Power factor correction devices: Can they really reduce your electricity bill?
Mohit Arora - June 1, 2012
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Hi Mohit Arora,
30-Jul-13
First of all congrats for this elaborate article, To update you, I discussed with few vendors in delhi of such power saver devices, many of them are ready for a court agreement to prove that their product reduces the electric bill, they are ready to give 100% money-back Guarantee, if bill does not get reduced after installing their device
your views on this
Mohit
New Delhi - Jul-13
30-Jul-13
First of all congrats for this elaborate article, To update you, I discussed with few vendors in delhi of such power saver devices, many of them are ready for a court agreement to prove that their product reduces the electric bill, they are ready to give 100% money-back Guarantee, if bill does not get reduced after installing their device
your views on this
Mohit
New Delhi - Jul-13
Jul 30, 2013 5:55 AM EDT
I am aware of power factor correction only benefiting the supplier of you electricity by making reactive power more in line with purely resistive power but when you have solar panels on a roof generating electricity through the inverter surely if you have a low PF with no PF correcting device fitted to the meter your PV system with feed less KW into the grid...
My 5KW PV system on a full sun day generates around 45-48KW/day but only feeds in 28-30KWh and I still use approx 5-6KWh from the grid.... prior to installing the PV system I used to use around 16-18KWh/day on full sunny days...
My question is: "by installing a PF correcting device will the grid feed-in KWh /day increase... I believe it would as the PV system is a power generating system feeding a house with a low power factor...
I am an Electricial contractor and also lecturing at an Electrical college.. Any engineers out there that could clear this up... thanks
My 5KW PV system on a full sun day generates around 45-48KW/day but only feeds in 28-30KWh and I still use approx 5-6KWh from the grid.... prior to installing the PV system I used to use around 16-18KWh/day on full sunny days...
My question is: "by installing a PF correcting device will the grid feed-in KWh /day increase... I believe it would as the PV system is a power generating system feeding a house with a low power factor...
I am an Electricial contractor and also lecturing at an Electrical college.. Any engineers out there that could clear this up... thanks
Dec 6, 2012 8:15 PM EST
# Even though a PFC device may not reduce the electricity bill, it does
# not change the fact that inductive loads run more efficiently with
# corrected or at least improved power factors and thus means less
# wear and tear of the appliance (i.e., the motor since current drawn
# by the motor is reduced), improving product life.
The appliance will not run "more efficiently" and you are not reducing the current drawn BY it. You are just injecting a counteracting current elsewhere in the system.
# One situation where PFC can be extremely useful for residential
# situations is in the design of a backup energy system like a Home
# Inverter or UPS (Uninterruptible Power Supply). Correcting the power
# factor from 0.65 to 1 results in a 35% reduction in the size (VA rating),
# thus a less expensive inverter can be chosen though power
# consumption remains the same.
It would be a very rare home or business that would have a power factor near 0.65 at the full capacity of the inverter/UPS. And inverters may have trouble driving capacitive (PFC-correcting) loads.
# not change the fact that inductive loads run more efficiently with
# corrected or at least improved power factors and thus means less
# wear and tear of the appliance (i.e., the motor since current drawn
# by the motor is reduced), improving product life.
The appliance will not run "more efficiently" and you are not reducing the current drawn BY it. You are just injecting a counteracting current elsewhere in the system.
# One situation where PFC can be extremely useful for residential
# situations is in the design of a backup energy system like a Home
# Inverter or UPS (Uninterruptible Power Supply). Correcting the power
# factor from 0.65 to 1 results in a 35% reduction in the size (VA rating),
# thus a less expensive inverter can be chosen though power
# consumption remains the same.
It would be a very rare home or business that would have a power factor near 0.65 at the full capacity of the inverter/UPS. And inverters may have trouble driving capacitive (PFC-correcting) loads.
Jun 7, 2012 9:55 AM EDT
The only component that will remain same is the Real power with or without PFC, so billing does not get impacted for residential user. However don't understand your first comment as to why you think appliance will not run efficiently even with PFC. It will defeat the purpose and make it a redundant device even for Industrial.
For your next comment, agree , for all practical purpose power factor may not be as bad for residential user since the inductive load is minimum, however that’s the whole point. If power factor for a residential user starts to really become bad (for e.g Home floaded with Neon lights that have really bad power factor with no other appliance turned on ) , utilities will start billing based on reactive load just like Industrial users.
For your next comment, agree , for all practical purpose power factor may not be as bad for residential user since the inductive load is minimum, however that’s the whole point. If power factor for a residential user starts to really become bad (for e.g Home floaded with Neon lights that have really bad power factor with no other appliance turned on ) , utilities will start billing based on reactive load just like Industrial users.
Jun 8, 2012 2:56 AM EDT
Windhorn is correct. Although a capacitor in parallel with an inductor does improve the overall power factor, it does not change the actual current through the inductor. The claim that a motor (inductor in parallel with the PFC capacitor) will draw less current is incorrect.
Nov 28, 2012 1:09 PM EST
If you are at the end of a distribution line, where poor power factor has caused the voltage to drop, the addition of a power faction correction device might permit the voltage to rise up to a more proper value where your appliances operate more efficiently. If such conditions don't exist then I agree that it won't affect your electric bill.
Jun 4, 2012 3:52 PM EDT
In my home, I believe I need more PFC because when my Air Conditioning unit kicks "on" the lights in my house dim for 500mS - which is noticed every time by yours truly. I am looking into measuring the Power Factor to determine the PFC needed......
Jun 4, 2012 3:52 PM EDT
Your problem isn't power factor - it's inrush current. A large motor, like the one in your AC compressor, has alot of inertia which must be overcome to bring it from at-rest to spinning at full-speed. Current surges into it and causes a corresponding voltage sag for a brief moment when the compressor kicks on. This is normal and shouldn't be considered a problem unless you have problems with electronics resetting and such.
Jun 7, 2012 4:44 PM EDT
Absolutely agree. Also recall that starting current(or load) for these kind of appliances is way higher than rated current (rule of thumb would be to assume starting current = 6x rated current), the reason for huge inrush current.
I stay in India and here we do have often have problems with respect to fluctuating voltage back from the mains, so most of the houses are equipped with Voltage stabilizers on inductive loads (Motors, Refrigerators, AC etc) to take care of any voltage surge or fluctuations.
I stay in India and here we do have often have problems with respect to fluctuating voltage back from the mains, so most of the houses are equipped with Voltage stabilizers on inductive loads (Motors, Refrigerators, AC etc) to take care of any voltage surge or fluctuations.
Jun 8, 2012 3:07 AM EDT
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