Does anyone have any information on voltage optimisation?
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winnie
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- Springfield, MA, USA
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- Electric motor research
"Voltage optimisation"
That sounds like someone took a general concept and turned it into a trademark. If there is a box somewhere that someone is calling "voltage optimisation", I've never heard of it, nor know what it does.
Maybe a little context here would help? IMHO you should always optimize voltage for the conditions, but the conditions include things like available supply voltage. When I run incandescent lamps for bike headlights, I use a little PWM regulator to maintain a constant supply voltage, optimized for good efficiency and lamp life. My work on electric motors involves systems to optimize the applied voltage for best efficiency given the current mechanical load. Lots of situations where optimization is called for
-Jon
That sounds like someone took a general concept and turned it into a trademark. If there is a box somewhere that someone is calling "voltage optimisation", I've never heard of it, nor know what it does.
Maybe a little context here would help? IMHO you should always optimize voltage for the conditions, but the conditions include things like available supply voltage. When I run incandescent lamps for bike headlights, I use a little PWM regulator to maintain a constant supply voltage, optimized for good efficiency and lamp life. My work on electric motors involves systems to optimize the applied voltage for best efficiency given the current mechanical load. Lots of situations where optimization is called for
-Jon
JohnHurst
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- Las Vegas, NV
If I had to hazard a guess, he's probably referring to the Nola concept, or it's close kin the concept of using a transformer to reduce a standard "high" voltage to nominal. The second concept I've seen bandied about for European markets, where equipment desgned for, say, 380V now finds itself having to work in 400V or higher environments. Google "powerperfector" for an example of this.
winnie
Senior Member
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- Springfield, MA, USA
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- Electric motor research
Thanks John, that looks like just the sort of snake oil that would treat 'voltage optimisation' as a proper noun.
http://www.powerperfector.com/downloads.html
There is quite a bit of theoretical plausibility to what they are selling; this isn't a fuel line magnetizer The issue is: are they overstating the value of what they are selling, and what are they using in terms of smoke and mirrors.
For example: http://www.powerperfector.com/downloads/ohms_law.pdf gives the example of a resistive load, and states that an 8% reduction of supply voltage on a resistive load will give a 16% savings. Well this is true if you consider instantaneous power...but if that resistive load is a thermostatically controlled heater, then the reduced voltage and reduced power simply means that it runs for a greater percentage of the time, using the same net _energy_ over time.
If the reduced supply voltage means _less_ output (for example lamps may be dimmer), then you will see energy savings because you are inadvertently doing without some benefit of electricity. This is a well known feature if you use dimmers on incandescent lights: reduce the voltage and you reduce the power consumed, but the light is dimmer and less efficient. Reducing voltage could very well reduce light output and save energy. If you have too much light in a facility, then you are probably much better turning lights off then turning down the voltage. On the plus side: regulating supply voltage does good things for lamp life. If you know that you have a solid 220V, then you can use 220V lamps, which will be more efficient at 220V than 240V lamps operating somewhere between 220 and 240V.
Electric motors will clearly have both an operating range, as well as a particular voltage in that operating range that is most efficient. If the motors are designed for 220V, but are regularly used at 245V, then they are probably in their acceptable operating range, but not at their most efficient operating point. However a good VFD should adjust the voltage to the motor in just this fashion, and has the benefit of better matching the motor to its particular mechanical load.
Phase imbalance does significantly damage the efficiency of three phase motors. I don't know how common serious phase imbalance is, nor how well these devices correct such an imbalance. A VFD should correct for this as well. Of course, there are many situations where a VFD is not appropriate; having proper supply voltage an proper phase balance is probably a net win.
I look forward to hearing more. How well do real world numbers compare to the sales numbers, for example. How well does their system stabilize voltages and balance phases. How well could the same thing be done with 'generic' components rather than their proprietary tools?
-Jon
http://www.powerperfector.com/downloads.html
There is quite a bit of theoretical plausibility to what they are selling; this isn't a fuel line magnetizer
The issue is: are they overstating the value of what they are selling, and what are they using in terms of smoke and mirrors. For example: http://www.powerperfector.com/downloads/ohms_law.pdf gives the example of a resistive load, and states that an 8% reduction of supply voltage on a resistive load will give a 16% savings. Well this is true if you consider instantaneous power...but if that resistive load is a thermostatically controlled heater, then the reduced voltage and reduced power simply means that it runs for a greater percentage of the time, using the same net _energy_ over time.
If the reduced supply voltage means _less_ output (for example lamps may be dimmer), then you will see energy savings because you are inadvertently doing without some benefit of electricity. This is a well known feature if you use dimmers on incandescent lights: reduce the voltage and you reduce the power consumed, but the light is dimmer and less efficient. Reducing voltage could very well reduce light output and save energy. If you have too much light in a facility, then you are probably much better turning lights off then turning down the voltage. On the plus side: regulating supply voltage does good things for lamp life. If you know that you have a solid 220V, then you can use 220V lamps, which will be more efficient at 220V than 240V lamps operating somewhere between 220 and 240V.
Electric motors will clearly have both an operating range, as well as a particular voltage in that operating range that is most efficient. If the motors are designed for 220V, but are regularly used at 245V, then they are probably in their acceptable operating range, but not at their most efficient operating point. However a good VFD should adjust the voltage to the motor in just this fashion, and has the benefit of better matching the motor to its particular mechanical load.
Phase imbalance does significantly damage the efficiency of three phase motors. I don't know how common serious phase imbalance is, nor how well these devices correct such an imbalance. A VFD should correct for this as well. Of course, there are many situations where a VFD is not appropriate; having proper supply voltage an proper phase balance is probably a net win.
I look forward to hearing more. How well do real world numbers compare to the sales numbers, for example. How well does their system stabilize voltages and balance phases. How well could the same thing be done with 'generic' components rather than their proprietary tools?
-Jon
- Location
- San Francisco Bay Area, CA, USA
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- Electrical Engineer
winnie said:Thanks John, that looks like just the sort of snake oil that would treat 'voltage optimisation' as a proper noun.
http://www.powerperfector.com/downloads.html
There is quite a bit of theoretical plausibility to what they are selling; this isn't a fuel line magnetizer
Balanced snipped for brevity
-Jon
Excellent answer. I have seen this concept pushed on people a lot lately, especially the "benefits" of lowering the voltage going to lighting. As Jon implied, it all depends upon whether or not you consider lower lumens on your work surface to be a non-issue. Having done plenty of lighting designs in the past, I can say that good designs usually put the desired amount at the desired height. A reduction in light can often result in a reduction of worker productivity, sometimes it can even compromise safety. It should not be taken at face value. If you do have too much light, how much too much? Can you just turn some off or switch to lower wattage lamps? Same difference.
I love the argument about reducing the voltage going to resistive heating loads. Jon hit the nail on the head, but it's surprising how many people fall for that.
Voltage imbalance is important, but can also be corrected by careful arrangement of loads in a system.
Most of the rest is bunk. The Nola devices are not as beneficial as people claim, this has been discussed over and over.
The one caveat is however, that SOME people have a high line voltage, high enough that taps on the distribution transformer don't correct it enough (assuming there are taps). In those cases, these "optimizers" like the Power Perfector can offer some tangible benefit. But they overstate the number of people out there who have over voltage issues, most installations are well within tolerances.
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