Comments on: Electricity Power Savers : Do they work ?

By: Rohit

Rohit — Sun, 11 Dec 2011 21:40:25 +0000

@rananjay When a synchronous motor is run in a certain mode, it acts as a capacitive load (like a capacitor). So it can help in power factor correction. Note that it is not a servo motor.

By: rananjay

rananjay — Sat, 10 Sep 2011 04:56:38 +0000

sir my company has purchase one power saver panel of globtel company , but is principle is different as you told , in this panel one servo motor and one small transformer is situated, so plz tell me that how does this work

By: Sumant

Sumant — Mon, 22 Aug 2011 06:42:27 +0000

I want to buy a Power Saver ….Is this suotable or not ? I t really works or only Money Wastage . Can somebody suggest me ?

By: Balu

Balu — Mon, 06 Jun 2011 12:51:26 +0000

Hi,

Please let know what is best power saver to buy?

-
balu

By: Pacfan

Pacfan — Sun, 22 May 2011 04:56:07 +0000

The Oreva Power Saver works in 2 ways. First, it corrects the power factor of the system through the capacitors built-in in the unit. You could see a significant drop on the ampere being drawn but it doesn’t translate into savings. This is because capacitors only cancels out the reactive power being drawn from the power utility, hence the drop in amperes. When you measure the ampere by using an ammeter, the reading there is the apparent power of the load (true power & reactive power). Capacitor only cancels the reactive power but it doesn’t affect the true power (kw) where you are being billed by the power utility. Unless there is a power factor adjustment clause in your contract with the utility wherein you get rebates if power factor is improved, no significant savings on the electric bill will be realized. However, installing capacitors has intangible savings like reduced wire capacity, improved voltage etc…

The second feature of Oreva is the auto transformer built-in to their power saver. This is how they get the savings. This auto transformer reduces the input voltage from 2%-5% before going to your electrical load. How will this affect the electrical load and its consumption? For inductive loads, if the motor is not 100% loaded, a signifacnt savings in true power can be realized. The usual thinking of people is when supply voltage drops, an increase in current being drawn will increase, thus the same power is consumed. This is true but not in all cases. If the motor can perform its work with reduced supply voltage and with reduced power, you will get savings. This is evident on some loads like electric fans where the motor is usually not 100% loaded or not heavy-laden. Supplying it with reduced supply voltage which will result to reduced power and torque, would not translate into additional current draw because the motor can drive the shaft at reduced power with no additional torque needed, hence a savings on power cost. But for inductive loads that uses compression, a little savings can be expected at reduced supply voltage. For resistive loads like heater, reduced supply voltage will translate into savings but not all times … let me explain. For hair dryers and shower heater, savings can be achieved because you will not notice the drop in the temperature if reduced voltage is supplied and reduced kilowatt was utilized. But if you boil a water using an electric stove, the same power will be consumed because it will take a longer period to boil water with reduced kilowatt, hence the same power is consumed. For light bulbs and flourescent, reduced supply voltage will immediately translate into savings but you have to be satisfied with a slight decrease in the lumens or brightness of the bulb.

I am just surprise why Oreva is marketing their product based on the principle of power factor correction. I would suggest they market their product based on the context of Voltage Optimization which is already accepted in different parts of the world. This is just a suggestion.

By: Amit Murarka

Amit Murarka — Fri, 18 Mar 2011 05:58:18 +0000

does these power saver work on 3 phase line? or they are helpful only on single phase line

By: umha

umha — Tue, 15 Mar 2011 06:42:54 +0000

laptops an handphones are inductive or resistive loads?

By: WiseTechie

WiseTechie — Sun, 27 Feb 2011 13:14:54 +0000

@Roland – So according to you improving power factor will result in a fatter electricity bill , because that is what Rahul wrote.

Anyway, to get to the point, I don’t have time to feed the trolls.

By: Roland

Roland — Mon, 21 Feb 2011 03:03:52 +0000

Congratulations Rahul…it is very obvious that you do understand electrical system very well. You are 100 % correct that energy meters registers only the real (active) power (KWhr) and disregards reactive and apparent power. Improving power factor has a lot of beneficial though, one is maximizing system capacity, however, in the case of individual small appliances, would have a negligible effect.

Seems it is necessary for Mr. Wise Techie to consider retaking his “power apparatus” (is it a subject in your course?), otherwise you definitely will misguide many…

By: mj

mj — Tue, 14 Dec 2010 14:15:07 +0000

i have my own computer shop last day someone ask me if i am interested in power saver then he told me it help to down my monthly bill into 30%-40% then they push me to give a down payment which is 2500 then i will have my reservation for the unit the total price of the unit is 9500… but i am not believe to them guys can u help me is there a power saver that fit for computers.?