Power factor correction device

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p51

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I have a customer who owns a car wash and asked me about installing a power factor correction device on all the motor loads at his carwash.The information that he recieved in a flyer states "The PFCD reduces the amount of power drawn from the utility by storing (in its capacitors) otherwise lost electricity caused by the inductive motors. The PFCD supplies that stored electricity back to your inductive loads,thus causing you to decrease your demand from the utility." Any thoughts or opinions on these PFCD's, the manufactuer claims a 20% reduction in power costs. Thank you
 
p51 said:
. . . the manufactuer claims a 20% reduction in power costs.
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That may be true, but it is likely that it will be the utility company, and not the business, that saves those costs. One question: Have your customer look at the electric bill for the business, and see if the utility charges an extra fee for low power factor. If so, then that, and only that, is the money that your customer might save. If not, then any energy savings that the device will create will benefit only the utility.
 
081210-1031 EST

p51:

Select search above and enter

power factor correction

some of the results relate to your question. You need to determine if your customer is paying a penality for poor power factor. If not, then the capacitors will be of totally insignificant value. Probably a net loss.

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I would also add that even if he is being penalized for poor power factor and could save money by improving it, DON'T go with the product(s) in the flyer. Maybe its just me, but I don't trust those guys.
 
drbond24 said:
I would also add that even if he is being penalized for poor power factor and could save money by improving it, DON'T go with the product(s) in the flyer. Maybe its just me, but I don't trust those guys.
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I totally agree. The fact that the first thing they do on their website is spout the scam that they can save 25% on residential customer's bills is proof that they are nothing but a rip-off outfit, stay away!

IF your customer is being penalized for poor PF, then the way to fix it is to just add capacitors on the load side of each FVNR or FVR starter. They are very inexpensive. Commonwealth Sprague (now Eaton), Myron Zucker, and Aerovox all have perfectly adequate PFC setups and provide very simple charts for picking the correct size. They come in industrial enclosures with fuses and blown fuse indicators, all features that you want to have. If this is a problem that your customer needs to solve, then steer him AWAY from the scam artists and establish yourself as the guy who really cares about saving him money.

But again, if he is not being penalized for poor power factor, it's a waste. These things do NOT save energy in the way the scammers want you to believe, so your customer will be throwing his hard earned cash out the window.

Other REAL energy savings tips for car washes however:
If he has air blowers that use heaters to help dry the car in colder climates, put VFDs on the blower motors and adjust the speed down in between cars. Because the heater elements get damaged by turning on and off constantly, the caw wash controllers will often run the heaters between cars when it detects a string. But they then also have to run the blowers as well to avoid overheating the elements. But the blowers don't really need to run full speed at those times, and even a few minutes per hour of reduced power will add up.

Some more advanced car wash systems measure the humidity in the ambient air and adjust the blower speed down to only the level needed on any given day, rather than always run them full speed based on the worst case scenario.

Put VFDs on the pumps rather than run everything full speed all the time and throttle the output during low pressure functions such as soaping, applying waxes etc.

It all adds up.
 
p51 said:
I ...by storing (in its capacitors) otherwise lost electricity caused by the inductive motors. The PFCD supplies that stored electricity back to your inductive loads...
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Otherwise lost? - No
The above is a two way street...
 
charlie b said:
Have your customer look at the electric bill for the business, and see if the utility charges an extra fee for low power factor. If so, then that, and only that, is the money that your customer might save.
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Even then, wouldn't they have to notify the POCO to re-test the PF with the PFC in place before they see any savings?
 
I work at a mine and we have about 2500 hp in multiple motors of different sizes. The utility company said our power factor was bad obviously and if we did not put capacitors on our system they would put them on there side and we would not save any cost. There engineer even was nice enough to do the calculations for us on cap size. Our motors are not always on all at once and he did not figure that. we pole mounted them and they were on all the time unless you manually threw switch at pole. So with no motor load our caps were still in line and power factor was bad the other way. Came to find out they were sized wrong and needed some type of auto switching. He does not work there anymore and all that was a waste. definitely for that size facility put caps on load side.
 
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