences. Power distribution differences create an unequal playing field, just because a cut rate UPS worked well in one location doesn't mean it will work well in another. It pays to have a basic understanding of what you're working with and make choices accordingly. If you call your local Thai electric company engineers out they will (usually) put a monitor on your line and explain to you if there are any issues in your local distribution system, what time of day it might be the most problem, and if anything can be done about it.. which there usually isn't short of expensive options.

I think many of you would be shocked (pardon the pun) to see the tape from the load monitor. We're not talking spikes or low voltages every now and then, but rather a constant most every minute variation of some kind. Thailand has the dirtiest power I've seen anywhere. Your computer by itself might handle this, or it might be incurring damage as it does and the lifespan is greatly shortened.

A cu trate UPS might protect it from outages, but without grounds in most Thai homes any serious surges will get through. They also don't protect much against the most common/serious issue which is brownouts. In contrast, a good brand server class UPS will provide constant clean power to your electronics.

So very true.

I live in a rural area and we frequently suffer from brownouts and lightning strikes.

Once we had a direct lightning strike which blew-up the electric meter and set the distribution wires to the meter on fire. It was similar to roman candle fireworks. A couple weeks after the strike, I noticed that I was having to replace light bulbs far too frequently (every few days), so I checked the voltage at the distribution panel. Alarmingly, it was 696 volts across each leg of the three-phase supply and 493 volts for each of the phase to neutral legs. I immediately turned off the mains and contacted PEA. The sent a technician immediately to the house. He was here within 15 minutes. He also was very surprised, They immediately replaced the transformer at the entrance of the Soi. Turns out the lightning strike had also damaged the transformer.

Several times since we have had several lightning strikes which caused electronic neon light fixtures to blow up and electrically to arc across the outlets. I've lost track of the number, but far too many.

I attribute my high quality APC UPS (3000 baht 8 years ago) along with an excellent properly wired earth ground as saving my computer equipment in each instance. However much of my other electronic equipment (connected though surge protectors) have not survive.

I stand 100% behind a good quality UPS along with properly grounded outlets.. It's a small investment compared to the damage that could have been done.

I have a friend who bought a couple cheap UPSs (1400 baht). His computer equipment and UPS did not survive a recent lightning strike. Afterwards, I checked the power at the outlet and also discovered that the outlet had incorrect phasing (neutral and hot wire reversed), but he did have a good earth. This possibly could have contributed to the failures.

Can you afford to take a chance? He decided not. He had a knowledgeable electrician check all his outlets and they all were incorrect. They were all rewired and he purchased a much better UPS.

There's an old saying, "You pay one way or another". You decide which is better.

I feel it's "better to be safe than sorry".

[Tywais]

Once we had a direct lightning strike which blew-up the electric meter and set the distribution wires to the meter on fire. It was similar to roman candle fireworks. A couple weeks after the strike, I noticed that I was having to replace light bulbs far too frequently (every few days), so I checked the voltage at the distribution panel.

A recent experience of mine. A few weeks ago I was in my office and kept hearing some popping sounds like sparks. Couldn't locate it as it was intermittent. It then got more noticeable and the florescent lights were misbehaving. Shortly all power went off. I suspected a loss in one of the phases that started it and one of our technicians was quick enough to shut the mains off to the building.

I went down to check the incoming line voltages (380 3 phase) and they were messed up. One phase missing and the others wrong reading but was getting no 3 phase to neutral readings (220). Power people came and found a fuse at the pole transformer blown so that explained the missing phase and miss balance in the others. Still no 3 phase to neutral readings at the bus bars. Checked it at the top of the building and ok. There was a 2 meter splice inside the mains cabinet from the neutral to the bus bar. Above the splice ok, below nothing. This is not a small type of splice but a massive aluminum splice as the wire is aluminum and the wire about 2 cm diameter and hydraulics are used to clamp the splice on. They put on a new, heavier duty splice and that fixed it. These were put in over 25 years ago and this power distribution is for a large research building with significant power loads.

Anyway, had to start accessing damage and it was pretty significant. You could smell burning electrics/electronics throughout the building. Probably 20% of the electronic ballasts for the fluorescent lights were damaged, several control boards in air conditioners damaged, many wall adapters for things like printers, scanners, wifi access points etc including 3 in my room.

However, not one of our APC UPSes (around 25 of them in this building) was damaged nor any devices attached to them. I have a 1.5kVA APC that our servers are attached to and not a hiccup from it other than it beeping but the servers kept on running giving me time to manually shut them down. Had one off brand UPS that blew up the input MOVs but repairable. Considering the loss of neutral meant up to 380 volts was entering them, pretty happy it wasn't worse.

[InterestedObserver]

"1. Look way up on the top of the PEA distribution poles and you will see three wires carrying the three-phase power, not four wires. The neutral is not run, to save money, although there are a few exceptions. The source is a star (wye) connection."

Most of the time I have seen all four wires. The fourth wire (neutral) wire usually is an uninsulated ground wire (for lightning protection).

The grounded wire sometimes run along the very top of the distribution poles is for lightning protection. If it were a neutral for the system, which it is not, then the primary winding of the distribution transformers would be connected to it (L-N). Such an exposed neutral wire would be subjected to direct lightning strikes with the resultant severe electrical surges getting in your home or business.