Comments on: 2/8 – Electrical equipment: power factor

By: James

James — Wed, 21 Jul 2010 00:20:16 +0000

I just purchased an energy saving device off Ebay. I had heard of the KVAR brand units but when I surfed the web and called the company, I couldn’t get specs for the product. So I went to Ebay and I ordered a unit out of Honk Kong with advertised good specs if you can believe what is stated on Ebay. The unit looks as good as any but on careful inspection after receipt, I noted it didn’t say where it was made. I decided to open the box to see how the electronics were configured and I was surprised by the simplicity of the device. It was clear to me that I would see a two capacitor device but I expected a circuit board with overload… What I found appears to be two capacitors hooked to a monitor light for the front of the box attached by a variety of wires and nothing else. I have pictures for your review if they will help. Here is what is advertised for specs that I have doubt the box will do but I don’t want to confront the seller or Ebay without a second and third reliable opinion.

Advertised specs that I don’t see how are possible ( full list can be posted upon request ):

1. double insulated

2. Surge Suppression – 6500 Joules

3. Let Through Voltage – 150V Line-To-Neutral

4. Spike Protector: Utility Spike And Electrical / Lightning Storms

5. Transient Noise Reduction: MOV (Metal Oxide Varistor)

6. … Thermal & Overload Protection

here is just a start of my concern: it says double insulated. There are three wires for the 220/240 VAC installation ( two red and one green wire ). As you would expect, one red wire goes to each 120vac leg of your electric panel and the green goes to the ground bus. Well in the box, the green wire comes into the all metal box and goes to a bolt that hold a flat metal crush clap over the two caps. So, when you look at #3 above to read 150V line to neutral, one would think that if the transient voltage stays too long over 150VAc on one of the legs, that energy will be diverted to the ground wire to protect what you have plugged in within your home. But as you can see, with the way it is designed, if that ground wire does not make a good contact with the home’s ground bus then the exterior of the box could be hot. But I don’t see how #3 is possible anyway with no circuit board to clap the voltage to the 150vac to start. So, how could this unit be double insulated? I need an elect engineers opinion so I know if I am looking at this list correctly. With no circuit board or other discrete component- where is the MOV of # 5 or how is #6 possible?

By: Imran basha

Imran basha — Thu, 17 Dec 2009 11:16:32 +0000

power factor is nothing but the difference of angle between current and voltage….

By: radhakrishna.su.

radhakrishna.su. — Thu, 10 Dec 2009 00:45:48 +0000

As I undrestand that Power factor means that Power factor of system/apparatus. say system,
power factor of system is ratio between from source, power given to the system(apparant power) and power converted from the system(active power).
This because of due to presence of energy storing elements in the system, the given power is not fully converted from the system and some amount of the power(reactive power) is returned to the source

By: OJAJUNI ranti

OJAJUNI ranti — Sat, 28 Nov 2009 08:56:06 +0000

Ian desirous of knowing and actually working to deliver power factor improvement package to many end users. Can you heip?

By: THOMAS

THOMAS — Wed, 18 Nov 2009 06:11:50 +0000

THER ARE VARIOUS EQUIPMENTS R DEVICES THT CAN BE USED TO IMPROVE THE PF OF A SYSTEM…. A CAPACITOR IS AN EXAMPLE OF A PF IMPROVEMENT DEVICE…THER ARE MOTORS USED TOO 4 THIS PURPOSE…. BT 4 A LARGER SYSTEM….

By: v.suresh kumar

v.suresh kumar — Fri, 13 Nov 2009 09:47:02 +0000

How to increase power factor from 0.55 to 1.0 at 150 kw load.

By: Iragunima Owajiokimun J

Iragunima Owajiokimun J — Tue, 10 Nov 2009 16:49:20 +0000

power is the cosin of the angle of displacement between voltage and current . It does not apply to a pure resistive circuit