harmonic distortion damaging electrical items

racervette69

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Been losing power lately, wind mostly, drives me nuts.. How important is harmonic distortion? I've read to try to keep it around 7% and what comes from the power co is 3% Looking at a portable 10k generator and installing a manual transfer switch. Mainly wanting to keep the furnace fan, freezer and under ground water pump working . Most dont advertise their distortion. Any help from you EE's.
 
Been losing power lately, wind mostly, drives me nuts.. How important is harmonic distortion? I've read to try to keep it around 7% and what comes from the power co is 3% Looking at a portable 10k generator and installing a manual transfer switch. Mainly wanting to keep the furnace fan, freezer and under ground water pump working . Most dont advertise their distortion. Any help from you EE's.

Never heard of harmonic distortion on a power line, damn sure not see on a scope.....that is something that happens to a audio amp, and to destroy speakers/tweeters it really has to get into clipping, where the HFreq pulses from the clipped wave form greatly exceed the power handling capabilities of the tweeter array.....

I think your freq control is much more critical than most anything else....all household motors love 60 hz in this country....you get too far off that and they go nutz.....
 
Been losing power lately, wind mostly, drives me nuts.. How important is harmonic distortion? I've read to try to keep it around 7% and what comes from the power co is 3% Looking at a portable 10k generator and installing a manual transfer switch. Mainly wanting to keep the furnace fan, freezer and under ground water pump working . Most dont advertise their distortion. Any help from you EE's.

you're losing power bacause the wind is pushing tree limbs into the overheasd lines. Nothing to do with distortion. 3rd and 5th harmonics can exist on the power system induced by customer loads. It doesn't hurt anything.

10k generator? That sounds like a lot. I would think 4 or 5kw would be more than your need.
 
Been losing power lately, wind mostly, drives me nuts.. How important is harmonic distortion? I've read to try to keep it around 7% and what comes from the power co is 3% Looking at a portable 10k generator and installing a manual transfer switch. Mainly wanting to keep the furnace fan, freezer and under ground water pump working . Most dont advertise their distortion. Any help from you EE's.

Simple answer. Those appliances are fine with "dirty" power. As Gene has stated, frequency is the most regulated item. Clocks work off frequency, and rely on it for time. (This is why Edison does x-overs at midnight). My best advice is don't worry, buy one 20% larger than your total FLA load, and install a UPS unit on your computer. (They are the sensitive critters).
 
Been losing power lately, wind mostly, drives me nuts.. How important is harmonic distortion? I've read to try to keep it around 7% and what comes from the power co is 3% Looking at a portable 10k generator and installing a manual transfer switch. Mainly wanting to keep the furnace fan, freezer and under ground water pump working . Most dont advertise their distortion. Any help from you EE's.

you're losing power bacause the wind is pushing tree limbs into the overheasd lines. Nothing to do with distortion. 3rd and 5th harmonics can exist on the power system induced by customer loads. It doesn't hurt anything.

10k generator? That sounds like a lot. I would think 4 or 5kw would be more than your need.

Jim,you are a power company engineer, no, I remember right??

how in hell you going to get harmonics on a power line from any load???

:skeptic:
 
Here, we have a lot of experience with portable generators.

Suggest getting a Honda generator.
Has a better rated duty cycle generator, run a LOT quieter than others, most have auto idle circuits that save you a LOT of gas. I think their power is a little cleaner too. Check their websites
At worst get one with a Honda engine, very trouble free and great longevity.

Have seen a lot of problems with the cheaper, lesser quality ones. When your without power, you don't want problems.

Ours is a 7kw and it runs the 3ton a/c, plus refrig, plus the rest of the house at once, less the elec oven, elec water heater, and any other high draw pieces. If and when we need those, we just turn off the breaker for other high draws and use that item individually.

I just backfeed the generator into the drier receptacle in the laundry, turn off the main breaker and adjust other breakers as needed. I end up using a double male prong feed cord. This is exremely dangerous and illegal, but it has worked for years that way. Just didn't want to go thru all the hassle of wiring in a transfer switch, because one that handles all the circuits is very expensive and a real pain to wire in. It must match the whole main panel rating of the house if you want full options and not the generator output.
Thought about at least putting in one of these only lockable.
http://www.peakpowertools.com/Gen-Tran-50-Amp-Power-Inlet-Box-p/agt63651.htm
Then at least I couldn't have a potential 40 amp power cord with hot prongs.


Flame away :tomato: :rain:

Also, because of the winds here, a couple of times I have gotten unequal voltage on each leg into the main panel (70v on 1 leg and 160v on the other), ended up as a deteriorated neutral connection at the pole, power company came out and fixed immediately both times. Maybe because they use aluminum wire in all this salty windy air???
 
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If it's a huge problem you can get a whloe house isolation transformer. It will ensure the power delivery is clean and consistent.
 
I just backfeed the generator into the drier receptacle in the laundry, turn off the main breaker and adjust other breakers as needed. I end up using a double male prong feed cord. This is exremely dangerous and illegal, but it has worked for years that way. Just didn't want to go thru all the hassle of wiring in a transfer switch, because one that handles all the circuits is very expensive and a real pain to wire in. It must match the whole main panel rating of the house if you want full options and not the generator output.

I do the same thing. The generator is in the shed, I just put a 240VAC outlet out there and ran it back to the house. I shut the main and just fire the generator. works for me. The few times I needed it, it works fine.
 
Also, because of the winds here, a couple of times I have gotten unequal voltage on each leg into the main panel (70v on 1 leg and 160v on the other), ended up as a deteriorated neutral connection at the pole, power company came out and fixed immediately both times. Maybe because they use aluminum wire in all this salty windy air???

OUCH, that hurts....lucky you din't blow a bunch of crap.....long time ago a ham radio buddy turn his Tek scope on to the line, and saw a huge burst/bubble at the crossover point....bad ground.....he was having troubles with his ham gear, and so called the power company, they laughed and said 'how do you know we have a bad ground??'......he said, cause I have my Tek hangin on the line......

'Oh, we'll be right out'....


:goodnight:
 
Also, because of the winds here, a couple of times I have gotten unequal voltage on each leg into the main panel (70v on 1 leg and 160v on the other), ended up as a deteriorated neutral connection at the pole, power company came out and fixed immediately both times. Maybe because they use aluminum wire in all this salty windy air???

There should be a ground rod at your meter too. You could put one in easily.


If it's a huge problem you can get a whloe house isolation transformer. It will ensure the power delivery is clean and consistent.
If you want to waste a ton of money for nothing. Nothing in a residence is that sensitive or critical. It would be a potential source of other problems or creating a fire. I doubt NEC codes even allow for that in a residence.

I just backfeed the generator into the drier receptacle in the laundry, turn off the main breaker and adjust other breakers as needed. I end up using a double male prong feed cord. This is exremely dangerous and illegal, but it has worked for years that way. Just didn't want to go thru all the hassle of wiring in a transfer switch, because one that handles all the circuits is very expensive and a real pain to wire in. It must match the whole main panel rating of the house if you want full options and not the generator output.


I do the same thing. The generator is in the shed, I just put a 240VAC outlet out there and ran it back to the house. I shut the main and just fire the generator. works for me. The few times I needed it, it works fine.

That's what i do too. As long as the main is open you won't backfeed the primary.
 
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I understand you guys running a genny like that, however, I cannot condone it. Guys die every year from this, and it only takes once.
Be forewarned, if utility guys are out and hear these running, they do that area last, and take their time. Lives are at stake here. That code has a very clear reason for being there.
As for an iso tranny at a residence, I'm with Jim. It has very little value if at all, and just uses more energy.
 
Also, because of the winds here, a couple of times I have gotten unequal voltage on each leg into the main panel (70v on 1 leg and 160v on the other), ended up as a deteriorated neutral connection at the pole, power company came out and fixed immediately both times. Maybe because they use aluminum wire in all this salty windy air???

There should be a ground rod at your meter too. You could put one in easily.


If it's a huge problem you can get a whloe house isolation transformer. It will ensure the power delivery is clean and consistent.
If you want to waste a ton of money for nothing. Nothing in a residence is that sensitive or critical. It would be a potential source of other problems or creating a fire. I doubt NEC codes even allow for that in a residence.

I just backfeed the generator into the drier receptacle in the laundry, turn off the main breaker and adjust other breakers as needed. I end up using a double male prong feed cord. This is exremely dangerous and illegal, but it has worked for years that way. Just didn't want to go thru all the hassle of wiring in a transfer switch, because one that handles all the circuits is very expensive and a real pain to wire in. It must match the whole main panel rating of the house if you want full options and not the generator output.


I do the same thing. The generator is in the shed, I just put a 240VAC outlet out there and ran it back to the house. I shut the main and just fire the generator. works for me. The few times I needed it, it works fine.

That's what i do too. As long as the main is open you won't backfeed the primary.

Yes, late codes here in Florida are to have two grounding rods some 6-8? feet apart, for each house....I grounded my hot tub with it's own rod, same one my aluminum atrium frame is attached to....dedicated ground out back....

Yeh, I agree, your whole house is isolated pretty good via that thing on the poles, but having said that, I have a couple of nice heavy 1 kw isolation transformers I use for my stereo controls/inputs...but not the power amp....complete with surge strip on the output, same for my computer/router/modem here now....Florida is the lightening capitol of the nation, so they say....methinks they right.....:flash::rain:
 
I understand you guys running a genny like that, however, I cannot condone it. Guys die every year from this, and it only takes once.
Be forewarned, if utility guys are out and hear these running, they do that area last, and take their time. Lives are at stake here. That code has a very clear reason for being there.
As for an iso tranny at a residence, I'm with Jim. It has very little value if at all, and just uses more energy.

Please explain? During an ice storm a couple of years back, we were without power for 5 days. About 1/3 of the houses in my sub had generators. All of them portable backfeeding into the house in some way. I had mine going through the drier outlet. If the main is open, what's the risk? I'm not being a smartass here...I really want to know so that I don't end up croaked or croaking anyone of the utility workers.
 
Also, because of the winds here, a couple of times I have gotten unequal voltage on each leg into the main panel (70v on 1 leg and 160v on the other), ended up as a deteriorated neutral connection at the pole, power company came out and fixed immediately both times. Maybe because they use aluminum wire in all this salty windy air???

There should be a ground rod at your meter too. You could put one in easily.


If it's a huge problem you can get a whloe house isolation transformer. It will ensure the power delivery is clean and consistent.
If you want to waste a ton of money for nothing. Nothing in a residence is that sensitive or critical. It would be a potential source of other problems or creating a fire. I doubt NEC codes even allow for that in a residence.

I just backfeed the generator into the drier receptacle in the laundry, turn off the main breaker and adjust other breakers as needed. I end up using a double male prong feed cord. This is exremely dangerous and illegal, but it has worked for years that way. Just didn't want to go thru all the hassle of wiring in a transfer switch, because one that handles all the circuits is very expensive and a real pain to wire in. It must match the whole main panel rating of the house if you want full options and not the generator output.


I do the same thing. The generator is in the shed, I just put a 240VAC outlet out there and ran it back to the house. I shut the main and just fire the generator. works for me. The few times I needed it, it works fine.

That's what i do too. As long as the main is open you won't backfeed the primary.

Yes, late codes here in Florida are to have two grounding rods some 6-8? feet apart, for each house....I grounded my hot tub with it's own rod, same one my aluminum atrium frame is attached to....dedicated ground out back....

Yeh, I agree, your whole house is isolated pretty good via that thing on the poles, but having said that, I have a couple of nice heavy 1 kw isolation transformers I use for my stereo controls/inputs...but not the power amp....complete with surge strip on the output, same for my computer/router/modem here now....Florida is the lightening capitol of the nation, so they say....methinks they right.....:flash::rain:

The basic rule is 5 ohms or less to ground as read by a biddle ground tester. Usually, in very sandy soil, they make you add a second one 6' away. That is the general limit. I did one job close to the beach, and they made me use 2 3/4" x10' rods coupled together in two locations. That's two 20' rods with a rod coupling. Still showed up poorly, but he let it go per code.
Data jobs usually spec out chemical ground rods. They are 2" copper tubing filled with copper sulfate.When a 6" hole is drilled 10', the rod (tube)is inserted into the hole, and backfilled with salt and dirt. Salt water is then poured into the hole. The salt grows "roots", and you usually end up with less than 1 ohm to earth. The tube has a breather hole top and bottom. "They say" that differential barometric pressure aids in the salt root growth.
 
Also, because of the winds here, a couple of times I have gotten unequal voltage on each leg into the main panel (70v on 1 leg and 160v on the other), ended up as a deteriorated neutral connection at the pole, power company came out and fixed immediately both times. Maybe because they use aluminum wire in all this salty windy air???

There should be a ground rod at your meter too. You could put one in easily.


If it's a huge problem you can get a whloe house isolation transformer. It will ensure the power delivery is clean and consistent.
If you want to waste a ton of money for nothing. Nothing in a residence is that sensitive or critical. It would be a potential source of other problems or creating a fire. I doubt NEC codes even allow for that in a residence.

I just backfeed the generator into the drier receptacle in the laundry, turn off the main breaker and adjust other breakers as needed. I end up using a double male prong feed cord. This is exremely dangerous and illegal, but it has worked for years that way. Just didn't want to go thru all the hassle of wiring in a transfer switch, because one that handles all the circuits is very expensive and a real pain to wire in. It must match the whole main panel rating of the house if you want full options and not the generator output.


I do the same thing. The generator is in the shed, I just put a 240VAC outlet out there and ran it back to the house. I shut the main and just fire the generator. works for me. The few times I needed it, it works fine.

That's what i do too. As long as the main is open you won't backfeed the primary.

Yes, late codes here in Florida are to have two grounding rods some 6-8? feet apart, for each house....I grounded my hot tub with it's own rod, same one my aluminum atrium frame is attached to....dedicated ground out back....

Yeh, I agree, your whole house is isolated pretty good via that thing on the poles, but having said that, I have a couple of nice heavy 1 kw isolation transformers I use for my stereo controls/inputs...but not the power amp....complete with surge strip on the output, same for my computer/router/modem here now....Florida is the lightening capitol of the nation, so they say....methinks they right.....:flash::rain:

same here on the grounding rods. Thanks for the help, just did want to ruin my stuff. So dirty is not that big of a deal? Gillette generators advertise clean power. I think my well pump is 1.5 hp, lot of start up load? I did a calculation on how much I need continuous load. Just hope ever motor doesnt start at the same time...lol. Trees are down all around us. Got our fence in a few location. So far, cows are still in..
 
Christ, I HOPE those cows are in.....when I talk of bump stear on a car, I mean stear, I hit a COW once, wiped out the whole left side of my car.....damnit...:cussing::cussing:

as for grounding, I have some very funny stories from the metal detector daze in the early 80's....ungrounded NUCLEAR POWER plant.....and the lengths they went to ground the joint at Goodyear Atomic on the Ohio River.....

weird shit man....

:rofl::thumbs:
 
Also, because of the winds here, a couple of times I have gotten unequal voltage on each leg into the main panel (70v on 1 leg and 160v on the other), ended up as a deteriorated neutral connection at the pole, power company came out and fixed immediately both times. Maybe because they use aluminum wire in all this salty windy air???

There should be a ground rod at your meter too. You could put one in easily.


If it's a huge problem you can get a whloe house isolation transformer. It will ensure the power delivery is clean and consistent.
If you want to waste a ton of money for nothing. Nothing in a residence is that sensitive or critical. It would be a potential source of other problems or creating a fire. I doubt NEC codes even allow for that in a residence.

I just backfeed the generator into the drier receptacle in the laundry, turn off the main breaker and adjust other breakers as needed. I end up using a double male prong feed cord. This is exremely dangerous and illegal, but it has worked for years that way. Just didn't want to go thru all the hassle of wiring in a transfer switch, because one that handles all the circuits is very expensive and a real pain to wire in. It must match the whole main panel rating of the house if you want full options and not the generator output.


I do the same thing. The generator is in the shed, I just put a 240VAC outlet out there and ran it back to the house. I shut the main and just fire the generator. works for me. The few times I needed it, it works fine.

That's what i do too. As long as the main is open you won't backfeed the primary.

Yes, late codes here in Florida are to have two grounding rods some 6-8? feet apart, for each house....I grounded my hot tub with it's own rod, same one my aluminum atrium frame is attached to....dedicated ground out back....

Yeh, I agree, your whole house is isolated pretty good via that thing on the poles, but having said that, I have a couple of nice heavy 1 kw isolation transformers I use for my stereo controls/inputs...but not the power amp....complete with surge strip on the output, same for my computer/router/modem here now....Florida is the lightening capitol of the nation, so they say....methinks they right.....:flash::rain:

same here on the grounding rods. Thanks for the help, just did want to ruin my stuff. So dirty is not that big of a deal? Gillette generators advertise clean power. I think my well pump is 1.5 hp, lot of start up load? I did a calculation on how much I need continuous load. Just hope ever motor doesnt start at the same time...lol. Trees are down all around us. Got our fence in a few location. So far, cows are still in..

Start up is generally 6 times FLA. However, it tapers down so fast, we use 25% head room as a margin. When gennies are automatic, the transfer is delayed untill they stabilise, then they connect. The genny has to able to start all loads at once, or load shed, or stagger start, or only operate "necessary" circuits.
If you are doing this manually, just connect, start, wait 60 seconds or so, and gradually add loads. You'll be fine with your total desired load plus 25%.
Here is the last genny I hooked up. 2,000KW/480V/3 phase. (That's a 10'ladder in the dark)
3495d594449a37.jpg
3495d594533df1.jpg
 
Also, because of the winds here, a couple of times I have gotten unequal voltage on each leg into the main panel (70v on 1 leg and 160v on the other), ended up as a deteriorated neutral connection at the pole, power company came out and fixed immediately both times. Maybe because they use aluminum wire in all this salty windy air???

There should be a ground rod at your meter too. You could put one in easily.


Have a good ground rod per code 5/8" x 8ft copperclad with teardrop and #4.
Both times it was their neutral at the pole connection.

Surprising we don't have the dual rod thing down here because we are 100% sand everwhere. But they are very strict on the extra bonding here for pool decks, screen enclosures fences etc even all motors and appliances. I know they don't like separated ground rods called it "jumping grounds" or something.

Lightning did hit a tree out front once, blew the ground clamp off the rod, blew every low voltage lite fixture in the house, blew the garage door opener, destroyed four fairly new tires, alternator, electronic speedo, big chunk of concrete out of driveway, and finally killed the mohogany tree next door. All this was long after my neutral issues.
 
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