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#1
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power isolation transformer voltage
i am interested in getting an ac isolation transformer for a piece of
gear that has a ground loop in my studio. i see ones that are 110, 115 120v input voltage. my wall voltage is supposed to be 120v actually my furman pl-plus meter shows about 125v. would i be okay using any of these voltage inputs? or should i get one that is closest to my actual wall voltage? are the "medical grade" transformers ok for audio use? |
#2
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power isolation transformer voltage
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#3
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power isolation transformer voltage
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#4
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power isolation transformer voltage
thx for the relpies. how will a transformer with a 115 input voltage
differ from one with 120 input, (both having 120v output) in a situation like mine--getting around 125v from the wall? i have a 115v transformer available to me and i'd like to use it if possible for a "quick fix" i realize that it would be better to find the underlying problem but unfortunately i'm in a rental apt so no messing with the ac. also almost all my lines are unbalanced and i've run out of audio isolation transformers! my only other option is lifting ac ground and i'm not about to do that.. |
#5
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power isolation transformer voltage
wrote in message oups.com... thx for the relpies. how will a transformer with a 115 input voltage differ from one with 120 input, (both having 120v output) in a situation like mine--getting around 125v from the wall? It will raise the voltage by a factor of 120/115, so you'll get about 130v out. It would be better to wire it backward. Feed 125v to the 120v side and take the output from the 115v side, which will deliver about 120v. |
#6
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power isolation transformer voltage
By the way, transformers should never be used at more than a few percent
above their rated voltage. Feeding 120v into a 115v transformer winding is OK, but I don't want people come away with the impression that any overvoltage is OK. If the overvoltage is more than slight, you'll saturate the core and have a fire. Anything designed to be connected to the AC line can tolerate maybe 10% overvoltage or more, because the AC line varies. |
#7
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power isolation transformer voltage
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#8
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power isolation transformer voltage
mc, so you're saying that I plug the ac wall power into the "output" of
the xformer and the audio device into the "input" of the xformer? would doing it backwards like this have any adverse effects on the power quality or safety of the unitt? |
#10
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power isolation transformer voltage
In .com, on 12/18/05
at 07:50 PM, said: i am interested in getting an ac isolation transformer for a piece of gear that has a ground loop in my studio. i see ones that are 110, 115 120v input voltage. my wall voltage is supposed to be 120v actually my furman pl-plus meter shows about 125v. would i be okay using any of these voltage inputs? or should i get one that is closest to my actual wall voltage? If you are simply working through a problem with a home studio, do what you need to do. If an isolation transformer on the power and/or signal lines solves *THIS* problem, go for it. I say "*THIS*" problem, because the next time you add a piece of equipment, you'll be fighting another issue, and another, and another. As other posters have stated, you should hire an electrician who is familiar with low noise grounding practices and fix the underlying problem with your electrical system. Don't hire the inexpensive guy down the block because he could easily make the problem worse. Warning: Good grounding requires discipline. A single violation of the rules will ruin the result. If you are not using balanced audio distribution, you'll be fighting an uphill battle. Your voltages are more or less normal and may vary during the day or by season. (Power companies may adjust the local voltage in response to seasonal demands, such as lots of airconditioners.) are the "medical grade" transformers ok for audio use? They would be excellent, but expensive. "Medical" electronics must have very low, controlled leakage. These are desirable for your application. ----------------------------------------------------------- spam: wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15 13 (Barry Mann) [sorry about the puzzle, spammers are ruining my mailbox] ----------------------------------------------------------- |
#11
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power isolation transformer voltage
"Joe Kesselman" wrote in message ... wrote: thx for the relpies. how will a transformer with a 115 input voltage differ from one with 120 input, (both having 120v output) in a situation like mine--getting around 125v from the wall? US consumer electric power is nominally 110V, though I've seen it range as low as 90 (in an old building with inadequate wriring) and as high as 130. In general, devices are designed to tolerate about 10% variation; that 90V line *did* upset some equipment. Hasn't been nominally 110V for half a century. Design center was 117V in the 1960s, 120-125V today, I think. Someone once posted a very long and detailed history of this. So unless your power supply is inadequately designed, running a 115V box on anything from 110V to 120V shouldn't be a problem. Agreed! |
#12
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power isolation transformer voltage
wrote in message ups.com... mc, so you're saying that I plug the ac wall power into the "output" of the xformer and the audio device into the "input" of the xformer? would doing it backwards like this have any adverse effects on the power quality or safety of the unitt? Assuming it's really a transformer (and not something more complicated), transformers are reversible. For example, a 120-to-12-volt transformer is also a 12-to-120-volt transformer, depending on which way you connect it. If you're not comfortable doing this, get help locally from someone with electronics experience. |
#13
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power isolation transformer voltage
i see ones that are 110, 115 120v input voltage
Isolation transformers usually have the same I/O voltages. Are you sure you're not considering other types of transformers ? Touché! It could be an autotransformer that does not isolate and wouldn't do him a bit of good. |
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