Pick your brains on power consumption

I connected two capacitors (80MFD @370VAC) one to each leg of the 220VAC (and attached at the neutral buss) at my utility's power meter to the house. It actually reversed the power meter for a brief moment. Then the utility's power meter just stopped. I'm confused, when I tested these capacitors individually using an actual test equipment wattmeter, I got the following readings: 119.60 VAC, 3.64 amps, 424~449 VA, 0~1 watt, 0.0 or

1.0 Power Factor sometimes ranging from .02~.06 pf. After 12 hours the test instrument read 0.16kwh consumed . So the test instrument says the Caps are consuming power, yet the utility's power meter does not register, it is just stopped. I am adding these Caps as a surge protector (and to raise the Power Factor) , due to the charge imposed by the impedance of the primary lines and charge stored in the iron core of transformers when the utility goes dead or is reenergized. The utility's Capacitor Bank is located 30 miles from me, not giving me any benefit. I'm also confused how the Caps can act in the same manner as DC Caps, complementing the power source, But AC Caps, I'm guessing could be out of phase, actually drawing power. Does any body have any ideas or suggestions about this?
Reply to
n
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Where are you that the utility charges for PF? or provide the rate structure. I have never heard of "due to the charge imposed by the impedance of the

Caps to my knowledge are not used for surge protection. MOV, metal oxide varistors are what is used.

Caps do use power, they take and store a certain value then when the voltage drops they give it back. (simple answer) That is why they are used on starting motors.

The utility cap bank is not for you. it was installed for them.

As for the rest of your post I do not understand what and where your measuring or installing the caps. What test instrument are you using?

Reply to
SQLit

80 microFarad jives with the 3.6A.

Presumably a little current transient occurred when the capacitors were connected to the live lines that happens to have caused the meter to budge.

Perhaps 0.01 W - 1 W is too low to start the Utility's disk meter turning.

The charging current due to the line capacitance?

Well, there's not really any 'charge' stored in the iron core. I guess you are talking something about residual magnetism, inrush, and maybe resonance or ferroresonance.

It is because the caps draw current out of phase that they can complement the power source. Loads generally draw no reactive current or lagging reactive current. Caps draw leading reactive current, which is synonmous to saying they supply lagging reactive current. Thus the source will not need to provide, or transmit, as much lagging reactive current when there are capacitors near the loads.

There will be some power consumed by capacitors as there is some resistance to the current flowing in and out. I would also guess that the dielectric electrons and/or atoms shift around with alternating voltage, and experience some friction losses.

My suggestion is to not attach those capacitors. If you must install something, install something that is UL listed etc. And get the help of a professional if you're not familiar with electrical work. Capacitors located 'at your meter' would not even save you the meager available power savings you could get by installing caps at equipment such as motors. I'd be surprised if your utility charges you for poor power factor in a house, so no savings there. I'm not confident that a pair of 80uFd caps will give you much surge protection, but, if even if they do save you by shunting some disastrous surge, how sure are you that the caps will be OK and not e.g. catch fire? If this seems like a fun little science experiment to you, you are better off not trying it.

I've seen surge caps are used at substations. I think they are supposed to decrease the rate of rise of transients.

Reply to
operator jay

Do not connect anything ahead of the main breaker, or you risk a fire in the event of a fault.

Capacitors are not surge protection. Why are you raising the power factor? What is it now? How much capacitive reactance do you need to bring it to .98? As for the rest of this, please explain what it is you are trying to fix.

The utility installs capacitors to improve the power factor on their equipment, thus reducing the size of the generator, wiring, etc for a given power output. You do not benefit from this. As others have pointed out, you pay only for real power consumed at your residence.

Ben Miller

Reply to
Ben Miller

Thank you guys for your input. Operator Jay, I appreciate your detailed explanation. Let me give you guys some history. I bought this rural house in 1994, thirty miles south of Eugene, Oregon. It had about a dozen or more appliance tossed into the yard, burned out stoves, organs and amps, frigs, washing machines. I tore the house done and moved a MFG home onto the lot. The power company (a extremely small co-op utility, with limited resources) added a new meter pole and installed a new transformer about 80 feet from the meter (I had to remind the installer to return to the transformer an install the ground wire from the transformer to the ground rod that he forgot to do, he had left it dangling and thought he was done). Underground cable was used from the meter into the MFGH. I also have several out buildings. Over the years, I've lost 3 VCR's, dozen of 60W screw in florescent lamps, two electronic ballasts used in those skinny green tipped 4ft florescent lamps. These losses occurred in all building not just the house. I tried tightening ever screw to every beaker, neutral buss , every everything. The utility has put a data logger behind the meter and has nothing to report, except my loads are unbalanced. Somewhere I have an Email from them, they sent me a PDF file of the chart recorder.

Last month, the utility was her relocating power poles and lines ( by the way the new primary wire is looks like ¼ inch cable spliced into the old original primary line that looks like 20 gauge wire viewed from the ground. Anyway, my son and I was watching TV with video that was passing thru a VCR from our Satellite to the TV. Then the house went dead. The power was cut at the primary disconnect at the end of the street for the crew to handle the primary wires. While the crew was next to my transformer, I told him to remove the coiled pigtail they had added in 1994 from the disconnect fuse to the primary tap. I told them that 5 turn wire was an air-core inductor, so he made it straight. When the job was completed and power restored, my 3rd VCR that I was just using, was dead. Each of these VCR's over the decade lost their switching power supply.

Even now, when my electric furnace shuts off, I hear a click in my computer amplified speakers that are attached to my TV in the bedroom. I tightened all the joints in the 200amp panel in the house. Every bedroom is on it's own 20amp breaker using 12 Ga. Wire. Before I added these two 80 MFG Caps, I could here the same click in the computer speakers when the bathroom lights were turned off (4ft florescent). Those Caps are located about 100 feet of wire away from the bathroom and speakers.

I never lost any equipment when I lived in Lancaster California (Southern California Edison).

Those reading I quoted in the first post came from bench testing the Caps using the test instrument made by Seasonic model SSM-1508RA. It measures v,a,w,va,hz,pf,kwr,hr. It plugs into a 120 outlet and has it's own outlet to plug in the device you want to test. My computer has a PF of .64 .

My computer has its own separate APC UPS, my TV has its own separate APC UPS, my stereo, satellite, DVD, and remaining entertainment electronics has its own separate APC UPS. APC uses MOV's, I have power strips with MOV's. Given that those VCR's were protected by APC UPS and failed anyway, well... MOV's self destruct and you don't know when they've reached their end of life, unless you want to kill a lot of time bench testing. I think MOV's alone are doomed to an early death, but when paired with some meaty Caps that can absorb the longer slower spikes they can complement each other. What I don't know is was value of Caps to use. I've seen Triplet uses a combination of Powdered-Iron Toriod Cores bi-wound filter inductors with Caps & Mov's in a expensive power strip. These look good for items you can plug into the strip but does nothing for a whole house solution.

It was perhaps a poor choice of words to say, "due to the charge imposed by the impedance of the primary lines", however I think these lines store instantaneous voltage for a couple of microseconds in the form of inductance or capacitance as does the

iron core of transformers when the utility goes dead or is reenergized. The lineman working on my transformer pole admitted that when he works on underground AC primary lines he must discharge them, because after power is removed those wires are charged with a high amount of DC voltage because the wires are now a DC storage capacitor, I could easily understand that.

I don't really care about the power factor as far as cost savings go, but I think it explains the death of so many appliances.

The Caps were installed in their own metal box, mounted onto the meter box with 8 amp fast blow fuses attached to each Cap. Then the wires passed thru a grommet into the meter box where they attach to dual 20amp breakers. The common was connected to the neutral buss. Each of the three wires, each contain three 14ga. Enamel wires twisted and soldered together, then solder directly to the Caps, to eliminate oxidation and resistance. There is a 80 ft of cable from the Caps before entering my home or outbuildings.

The utility is ignoring the very long history of failed appliances on this property. When I bought this place in 1994, everything from the power pole transformer to the grounding rods, to every piece of electrified wires have been replaced. The only remaining common denominator is the primary power distribution from the utility itself.

Reply to
n

You might consider an isolation transformer between the crappy utility supply and yer house, drive your own ground. Investigate the idea first.

Phil Scott

Reply to
Phil Scott

The caps and toroids form a filter for high frequency noise. They are not transient suppressors. As you pointed out, the MOVs do that.

It has nothing to do with it. One appliance doesn't care about the power factor of another one. And again, adding capacitors to the service conductors won't change anything at the appliance. The change will be upstream, on the distribution and transmission side!

You are simply adding capacitance to what is already on the line, which you seem to feel is causing a problem. Won't this result in more capacitance, and make the problem worse?

You are running around with a cure in search of an illness!

The first thing you need to do is identify the cause of the failures. Electronic appliances could be affected by transients, harmonics, over-voltage, undervoltage, etc. Each of these conditions has a different solution. You can't fix it until you know what the problem is. People responding on this group are giving you ideas that can solve various problems, but nobody knows what YOUR problem actually is. My approach here would be to install data logging equipment to monitor voltage, harmonics, and transients for a minimum of one week (several weeks would be better). Then, armed with facts, you can select the appropriate mitigation techniques. Also, you may have recourse through the utility if you present them with test data. If you don't have such equipment, you can rent it or enlist the services of a consultant.

Ben Miller

Reply to
Ben Miller

Ben's answer was right on. However, every line has inductance and capacitance so that if you are having problems that do not occur commonly elsewhere, it is unlikely to be due to this.

However, there may be some source on your service line that is producing spikes. The data logger used by the utility probably only recorded fluctuations in the rms voltage and completely missed short term transients. You need something that will do so. Dranetz(sp?) is a known maker- try to rent one or get the utility to rent or borrow one- a typical chart recorder indicating rms voltage is inadequate.

Reply to
Don Kelly

I am in the UK, when this type of problem (with damaged equipment), occurs on our domestic single phase system at 240 Volts, the cause is usually found to be a faulty earth connection on the neutral of our distributed, 3 Phase,

400/240 Volt system. (It is unusual for anything other than 240 Volt, single phase to be supplied to a domestic installation in the UK). This causes the other phases to swing plus or minus, about the nominal 240 volts, the magnitude depends on the loading on other domestic properties on the 3 phase system. The US system of having a centre tapped, 220/110 Volt supply for light and heavy loads, would present the same type of problems if there was a faulty earth connection. I would suggest that you have a competent electrician investigate your supply; and have the electricity supplier investigate theirs. Jaymack
Reply to
John McLean

--------------------- That is true and may be the factor. However there was monitoring done by the utility- it may not have been at the right place to catch this.

Reply to
Don Kelly

The utility used a cheap data logger behind the power meter. It has limited memory, so the sample rate was very slow so they could leave it on for two weeks or more. Impossible to see transits under those conditions. Given that there is no separate ground wire to earth on this logger, I don't see how it can monitor earth related issues, it may have been grounded to the meter box, if so the neutral wire to the transformer would mask any earth currents. The graph emailed to me from the data logger only indicated Voltage and Amps. Power factor, Watts, & VA were NOT measured. Samples were probably once per minute.

Reply to
n

Such data collection would miss the problem in either case.

Something that you can do for yourself.

a) see if others on the same distribution circuit have problems. If so - go back to the utility.

b) Use a multimeter and measure voltage to to neutral on different circuits. This is most easily done at the panel. Switch various things on and off. What you are looking for is the voltage on the more heavily loaded side to drop appreciably while the other side rises accordingly. If possible, if there is a separate ground rod or water pipe connection, try measurement to ground as well. If a) it may be due to spikes. proper measuring equipment needed- utility responsibility. If b) it is a local grounding problem and the neutral connection needs to be checked for poor connections anywhere between the transformer and the panel (inclusive). It happens. I have seen 160V on one side and 80 on the other leg in such a situation.

Don Kelly @shawcross.ca remove the X to answer

Reply to
Don Kelly

Here is something to check, make sure any two port device (such as a VCR or TV: cable and power) is protected by a surge protector that protects BOTH the power and the cable. Often home electronics failures involving two, or more, port devices are caused by differences in potential of the grounds of the two systems. The typical UPS will NOT fix this since they pass the ground straight through.

The ground of your cable/satallite system, along with the grounds of the telephone and electric system should all be bonded in a common point. Sadly, this seems not to be the case in too many installations.

As for light bulbs, join the club. I seem to change bulbs too frequently. Two fixes: CFLs or 130V rated bulbs.

Charles Perry P.E.

Reply to
Charles Perry

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