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mikeames

mikeames

Senior Member
Location
Gaithersburg MD
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Teacher - Master Electrician - 2017 NEC
I was asked my opinion on this and my comment was that the idea is sound and in practice in industrial and commercial buildings, but hardly worth it in a residential setting. It was my opinion that someone was just trying to make money. I said I would post this to the forum and see what others thought. Am I wrong? Does this take advantage of the homeowner who does not have the background? Whats your take on this

http://hartmannelectrical.com/energysavingunits/
 
mikeames said:
I was asked my opinion on this and my comment was that the idea is sound and in practice in industrial and commercial buildings, but hardly worth it in a residential setting. It was my opinion that someone was just trying to make money. I said I would post this to the forum and see what others thought. Am I wrong? Does this take advantage of the homeowner who does not have the background? Whats your take on this

http://hartmannelectrical.com/energysavingunits/
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It is snake oil, not a sound practice, and not being used in the industrial or commercial setting by anyone with any sense (this is not exactly what they do).

It is a scam.
 
This subject has been discussed before. check this post.
http://forums.mikeholt.com/showthread.php?t=100338.

These units say they can reduce power bills. To do this the KWH's must be reduced. There is nothing in these devices to do this. The mfg usually has a capacitor installed and it will affect the power factor. However, if the customer is not being billed for a low power factor the unit is useless. Reducing a bill by correcting the power factor means that you must know what the power factor is. It is an engineered decision and its more that hanging a grey box on the service.
 
080630-2116 EST

mikeames:

It looks like fraud the way it is written relative to most residential usage. I suggest passing the ad on to the state attorney general to see if you can help stop this type of false advertising.

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mikeames said:
I was asked my opinion on this and my comment was that the idea is sound and in practice in industrial and commercial buildings, but hardly worth it in a residential setting.
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I think that sums it up... FYI most utilities have PF correction cap banks all over the place in most urban and suburban settings so this would not do much but drain mulla from someones pocket IMO. A lttle better motor efficiency but that realy depends....
 
e57 said:
I think that sums it up... FYI most utilities have PF correction cap banks all over the place in most urban and suburban settings so this would not do much but drain mulla from someones pocket IMO. A lttle better motor efficiency but that realy depends....
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In most industrial and commercial settings they do not usually correct the power factor at the service. They usually try to locate the capacitors closer to the var source down inside the plant. If there really were no concentrated var areas, and they were being charged a var penalty, they MIGHT put a capacitor bank near the service.

While I have seen var penalties on non-residential rates, I have never seen var penalties in a residential rate.

And you are correct about the moolah drain. You would be helping the POCO, as it would reduce the amount of var correction they would have to add, but don't expect any real thanks. For a residential and most small commercial customers, you will pay for var correction twice: once by the cost buried in your electric rate, and the second time when you buy this junk.
 
080701-0808 EST

e57:

Why would external power factor correction improve motor efficiency? Meaning a specific motor with a constant mechanical power load, constant input voltage, and constant frequency.

Without any power factor correction capacitors you should expect see motor efficiency increase as the input voltage is lowered, and also the inherent motor power factor will improve. Obviously there is a minimum voltage where this fails. The I^2*R losses go up as voltage goes down, but core losses go down with lower voltage. The relation between these will determine the minimum point.

Your building may see a slight drop in power used by power factor correction at each motor by reducing your internal wiring losses, but that is not motor efficiency. See mivery's posts at
http://forums.mikeholt.com/showthread.php?t=101262
and in particular, #25.

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