[diyguy]

Originally Posted by Thad E Ginathom

Inverter technology is, apparently mature.

my colleague just purchased an LG 1.5T split and he was told that they have stopped non-inverter machines. Not sure how correct this is though.

[raddy]

Originally Posted by Thad E Ginathom

............Absolutely it will! It will maintain the temperature and humidity levels so well that you will never feel warm or cold while it is running: you will just feel comfortable. It works so well that it makes non-inverter AC look silly. Like comparing a comfortable car to a bullock cart.

So why is everybody not buying them? I for one, If I was wealthy and did not have to think much about either initial cost or cost of ownership, would not buy anything else.
.....

So. Are you trying to say that always running ACs are a lot more prone to break down than ACs which works on demand and in full speed?

[aim120]

Inverter compressor is the future, pretty much all refrigerators these days have inverter compressor and they also seems to have a warranty as high as 10years.
In air conditioners the only way manufactures are going to meet ever stringent energy efficiency norms are going the inverter way.

As far as the electronics(VFD) that control the compressor, that is mature enough since it's used by pretty much every single modern electric car out there from a reva-I to a Tesla model S/x/roadster, rimac etc and two wheeler.

[Thad E Ginathom]

Originally Posted by raddy

So. Are you trying to say that always running ACs are a lot more prone to break down than ACs which works on demand and in full speed?

Not at all. Putting what I did say into a few words: inverter technology is more complex and more expensive to repair. And, anecdotally, it seems to go wrong more often.

Mechanically, (input from our engineers please), starting and stopping times are more stressful than running.

[Prowler]

Originally Posted by Thad E Ginathom

Not at all. Putting what I did say into a few words: inverter technology is more complex and more expensive to repair. And, anecdotally, it seems to go wrong more often.

Mechanically, (input from our engineers please), starting and stopping times are more stressful than running.

Absolutely it will! It will maintain the temperature and humidity levels so well that you will never feel warm or cold while it is running: you will just feel comfortable. It works so well that it makes non-inverter AC look silly. Like comparing a comfortable car to a bullock cart.

It depends on so many factors - the ingress of heat from outside through the walls and glass, how many times the door is opened and so on. The main difference between the normal induction motor which runs at 3600 rpm and the Variable Frequency drive Brushless DC motor which runs at somewhere between 1100 rpm and 4000 rpm (?) - is the former either runs or stops whilst the latter runs at a speed determined by the need.
The start/stop causes momentary surge and the starting current demand is a lot higher than the running current.

But the thermostat/control circuit for the conventional compressor has to deal with thermal hysteresis. Simply put if you set the thermostat to 26 degrees, the compressor cuts off at around 25 degrees and waits till it rises above 27 degrees (for the sake of clarity simplified here). So there is an inherent temperature difference. In the case of inverter, this can be minimized.

Many companies offer 10 years warranty only on the compressor for the inverter models ( the normal compressors carry 5 years warranty) but not for the control circuits or power electronics. Other things being equal, the chances of a mechanical failure rate is lower than an electronics failure rate. Power electronics often lead stressful lives. All it takes to send them to premature failure is a large amplitude surge.

A couple of years ago a bad thunderstorm killed lots of electronics in my neighborhood. My NIC and routers were fried along with the control circuit of one split conventional AC. It cost me barely 1k to replace the control circuit. I was glad it was not an inverter model.

[aim120]

Another big advantage of inverter AC is the ability to run on a UPS/Inverter/Solar. Since there is absolutely no Inrush current, all you need is a UPS/inverter that is slightly more capacity then a inverter AC wattage.

Not the case with a regular AC which can overload the inverter causing it to trip.

When you run it on Solar you will always get a voltage within spec of the AC operating voltage.

offtopic:
I am planning to say goodbye to the Grid, those incompetent lazy idiots in Bescom don't bother to attend to High voltage complaint despite having video/photo evidence, I have measured as high as 350v for prolonged hours in night. In one instance voltage came as high as 440v when 2 phases touched due to some procession of Ganesha, enough to screw up my 46" sony tv, no voltage stabilizer can protect at that voltage. No more, I have had enough of the lazy government employees in BESCOM, can't wait to go for solar.

[anupmathur]

Originally Posted by aim120

....
....
offtopic:
I am planning to say goodbye to the Grid, those incompetent lazy idiots in Bescom don't bother to attend to High voltage complaint despite having video/photo evidence, I have measured as high as 350v for prolonged hours in night. ....

It would be great if you could post your photographic evidence of voltage hitting 350 volts.
I can understand 440 volts because of a fault condition but cannot imagine how 350 could be possible, and for hours!

[JLS]

Originally Posted by Thad E Ginathom

Not at all. Putting what I did say into a few words: inverter technology is more complex and more expensive to repair. And, anecdotally, it seems to go wrong more often.

Mechanically, (input from our engineers please), starting and stopping times are more stressful than running.

Inverter technology involves more complex electronic components and its intent is to avoid starting/stopping of compressor. This helps in three ways:
a) as you rightly said continuously running is less stressful for mechanical parts than starting and stopping
b) it helps in energy conservation also - a typical motor(which drives a compressor) draws six times more current at the starting time and this results in much more energy consumption when every 20 mins compressor re-starts
c) gives more constant temperature compared to conventional AC, where it starts cooling when temperature upper limit reaches and it stops cooling when temperature lower limit has reached

Inverter ACs are less likely to go wrong (at least on mechanical parts) due to less frequent start/stops.
However the electronic components involved are both
a) very complex - typically involves - converting AC @50 Hz to DC and then converting it again to AC @ a different frequency - to control the compressor speed and in turn controlling temperature
b) much costlier than used in simple filter and amplifier circuits due to much higher power rating involved
Your observation of inverter technology seem to fail more often may be due to some brands using electronic components which may not be correctly rated for the power they need to handle.

[raddy]

So. Inverter ACs are expensive to maintain if not to purchase.

Thanks everyone for your very valuable feedback.

[Thad E Ginathom]

Originally Posted by JLS

Your observation of inverter technology seem to fail more often ... ... ...

Is entirely anecdotal, and may be based on simple prejudice! I know that some of us got burnt by Sharp: I have no real idea what the actual failure rate of inverter machines, on the whole, here in India is. Of course, the dealers say that, properly installed, there will not be a problem: they would say that!

[aim120]

Originally Posted by anupmathur

It would be great if you could post your photographic evidence of voltage hitting 350 volts.
I can understand 440 volts because of a fault condition but cannot imagine how 350 could be possible, and for hours!

They where in different, like couldn't care. Their logic was that, I was the only one complaining. In the picture you can see the voltage very very high.
I had to endure it for week or so happened mostly after 10:30pm. It was resolved after repeated follow up. The neighborhood can thank me, I could hear everyone's UPS/inverter in my street beeping, yet everyone slept, while I went and woke up the Lineman, who said to come in the morning and the morning lineman/AE/JE etc said complain to the lineman at night and cycle continued for week happened twice month apart.

I even almost finalized a custom designed 10kva servo stabilizer which could handle input 320v and give 230v output, it could still give about 250v at 350v input but even that cannot handle voltages like 440v before it could correct or shut output, in a second there is still 50cycles of super high voltage going to your connected load. A CVT stabilizer would do it in lesser time but it has its own drawbacks.

So best option for me is to go with solar, eventually everyone will.

[diyguy]

Originally Posted by aim120

while I went and woke up the Lineman, who said to come in the morning and the morning lineman/AE/JE etc said complain to the lineman at night and cycle continued for week happened twice month apart.

Here is what worked for me. The AE/JE and lineman won't act. I had only two Phases for six months in a new rented home. Then on new years eve, it became one phase. I wasn't comfortable with multiple ac load and all other stuff running off just one phase. I called emergency fault and the EB van came and said the second phase was burnt and only the JE can help as cable will need to be dug and replaced. They said they cannot do anything and went away. Was patient with the JE. Called him every day for a week. He kept giving me stories that he has bigger problems in other areas etc. I finally got fed up when the JE told me he is in court and cannot do anything till the next day. I looked up the EB site, got the number for the EB chairman's office. Called his number, spoke to his secretary and told him my problem. He told me to call 'Distribution' for my area. He also told me he will follow up. I called Distribution and he took the JE number from me. Within 10 mins I got a call from the JE who was supposedly in court and he told me he was sending someone to check. The lineman went to my home in 30 mins and miraculously got the second phase working in no time. I pushed them that they need to fix the third phase as well. Since they were under the gun, I was told they will come the next day and will fix the third phase too. They promptly arrived the next day, spent many hours trying to determine where the cable fault was and fixed it. The JE came home and I told him that I complained to the chairman's office due to his inaction and the linemans lies. After completing the job they came for their tip, which I was in no mood to give. Since they had slogged for a few hours I finally parted with 500rs and threatened them that I wouldn't hesitate to call Distribution henceforth. This was a satisfying experience for me and am sure will work for you as well. Give it a shot before you spend big bucks on your own setup.

[carboy]

Originally Posted by diyguy

I had only two Phases for six months in a new rented home. Then on new years eve, it became one phase.

How do I figure out how many phases I have in my flat?

[raddy]

So fixing a non inverter AC even in cases of electrical fluctuations would be economical is it? Can't we make an Inverter AC run for longer time periods if we installed a good stabiliser?

[anupmathur]

Originally Posted by aim120

....
I had to endure it for week or so happened mostly after 10:30pm. ....

Thanks for posting that image.
The only way 350 volts can reach a consumer is if it comes straight from the sub-station with malfunctioning equipment. This represents extreme apathy and ought to be punishable by law.