Electrical/voltage fluctuations

vidro3 · July 2011

Something odd has started to happen at the homestead.

Thursday night I ran the a/c and a small fan like this one and all was well.

Friday night my roommate bought an a/c and started to run that as well. Knowing that both 5,000 BTU, 4.8 amp a/cs were on the same 15 amp circuit, I thought there might be some problems.

Indeed, the fan of my a/c would periodically get faster and slower. It wasn't the compressor going on and off, but the fan speed was fluctuating. I used an extension cord to plug my a/c in on another circuit. Same issue of fan speed slowing and then going back to normal.

I connected only my small fan to the extension cord on a different circuit and it still slowed and sped back up.

Anyone know what could be causing this fluctuation in the fan's speed?

This situation first occurred at night when there was virtually nothing else drawing power.

whyfi · July 2011

That this started happening at the same time as the other A/C unit was brought in might be coincidence. At this point, the only constants are the A/C unit and the electrical supply to your apartment; if it's a problem in the apartment, I think it would manifest elsewhere. Also, I would think that any electrical supply problem would affect the A/C as a whole, rather than just the fan, which has considerably lower power requirements than the compressor.

I would a) check that there's not some stupid "breeze," fan function, that mimics gusts b) see if the fan is getting gunky around the spindle.

vidro3 · July 2011

both A/Cs on and my a/c and small fan are both slowing down and coming back up to speed in tandem.

con ed was here and said the service going into the house was working properly

bohuma · July 2011

When we bought our HDTV and associated audio equipment, the salesperson explained that NYC is subject to voltage variations and recommended we purchase a voltage regulator, which is a device that we plug into the wall, and plug all of our expensive video and audio equipment into. This device ensures that regardless of what the input voltage is, the output is 120 volts. It has an LED screen on the front that indicates the input voltage, and it often shows fluctuations.

An electrician we had installing a light in the pantry closet elaborated further that NYC electricity is "dirty", that is there is a lot of noise on the transmission lines and the city is at capacity and often has shortages of electricity and ConEd turns the voltage down, sometimes as low as 106 volts. He sells and installs the voltage washers for main panels, so you could get an electrician to install one for the whole house, so that no matter what voltage ConEd is sending into the main panel, the output is 120 volts.

All this is a long way of saying that the demand for electricity in New York City is higher than the supply and sometimes ConEd will cut back on the voltage to ensure everyone's lights go on when they flip the switch. Think about that next time your elected official wants to close a power station or some group wants you to sign a petition to prevent the construction of high voltage supply lines.

catwalkertexasranger · July 2011

1st thing you need to do is establish what outlets are associated with the l5amp circuit breaker that is used for the ac and the fan. Often the outlets are not replaced inside the apt. The contact surfaces inside the outlet can become worn from a variety of reasons. It's pretty simple and cheap to have them replaced. The price range without labor for a new outlet is 1-4 dollars.A new ckt breaker is about 10 dollars. As the ac is turned on there is a current surge as the motor starts up, once the unit is on the current demands may vary with the thermostat setting. The obvious reduction in fan speed is a reason for some concern. Con Ed/Nature will not identify any internal apt problems.

Is the circuit dedicated to the AC?Spend a little time doing simple things. Is the cord to the ac warm or hot to the touch? Are the switch plate covers warm near the power cord from the AC?

The basics are. The service comes into the apt, landed on the breaker location in the dist panel, and then out to the outlet(s)IF there only a couple of outlets associated, all the screws and connections can be checked within 30 minutes once all are identified.

Don't have a fire because something abnormal was observed and not investigated.

vidro3 · July 2011

@bohuma

what kind of voltage regulator did you get?

bohuma · July 2011

something like this:

http://www.pcrichard.com/catalog/product.jsp?modelNo=MPHDP1800

We decided if we were going to spend several thousand on home theater equipment, having it fried by ConEd was probably not a good idea. We have surge protectors on all our expensive electronics.

cool the kid · July 2011

I lost a lot of electronic equipment at my place in Crown Heights. External hard drives, a "vintage" Yamaha A/V receiver, and a shit ton of light bulbs. Haven't had any problems in Manhattan. If you have anything electronic worth protecting I would DEFINITELY invest in some kind of protection... something AC-DC-AC w/battery backup would be best. I can only imagine what causes the differences in power quality

whynot_31 · July 2011

It was all covered by insurance, but I once had all of my low cost electronics fried when the not genius building electrician disconnected the neutral prior to the positive, causing 220 volts to be fed to all outlets.

The acrid smell of fried electronics greeted me after work. Everything on a surge protecter (computer, stereo, tv, etc) lived, but everything else -clocks, microwave, bulbs, appliances, etc- got fried.

vidro3 · July 2011

last night everything was working fine. not sure what changed.

weird.

Electrical/voltage fluctuations

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