Dirty power, VFDs

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arcwick08

New User
arcwick08
I don't know about the rest of NC, but Western (Asheville area) seems to have some seriously dirty power. I've spoken to a couple local electricians who've described it as such.
In personal experience, I've been through two midi-lathe VFD units as the result of whatever hokey power is pumped out over here.

I'm on the precipice of purchasing a nice new Jet 16-42, but would really rather avoid cooking its VFD.
Are there any affordable power cleaning/regulation devices out there that will protect the 220v 2HP Jet?

I had a decent surge-protector hooked up to the other machine after the first vfd bit the dust, but then the next died the same death. My assumption is that the voltage at the line is varying pretty substantially (which a surge protector would not protect against), though I've not put a meter on it to confirm.

I welcome any advice here....
 

Jeff

New User
Jeff
Wow, "dirty power" is a new one for me. It seems that those fluctuations could affect anything and everything within the home.

http://www.psihq.com/iread/linecond.htm

Have you talked to your local power company about it? In the simple case perhaps they could install such a device on the incoming line to your meter that'll cover a wide range of line fluctuations. :confused:
 

Newboy

George
User
I had some equipment in Louisiana at a place with bad power. I bought some TrippLite power conditioners, and all the problems stopped.

I get them at Amazon. A 20 amp one is about $300.

I have them all around my house now.

You can plug them into a receptacle that has noisy power, anywhere from 80 to 130 V, and the output is a perfect 120 V sine wave at 60 Hz.
 

KenOfCary

Board of Directors, Secretary
Ken
Staff member
Corporate Member
I had a problem blowing out modems back in the day when I lived in Virginia. It turned out the house ground was faulty. They put it under the porch which was too dry. Moved it out in front of the porch and the problem went away.

Check your ground. They sometimes hit a rock and stop trying to get it deep enough in the mountains.
 

CrealBilly

Jeff
Senior User
I had a problem blowing out modems back in the day when I lived in Virginia. It turned out the house ground was faulty. They put it under the porch which was too dry. Moved it out in front of the porch and the problem went away.

Check your ground. They sometimes hit a rock and stop trying to get it deep enough in the mountains.
+1 correct ground is just as, if not more important than the electricity its self. Without a properly grounded electrical system all kinds of strange things happen. Including excessive metering usage.

When I fist moved to NC I heard the same thing "dirty power" our lights would dim every time the gas pack AC unit would kick on from the house across the street. I looked at the transformer on the pole and our house and the one across the street were the only ones on that that transformer. I called out duke power and while the repair man was standing there I called my neibor and asked them to turn down their thermostat and when their gas pack kicked in sure, enough our lights dimmed. It turned out it was my neibors ground clamp was loose. A quick fix and all was good from there on out. My neibor also realized a decrease in their electric bill and were very happy.
 
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Endless Pursuit

Jeff
Senior User
Your power company is required to provide you with power that is within a regulated set of specs. I looked but can't find the exact regulation but I had a relative who worked for Allegheny Power and they were regularly "defending" the quality of their current.

As has been said above, most of the time it is a grounding issue, usually at the consumer location. Some times it's a branch on a main line or after effects of lightning (arced insulators) or a bad trunk ground.

Call your power company's Customer Service #. They have folks that track this down for you. Actually, they WANT to know.
 

aplpickr

New User
Bill
One of the best things you can do is to remove as many of the chances for dirty power to kill your electronics. Physically disconnect your lathe from its power source every time you leave the shop. Plugs, switches, disconnects.
 

red

Papa Red
Red
Senior User
One of the best things you can do is to remove as many of the chances for dirty power to kill your electronics. Physically disconnect your lathe from its power source every time you leave the shop. Plugs, switches, disconnects.
I do this on a daily basis. Every time I leave the shop for the night everything gets unplugged. I do this as a safety feature but now I see there is an added benefit.

Red
 

cpowell

Chuck
Senior User
I had a problem blowing out modems back in the day when I lived in Virginia. It turned out the house ground was faulty. They put it under the porch which was too dry. Moved it out in front of the porch and the problem went away.

Check your ground. They sometimes hit a rock and stop trying to get it deep enough in the mountains.
QFT. Amazing how many problems are caused by inadequate grounding.
 

nblanton

New User
Nate
I work for Duke Energy, in operations at a Nuke plant here in NC. I'm not speaking officially for the company, but we are pretty tightly regulated by NERC on our voltage and frequency we put out on the grid. If there was 'dirty power' it would affect more than just your locality due to the interconnection between plants and utility operators. Actually, minor frequency ripples can trip our plants off line and cause major disruptions. Its not something from the utility, it is more than likely caused by something in your home, like the grounding issues mentioned above.
 

jrfuda

John
Corporate Member
I agree with checking the ground. My well pump is on a VFD and, when first installed, it was causing interference with some light fixtures in the house. I spoke with the manufacturer and they recommended I check the ground. I did, added a second ground (8 feet away, tied to the first) and it fixed everything. I imagine the VFD for the pump would have been short lived had I not fixed the ground. Good thing my lights gave me a warning sign.

Sent from my HTCEVOV4G using Tapatalk
 

arcwick08

New User
arcwick08
Thanks for all the suggestions everyone... I'll have a shifty at the panel and the box and see if anything looks out of whack to my amateur eye. I should have mentioned that my woodshop is actually in an industrial storage building of sorts (multiple rented units). Each unit is on its own meter and I'm usually the only person there in the evening working. When I'm not there, I flip a surge switch to disconnect power to my equipment. Basically, whatever is cooking the VFDs at my unit is most likely happening while I'm there and is probably something in my shop or on my box.
I'll give Duke a call and ask them to just do a quick once over of the connections at the meter and pole.
 

kooshball

David
Corporate Member
Give the utility company a call.


I had my lights slightly dim at times when appliances were in use and at other times for seemingly no reason. I noticed the same thing at a neighbor's house although it was very subtle and apparently I was the only one who noticed it. This went on for months, maybe a year then one night I noticed it got more severe. I noticed that some lights were not just slightly dimming and returning to normal but actually running dim. Luckily I was home when it went south and I shut off all critical appliances at that time and did some investigating. I noticed some outlets would drop to 109v when a load applied to their circuit and other circuits would rise above 130v. I called an electrician who suggested that there was an issue with the neutral line. I checked my main panel outside and everything was clean and visually fine...didn't go any further there by myself so I called the power company to check the supply.


A tech showed up and very quickly identified a bad connection on one of the legs into the house at the splitter box in my yard and verified the issue that I was seeing was due to that connection. He repaired the connections and we see 125v, dead nuts no matter what is going on. No more flashing / dimming lights; problem solved.


My neighborhood is 20-25 years old and he told me that he has been replacing many such connections in the area...the gear used then and its proximity to the ground lasts 20-25 years. They are now replacing those old boxes with elevated ones.


In my case the power on the grid is clean, bad connection between my house and the grid was the problem. Easy, quick and free fix from the town of apex...hopefully I didn't significantly reduce the life of any of my appliances or audio gear during the time that it got really bad.


Hopefully your situation can be resolved easily.
 

KenOfCary

Board of Directors, Secretary
Ken
Staff member
Corporate Member
I'm hearing over an over that problems with electricity to the house/shop are most likely due to grounding problems or bad connections. The situation where I was in Virginia was that I was on the end of a line - I was the last transformer on that line as I was on the county border. There was never any problem with the supply. Once the ground rod was moved 8' out in front of the porch and tied into the existing ground rod under the porch everything cleared up.

As has been mentioned, our countries power grid is amazingly robust and the supply is consistent. If yours isn't get help to find out what the real problem is.

I spent a lot of money replacing electronic components until I called in the right people to deal with the problem, which cost me nothing. They fixed it for free, as they should have.
 
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