Short circuit in the system due to 220 voltage input installing in India

[Ironsave]

A 60hz transformer run on 50hz is a fire hazard, period, exclamation point !!!

Audiogon Thread discussing this:

http://forum.audiogon.com/cgi-bin/fr.pl?htech&1208831038

An excerpt:

"Having lived in Europe for 6 years, I have had lots of equipment that I used on the different 50/60HZ. US operates at 60HZ while Europe operates at 50HZ. IF your equipment is not switchable between 110 and 220V, there are step down transformers availabe all over Europe to reduce the voltage. The difference between 50HZ and 60HZ will effect the speed of a turntable. I owned a Dual Turntable when there in the mid 80s. Turntable was bought in the USA and taken over. I contacted Dual and was sent a different size drive cylinder for the motor to compensate.
Other than that, I had no issues. In fact, I still own a Carver Amp and the Dual turntable and they both function flawlessly even after being over there for 6 years"

Another thread at a different AV forum:

http://www.hifivision.com/surround-amplifiers-receivers/3299-help-wanted-urgent-220-50hz-110-60hz-onkyo-sr506.html

FYI: The "Holier than thou" attidude really detracts from The Forum.

OP; I wish you luck with your amp issue and finding the correct solution for you.

[djk]

"FYI: The "Holier than thou" attidude really detracts from The Forum. "

You are advocating something that could potentially kill someone.

I don't care if you earn the Darwin award yourself, but it would be criminal if someone got hurt because of your bad advise.

[djk]

Introduction

Initially, it all seems simple enough. You buy a piece of equipment from an on-line seller in another country, and expect that it should have the necessary switching to allow you to set the voltage to suit the mains supply where you live. With globalisation being the key term thrown around these days, you'd naturally expect that there should be few (if any) problems.

If the country you bought the gear from is Australia, Europe or the UK (but the equipment was built elsewhere) you might get lucky, but if it's equipment that's made in the country of origin you may not. Buying from the US or Canada will often cause problems, because the "export model" is generally not sold locally, so it will be made to operate only with the US mains voltage and frequency.

While the common answer is to just get a step down transformer to reduce your local mains (say 230V) to 120V, this may not solve the problem at all, and may introduce serious safety risks as well as the possibility of transformer failure. Unfortunately, the simple (and common) answer fails to consider many different possibilities, some of which may place the user and/or the equipment at considerable risk. One of the most common requirements is that people want to be able to use equipment from the US in Australia, Europe, etc.

The step-down transformer is not straightforward, although it initially seems that nothing could be simpler. Very few people seem to appreciate the various things that can go wrong, even those with technical training. "Information" from forum sites is almost always either wrong, overly simplistic or misguided. A small number of forum posters will understand the risks, but it's impossible for the average person to determine who is right and who's not.

4 - Frequency

Now comes the real can of worms. Many people believe (and will tell you) that the small frequency difference (50Hz vs. 60Hz) is insignificant, but this is not true. Many products intended solely for the US markets will have the transformer made for 60Hz. This has the advantage of making the transformer smaller than it would be if it could also handle 50Hz. Indeed, an advantage of 60Hz mains is that all transformers and induction motors are smaller than the 50Hz equivalent. The alternative is that in some cases, a 60Hz and 50Hz transformer may be the same physical size, but a 60Hz only version can use lower grade (and therefore cheaper) steel laminations.

If a transformer is designed specifically for 60Hz, and understanding that this makes for a smaller and/or cheaper transformer than would be the case if it could also handle 50Hz, why would anyone assume that this 60Hz tranny will work fine at 50Hz? The answer (predictably) is that it will not. An initial quick check will usually not show the problem ... it may need to be left on for a while before anything shows up. The problem is heat - the transformer will get (much) get hotter than normal, and may easily reach a dangerous temperature that will cause failure.

Some years ago, a company I worked for (in Australia, a 50Hz country) took delivery of six very large and expensive 48V power supplies for telecommunications use. These were made in the US, and used ferro-resonant transformers that were designed for 60Hz. I discovered the problem and advised management, but it was decided that I was being "alarmist". The first unit burnt out within 2 weeks of being installed, filled a large computer room with smoke, shut down a call centre and caused great deal of embarrassment for all. After this, management listened when I said there was a problem!

Part of the design process for a transformer is to ensure that there are enough primary turns to prevent the steel core from saturating. This depends on the voltage and the frequency. If the frequency is reduced (and 10Hz or 16.6% makes a big difference), there are no longer sufficient turns to prevent saturation. When the core saturates, the primary winding of the tranny draws much more current from the mains than normal - not just 16% more though, it can easily exceed 100% more.

The result is that the transformer overheats, and will eventually fail. Even most technicians will be unable to tell you that the transformer is saturating, because they either don't know what to look for, or don't have the equipment needed to look at the current waveform. There is actually no difference between decreasing the frequency or increasing the voltage by the same ratio. This is shown in Figure 3, where the voltage was increased from 240V to 270V - a mere 12.5% change.

Figure 3 - Magnetising Current at 240V and 270V

The oscilloscope shows voltage, but this is the output from a current transformer. At 240V, magnetising (idle) current is 32.3mA (which reads as 3.23V RMS), and the transformer will dissipate about 7.7W. A 12.5% increase to 270V increases the magnetising current to 69.6mA, or 18.8W - well over twice the normal idle current and power. Reducing the frequency by 12.5% will have almost exactly the same effect. Any transformer designed specifically for 60Hz will draw far more idle current than normal at 50Hz [2].

Since many modern products will already be operating right at the very limits (smallest possible transformer, etc.), a reduction of mains frequency will almost certainly push them beyond the point where failure is inevitable. It's no longer a matter of "if" it fails, but "when". Large 60Hz transformers may also growl with a 50Hz supply, and this can be loud enough to make a hi-fi amp unusable because of the mechanical noise. Electrical noise is also possible (i.e. noise from speakers), because stray magnetic flux can become a major problem because the core is saturated.

There is no cure for the above-mentioned issues, other than replacing the power transformer with a 50Hz version. The replacement will be expensive - assuming that the transformer is even available from the manufacturer. If not, you have an expensive paperweight that's of no use to anyone. It might be possible to operate the transformer from a lower voltage to avoid damaging saturation, but this approach cannot be recommended because it often leads to quite unacceptable consequences - serious loss of power (for an amplifier), internal supply voltages that are no longer regulated, etc., etc.

Note that operating a transformer designed for 50Hz mains at 60Hz reduces the idle current and power, so the transformer should run a little cooler. Therefore, products that are designed for 50Hz operation (destined for anywhere in the world apart from the US and Canada) will rarely have a problem with mains frequency, provided the supply voltage is correct. Inadequate design can still cause failure though.

---

Conclusion

First and foremost, avoid auto transformers. Make certain that the step-up/down transformer that you select has separate primary and secondary windings, is earthed properly, and has a VA rating of about double the maximum expected power drawn by the appliance. As described above, this may not be necessary, but is usually a good idea for most products.

Regarding the possible importance of frequency, it depends a great deal on the product and how it was originally designed (with/without a safety allowance for example). I would have liked to show the difference in idle current by changing the frequency, but unfortunately it requires a great deal of time and effort to set up. If anyone doesn't believe that the results shown here are real, then feel free to ignore this article in its entirety. You might be lucky, you might not. It is important to understand that some products will tolerate a lower frequency while others will not, and it's not usually possible to know beforehand those that will survive and those that won't. This can generally only be determined by testing the product.

There is no simple answer to the common question "Can you make it work?", when someone wants to know if it's alright to import product 'X' from overseas. There are simply too many possibilities for anyone to give a definitive answer - guesses are just that, and cannot be relied upon. This is especially true if the imported equipment is expensive and the seller doesn't know enough to be able to provide useful answers. In such cases, it may be better to avoid the item altogether because the cost of modification may make it more expensive than the same thing purchased locally.

There are some products (especially vintage), where modifications are simply not an option because they will devalue the item. In such cases, the best you can do is hope that it will be alright. Otherwise it becomes a rather expensive display product that can't be used.

For those for whom money is no object, motor-alternator units can be purchased (they are no longer as common as they once were though), or high-power electronic frequency and voltage converters also exist. These units range from a few hundred Watts to many kW, but are typically very expensive ... the mere fact that suppliers seem to never publish any prices gives you a good idea of the price range [3].

You've got to ask yourself one question: Do I feel lucky? Well, do ya, punk?

[JeffRay]

Sachin needs help with his problem. If he takes his amp to a competent technician he will be better served than taking long distance advice from people on a Forum; especially people who tell him he is ignorant and should throw his new equipment in the trash. Many power supplies are NOT frequency sensitive. In fact, in the Solid State low current area this is seldom a problem. In the high current realm of motors, inverters and such it is still an issue. The above article alludes to this very fact. I don't know the details of Sachin's power supply, therefore I counseled him to seek professional advice. He needs to do this anyway since he probably has some blown diodes on the Neutral side. If you look at a dual voltage, international power supply in any device you will see it is not that complicated. I have worked on power supplies that were damaged by reverse polarity, incorrect input voltages or power surges and found that they were 110v 60hz/220v 50hz capable even though they were not labeled as such. The manufacturer simply left out the wires and switch on the domestic model. I have seen others which were dual voltage by moving jumpers on the circuit board and the manual didn't say a word about it. I have seen other boards with empty component locations in the power supply to work with other voltages. Even if none of the above scenarios is the case, it is still not a problem for an experienced tech. Even if it needs a transformer change, not likely, most amps of this class do not have exotic or proprietary transformers. Once again, not a problem for a technician. People deal with these problems all over the world every day. It's not a big deal. Good luck Sachin, get your amp to a good shop and you will be fine.

No caps, colored text, or huge fonts, just saying . . . .

This is my last post on this.

jeff

[Ironsave]

djk,

"Do ya feel lucky punk?". Seroiusly?

Very disrespectful and quite immature....... Rather than come down to that level; I will just say it is a blessing that 98% of the forum members know how to argue a point without insulting or being flagrantly disrespectful. (Too bad there is no smiley for flipping someone off [H] ).......

I was posting my real life experience on this subject....... Whether you like it or not djk; I have been to other countries overseas and have used devices with a transformer. The most dangerous by far is a hairdryer.......

As Jeff pointed out; a tech could easily verify if this would be completely safe. Jeff's post makes the most sense..... Since the amp is blown anyway; have it inspected and verify it can in fact run @ 110/50hz without overheating and popping fuses. If so; repair as is; if not; get it modified.

Sachin; I truly wish you the best; and please post what your resolution is...... [Y]

Good Luck.

[mike stehr]

There are two posters that gave the best advice in my opinion...Dennis and JJK.

It would be more cost effective (and safer) to completely replace the fried amp with a 220 volt 50Hz version. It's probably a cheap amp anyway. So by the time you pay a tech to troubleshoot, repair the unit, and then buy a step down transformer,(which just steps down voltage with frequency still at 50Hz) you'll probably have spent as much cash than as if one had just bought a replacement.

I'm no tech, just a twit. But it is obvious from the paragraphs DJK listed that a 60Hz transformer running at 50Hz messes up the current/voltages ratings of the transformer. You don't want to exceed those ratings, or run it at a different frequency which changes the ratings. It's a gamble.

Granted, there probably is transformers heavy duty enough and designed for these sort of different frequency/voltages, but I doubt they will be in a amplifier inside a multimedia subwoofer box. It's a gamble, and not worth it.

They only reason DJK is being rude, is because it's a safety issue. Like he mentioned, he doesn't care if you hurt yourself. But one posting such matters on a audio messageboard, and when other folks safety is at risk, that's when it becomes a concern.

I respect that.

Remember, I'm just a twit. So don't slam me saying I don't know what the hell I'm talking about. I already know that... >

[Ironsave]

There are two posters that gave the best advice in my opinion...Dennis and JJK.

It would be more cost effective (and safer) to completely replace the fried amp with a 220 volt 50Hz version. It's probably a cheap amp anyway. So by the time you pay a tech to troubleshoot, repair the unit, and then buy a step down transformer,(which just steps down voltage with frequency still at 50Hz) you'll probably have spent as much cash than as if one had just bought a replacement.

I'm no tech, just a twit. But it is obvious from the paragraphs DJK listed that a 60Hz transformer running at 50Hz messes up the current/voltages ratings of the transformer. You don't want to exceed those ratings, or run it at a different frequency which changes the ratings. It's a gamble.

Granted, there probably is transformers heavy duty enough and designed for these sort of different frequency/voltages, but I doubt they will be in a amplifier inside a multimedia subwoofer box. It's a gamble, and not worth it.

They only reason DJK is being rude, is because it's a safety issue. Like he mentioned, he doesn't care if you hurt yourself. But one posting such matters on a audio messageboard, and when other folks safety is at risk, that's when it becomes a concern.

I respect that.

Remember, I'm just a twit. So don't slam me saying I don't know what the hell I'm talking about. I already know that... >

I have done alot of reading and research over the past day......

From what I have read; when dealing with an amp and this topic; the most likely result will be a hum; but overheating can result; depending on how beefy the transformer is.

I am able to admit when I am wrong. I was wrong implying it was 100% safe to use the step down transformer; without having done so on my promedias.

(The other computer speakers are a different brand and design).... I would bet today's promedias have different components; so even that may not be apples to apples (If I had done so with promedias).

I still maintain he will likely be ok; but in regards to being responsible for someone else's actions; I would be devestated for life; if someone was hurt as a direct result of my recommendation.

So OP; PLEASE; seek a tech or a suitable 220/50hz replacement amp. (I do not know if a suitable plate amp could be found overseas; but perhaps a receiver; etc???)

DJK; I still feel your manner of making your point was childish and very disrespectful. Instead of calling names; and posting quotes about how others are wannabe's and here is a list why....... Just make your point; and explain the risks; and why. This forum is built on respect; and is a great resource.

Your method will only tarnish that.

(A point can be made without treating the other person like crap)....

I am done with this thread. Lesson learned. Hoping DJK has learned one as well....... [^o)]

Edit; Typo on my part. Sorry JJKIZIAK!!! [:$]

[JJkizak]

The lesson I have learned with 40 years of electronic/electrical experience are once you have fried

an electronic chassis with excessive voltage input there are the obvious replacement parts (burned/shorted) and the not so obvious that show up after the repairs are

completed. It is possible that every integrated circuit on the board could be damaged if the board so uses them. How anyone could interpret my answer as

insensitive is insensitive to me.

JJK

[JJkizak]

Ironsave:

Thanks.

JJK

[Ironsave]

Dude,

Again..... My typo.

My apology was from the heart.....

Thanks for understanding. [:$]

[deafbykhorns]

Isn't DJK an electronics engineer? I think I would listen to a professional before taking advice from the internet. Just because Wiki says so doesnt make it right. I'm sure these were designed on a budget so I wouldnt trust this transformer to have the extra windings.

I think the WAF would be low if the house burnt to a crisp.........

[Ironsave]

Isn't DJK an electronics engineer? I think I would listen to a professional before taking advice from the internet. Just because Wiki says so doesnt make it right. I'm sure these were designed on a budget so I wouldnt trust this transformer to have the extra windings.

I think the WAF would be low if the house burnt to a crisp.........

I would not know DJK's profession.

Just because you have a career doing something does not give you the right to belittle and insult others who may not be electronics engineers....

Instead; you should be respectfully trying to educate others by sharing your knowledge in a constructive way. You are not God.

I may be wrong; but:

A. Was truly trying to help the OP.

B. Do not deserve an immature and completely disrespectful response because someone else has years of training; and I am just sharing my experience.

C. DJK; I would like to tak this off forum. Please PM me for my email.

D. DBKH; Please read several posts up. I would be devestated if someone got hurt because my advice backfired.......

OP.... Good Luck.

[deafbykhorns]

Iron- we all sometimes forget this is just a forum, some amatuers, some engineers, we appreciate your research.......

Engineers are a different breed, I work with them every day. Some people confuse what your reading with arrogance but its not. With engineering its never based on 100% knowledge of a condition but with design margins and some assumptions to reduce risk. DJK just feels you don't have the technical merit to solve the problem and is looking for facts. What DJK is trying to say is its really not worth the risk of burning down the house. Now if you gave him some technical data to base your theory on, he would listen, that is how I communicate with engineers.

[mike stehr]

you should be respectfully trying to educate others by sharing your knowledge in a constructive way.

He did. Now you not to use 60Hz transformers at 50Hz.

Sometimes you have to yell and be rude to get other's attention when their own safety and others are at risk. It lets them know you are serious. Some think constructive criticism is rude...it's not.

"You are not God"

But Dani Filth is? [:S]

[Ironsave]

you should be respectfully trying to educate others by sharing your knowledge in a constructive way.

He did. Now you not to use 60Hz transformers at 50Hz.

Sometimes you have to yell and be rude to get other's attention when their own safety and others are at risk. It lets them know you are serious. Some think constructive criticism is rude...it's not.

"You are not God"

But Dani Filth is?

Um; No he did not. That was not constructive criticism. Calling someone "punk" on an internet forum generally can be considered an insult.

Doing so face to face generally constitutes an *** whipping. In the wrong setting; it could be just as hazardous as an overheating transformer.......

In regards to Dani Filth.....("But Dani Filth is God?") Literally? No. Figuratively; in the heavy metal world? Hell yes. Does that clarify it for you? []

[Ironsave]

Iron- we all sometimes forget this is just a forum, some amatuers, some engineers, we appreciate your research.......

Engineers are a different breed, I work with them every day. Some people confuse what your reading with arrogance but its not. With engineering its never based on 100% knowledge of a condition but with design margins and some assumptions to reduce risk. DJK just feels you don't have the technical merit to solve the problem and is looking for facts. What DJK is trying to say is its really not worth the risk of burning down the house. Now if you gave him some technical data to base your theory on, he would listen, that is how I communicate with engineers.

That may be exactly what he meant..... That still does not excuse the lack of respect or the insults.....

He is insulting and criticizing because someone does not communicate his way..... But he is guilty of the same inability to meet a basic (perceived) standard, in regards to basic respect and communication....

Dbkh, no offense, but why can't he log in and express what you just did? Could it be because he lacks the communication skills necessary? No one is perfect.....

[deafbykhorns]

Um; No he did not. That was not constructive criticism. Calling

someone "punk" on an internet forum generally can be considered an

insult.

Doing so face to face generally constitutes an ***

whipping. In the wrong setting; it could be just as hazardous as an

overheating transformer.......

Dbkh, no offense, but why can't he log in and express what you just did? Could it be because he lacks the communication skills necessary? No one is perfect.....

It's a moot point and a waste of time to further debate, this isn't the

old school yard. Have you ever watched the movie "Dirty Harry"? That punk statement was simply a quote from this movie to get your attention. I would get over it and move on to something more

constructive. Then again, theres not much to do outside of Chicago with a high of 20, wow! [st]

[Ironsave]

waste of time to further debate, this isn't the old school yard. Have you ever watched the movie "Dirty Harry"? That punk statement was simply a quote from this movie to get your attention. I would get over it and move on to something more constructive. Then again, theres not much to do outside of Chicago with a high of 20, wow!

Not till tomorrow.... (Go Bears! [] )......

[mike stehr]

In regards to Dani Filth.....("But Dani Filth is God?") Literally? No. Figuratively; in the heavy metal world? Hell yes. Does that clarify it for you?

Well...No, not in my eyes...but that's ok. To each his own...it doesn't mean you can't enjoy Cradle of Filth.

Dani's voice kinda grates on me. But so does King Diamond's. But I still like King Diamond and old Mercyful Fate. I'm sure there is many heavy/death/grindcore/speed/doom whatever metal bands you and I can connect with.

As far as DJK being rude. Oh well, life goes on. Life's too short to get in a huff and wear holes in one's stomach over some guy on the internet.

[Ironsave]

In regards to Dani Filth.....("But Dani Filth is God?") Literally? No. Figuratively; in the heavy metal world? Hell yes. Does that clarify it for you?

Well...No, not in my eyes...but that's ok. To each his own...it doesn't mean you can't enjoy Cradle of Filth.

Dani's voice kinda grates on me. But so does King Diamond's. But I still like King Diamond and old Mercyful Fate. I'm sure there is many heavy/death/grindcore/speed/doom whatever metal bands you and I can connect with.

As far as DJK being rude. Oh well, life goes on. Life's too short to get in a huff and wear holes in one's stomach over some guy on the internet.

Yeah, Cradle is kinda like White Castles. (Ever had one?)

First time is kinda like " Eh; what's the big deal?"..... but for some reason; you go back..... Before you know it.......

You are hooked...... [H]

I do love Cradle.........

As for DJK; I am over it. I already wasted too much time and energy over this thread........ Life is short.... Enjoy every minute.....

[H]