Connecting an induction motor to the grid? [LOCKED]

[ArmedAndDangerous]

I am planning on building a natural gas cogeneration setup on an experimental basis. What is the proper equipment one needs to buy in order to correctly tie into the grid with an induction motor? Some kind of UL approved switch or whatever to turn off power when the grid fails or it goes out of phase...what is normally used?

Armedanddangerous stepped on his dick in this thread by being arrogant and combative [see #27 and about 7 others below]. He is no longer able to post so this thread is closed to further comments.

[Flux]

I can't help, I am not familiar with your regulations but in theory there is no difference between a motor and an induction generator. In general utilities don't encourage generation and they may impose serious restrictions. If the mains goes off it will fail to generate unless you have local power factor correction. This may be an issue that the utilities may be worried about and may ban PFC or demand a lot of things to shut it down under these conditions.

Don't worry about going out of phase, it is an asynchronous generator and will operate at slip, it doesn't work like a synchronous machine. You can overload it and pull it through its torque curve. You may trip breakers on the way but if it does pull out it will produce little torque and the engine governors should hold things safely.

Probably need to contact your utility to see what their local requirements are, I think they all have different idea depending how much they want to discourage you.

Flux

[ArmedAndDangerous]

My local utility is good about buying back the power, however, everything has to be inspected and up to code, etc. As long as I can setup the equipment correctly they will come install a backwards reading meter for free.

But there must be some sort of UL approved switching device to interconnect an induction motor to the grid, I know this is common practice. Sort of like a transfer switch, but different...

[wdyasq]

As Flux stated ... "your local utility" is the FIRST identity you have to deal with. Your state may require somethings. As you have given the board a lot of information to work with ...

I think I would use copper wire.

Ron

[ArmedAndDangerous]

The utility is a NON ISSUE. They will buy it back, period. If I were to ask them how to hook up an induction motor, they would tell me to call an electrician, which I will not.

I know there are plenty of people here who have connected induction motors to the grid. How did you do it? Surely there must be some kind of UL approved switching apparatus to disconnect my generator if the grid fails.

[vawtman]

Oh Boy you are dangerous but thankfully not armed yet.Kiddin but serious.

[TomW]

Dangerous;

 If I were to ask them how to hook up an induction motor, they would tell me to call an electrician, which I will not.

Funny, you refuse to hire help but will take a real risk listening to "free" online advice from folks who will bear no responsibility should it be bad advice?

Some stuff you really should not undertake unless you have a clue. One reason I refuse to advise folks who obviously are not aware of the pitfalls and issues in a dangerous undertaking. This does not sound like RE to me, either since running an AC motor in the "sweet spot" for grid backfeed is not a trivial task with a natural power source.

Its your project so why not bite the bullet and hire someone with a clue before you take bad

advice for "free"?

Think about it. Sometimes cost needs to take a back seat to practicality. Just from how you worded your question and replies it is clear you should hire someone or get onto educating yourself.

A quick Google search for "induction motor alternator grid tie" would probably find every scrap of info you need. But thats another rant.

Just my opinion and may not be shared by all.

Honest opinion and I tried to be nice and not say "you fsking idiot, hire help, you need it".

TomW

I just don't get it. At all.

[ghurd]

"They will buy it back, period."  

I think that's now a law. Maybe not. No matter because it doesn't really matter.

However.  

They can require UL approval on every piece for the use it is being used. A motor may have UL listing as a motor.  A motor isn't going to have a UL listing as a gen.

They can require a licensed (and UNION) electrician to do anything new connected to the grid (like here).

They can charge you extra to read an extra meter (the sell back meter) more than you ever hope to save.

They can give you a tiny amount of money or credit for the power you made. Like wholesale or less.  And still charge you extra to read the meter.

They can have the inspector just flunk it, and (here) you have no recourse. He is God.

If you don't know how to do it already, it would be best to have someone who understands it completely figure the system out.

"call an electrician".  Doubt it.  Call a certified licenced insured bonded EE etc firm, that we approve? Maybe.

It will still be "an experimental basis" waste of cash.

G-

[thefinis]

No the utility is the main issue. They will have the codes you must abide by like the auto cutoff for power outages some require lockable switches. Some utilities require over and under voltage and freq switches to cut the connection if your voltage or freq deviates from a set range. Most require UL approved setups some require it either be installed by an electrician or inspected by one some may even require an engineers approval. Most if not all require a large libality insurance policy that will cover any damages or injuries that may be caused by your installation. They should have an interconnect agreement which will have their requirements in it.

Basicly though you need a steady set rpm @ the same percentage over the rated rpm as the normal slippage probably 3-5%. In your case with a gen-set powered by a steady power source you need a way to regulate and hold a set rpm.

Do a search for induction generators here to see any of the many threads that have covered this but be warned most start down this road only to find it filled with legal and financial pot holes and give up.

[thefinis]

Dang I was too slow.

Lots of good advice take it and do some more research.

Fiois

[JimB]

Over on the utterpower site they have a book available that is written by someone experienced with such a thing. I have read it and it contains much technical info and disclaimers. It would be a good place to start getting the info you will need. Good luck.

[electronbaby]

Just because many have done it does NOT mean that it is safe. YES, all utilities that allow net metering have a "utility interconnection agreement". The system must be protected to UL1741 in north america. The AHJ is god, and you must abide by their rules. I agree with everyone here in that you MUST know what you are doing before you injure yourself and quite possibly others. The regulations and code you must follow to do this safely are in place for a reason. If you want to do this anyway, dont tell us about it. I wont be held responsible if you kill yourself or others. Keep in mind, the grid will always win, and you run the risk of damage to your equipment or human life.

Just my two cents. This is a serious issue.

[jonas302]

almost seems best to make it self exciting and run it though a grid tie inverter just like a solar system?

[electronbaby]

bingo. If you do it right you can sweep MPPT of your dc gen and vary the rpm of your engine to save fuel. I know nothing.

[ArmedAndDangerous]

Christ! You guys take a simple question and try to make it sound like I'm killing puppy dogs.

I KNOW it has to be UL and utility approved and inspected. I stated that in my first post. I do not need an electrician to do it because I can do it myself and then have the electrician inspect it. It is NOT danerous in any way to do this with UL approved equipment and an inspection.

That said, if the REQUIREMENTS are to use UL approved switches, that means UL approved switching equipment must be manufactured by somebody. What type of switching equipment do I need and where can I buy it?

[ArmedAndDangerous]

That would be nice...if I had an extra $4,000 to spend.

[ArmedAndDangerous]

Tom, it clearly says above where I am typing now "Please be nice. Flame wars and rude comments are NOT tolerated here, and the offending comments will be deleted immediately."

As a moderator here you should know that, not to mention abide by that.

With that said I will respectfully ask you not to post further in any of my threads. Every comment you've left for me is rude, I won't tolerate it.

[Flux]

Try a Google search. Only a few who have done this will be able to help you.

As others have said, approval for a motor doesn't mean approval for a generator.

Why not contact manufacturers of motor starting switchgear, they may help with basic contactors and overloads. All other equipment for sensing frequency and voltage deviation for shut down will be specialised and the demand is so limited that few will ever take the trouble to design this sort of thing and get certification.

I am certain there is a supplier somewhere that specialises in this limited market. I am equally sure that if anyone here knew of them or had dealt with them they would have given advice immediately.

Your user name doesn't inspire anyone to be very helpful and your attitude to people generally will not bring you much help. Nobody is withholding this information, it just happens to be too specialised and not a common requirement.

Flux

[ArmedAndDangerous]

Actually, TomW specifically said he refuses to answer the question. No matter, I don't want his advice anyway. I've searched and searched on this board and google and seen dozens of people talk about how they hooked an induction motor up to the grid. Are they all doing it illegally? Does anybody make induction generators specifically designed for grid connection?

If someone here doesn't know the answer to the question, that's fine, they don't have to reply. But leaving stupid comments, calling me clueless, and telling me "if you don't know don't do it" is rude and and ridiculous. You tell me to do more research...what the *@%& do you think this post is for? Gathering information.

[DamonHD]

You are rude and arrogant and ungrateful and idiotic.

People are pointing out the LAWS and the DANGERS.

If you consider that bad then you really need your head examining.

No one is under ANY obligation to help at all.

And please try to not kill other innocent bystanders while grandstanding.

Something about "not big and not clever" springs to mind.

Rgds

Damon

[Flux]

" Are they all doing it illegally? "

I expect most are! Fortunately if you have basic knowledge and don't power factor correct there is little danger, but things can still go wrong under odd load conditions.

One idea may be to contact manufacturers of smaller commercial grid tie wind turbines. many of these use induction generators. They may not sell you what you want but could possibly point you in the right direction for information.

Induction generators are rarely used outside the wind industry and in general small power generation to the grid is rarely cost effective so few people do it. No doubt there are people offering combined heat and power systems with synchronous alternators and again they may be able to point you to something. The approval may be different but the basic problems are similar. In fact the synchronous machine is more problematic as it will not stop generating with loss of line volts.

This is basically off topic for most people here trying to produce power in remote places. I don't think Tom was unreasonable, if you got what you want here fine but no need to be aggressive when you don't get free advice in the form that you want. Sounds like a commercial project being done on the cheap.

Flux

[oztules]

Hi A&D

Yes the folks here have their days and crusades. Sad but true.

It would appear that there is scant sensible information forthcoming from this board on this subject, for reasons I don't understand.

There is much ado about regulations, but that is something to sort out with your power provider, not us.

Islanding is necessary in relation to safety, and MUST be done to the satisfaction of your provider... not us.

Power quality is between you and your provider... not us again.

Sadly I don't know how to advise you on the subject of what to buy or procure either... however

This link is to a bunch of guys who see it more sensibly than most of the respondents here.

http://www.prairieturbines.com/

For the price of their book, they apparently walk you through the entire process, including I believe, helping with approvals information relating to your provider.... (ask them first ......this could be a crock on my behalf where I haven't understood their waffle properly..... happens..)

Good thing you didn't ask out of curiosity how an atomic bomb worked....

If you get it happening, it would be interesting if it was as impossible as has been peddled here by the rabid lynch mob that has beset you.

Good luck with your project.

.......oztules

[TomW]

And your point is?

My point is you obviously are not equipped to do this without help and therefore you should go hire help. How is that my fault? I guess cheap, clueless folks find honesty to be "rude"?

Being an admin does not gag me. I will post what, when and where I wish and your whole 6 months of membership does not give you any right to resterict me in doing that.

I may ask you to grow up and accept honest opinion and advice in the manner it was given.

If you wish to request a refund of your cost of posting here, I will expedite its' processing.

You are welcome.

Now, since I had a half dozen folks agree with my point are you going to demand they not post in your threads?

Get a clue, grow up and stop deciding things based on childish misconceptions you hold. Just your nickname told me all I need to know about you. Go figure.

T

[Flux]

Prarieturbines is certainly a good starting point, they use an induction generator. Probably the smallest around and likely to be about your size.

Flux

[joestue]

My residential utility has a 20 hp restriction on any type of motor, for a 200 amp service. I suspect your's will have a similar restriction, and they won't be able to tell the difference between a motor and generator, because it could potentially be used as both.

An induction motor of say 20 HP should not cause any "islanding" and I would speculate that the only gear you need is some type of UL approved grid failure cutout box.

Of course the issue is how "stiff" is the grid, and all the remaining "what if..."

[ArmedAndDangerous]

You are stupid and you smell like a goat.

I did not ask about laws or dangers as I already know them. The simple question was what equipment do I need to buy in order to be SAFE and LEGAL. A few people tried to help, but most just put their foot in their mouth.

[ArmedAndDangerous]

To flux and others who have actually tried to help, thank you. Obviously this thread is dead and too many users here are clueless so I will find my advice elsewhere. This board used to be a great place to ask questions and learn things. I've been here a hell of a lot longer than "6 months". It is sad that it has turned into this kind of BS with a jackass moderator in charge who can't obey his own rules.

"I would speculate that the only gear you need is some type of UL approved grid failure cutout box."

Yep, that's all I really needed to know. A very simple question that for some reason caused everyones panties to wad up an initiate a serious hissy fit.

[ArmedAndDangerous]

Tom, you're an idiot, and an asshole, pure and simple. You have NO idea what my knowlege on this subject is. Judging me by my name is absolutely ridiculous. Not just towards me, but nearly all the comments I've read from you are rude, condescending, and unhelpful.

As you would say, go fv(k yourself.

I'm sure you'll try and ban me for this, but that will only further prove what a hypocrite you are. Don't think for a second that I can't go sign up again as many times as I want.

PS - IP bans don't work either.

[TomW]

Goodbye and enjoy your quiet time.

[ghurd]

Sorry to everyone except A&D.  This is Really bothering me.

A&D should notice there is not a single question to answer.

"they would tell me to call an electrician, which I will not."

Lots of electricians on this board. And I expect they are a cut above the rest.

I know a lot of electricians, and bet they would call me if they wanted to try something like this.

Lots of EE members too.  And at least one former inspector.  

Plenty of BAs, BSs, MAs, PhDs, MDs.  Some I consider the best have no credentials of which I am aware.

"If someone here doesn't know the answer to the question, that's fine, they don't have to reply."

They told you what to do in no uncertain terms.

"I KNOW it has to be UL and utility approved and inspected."

The question means "What will my un-named utility approve?".

"I've searched and searched on this board and google and seen dozens of people talk about how they hooked an induction motor up to the grid."

Then read what they wrote.  Waiting for Spielberg to do the movie will take a while.

"I did not ask about laws or dangers as I already know them. The simple question was what equipment do I need to buy in order to be SAFE and LEGAL."

You already know the laws, but ask about the legal stuff.

You already know the dangers, but ask about safety.

"That would be nice...if I had an extra $4,000 to spend."

Like Flux said, it won't be cheap.

You were told before, more than once, the entire concept would lose money, in great quantity.  

If there is no hope of an extra $4,000 to spend, consider doing something that will save money instead of waste it. ("I like to drink beer".  Me too, but I can afford it.)

"too many users here are clueless"

You do not understand a widowmaker cord or how an inverter works or why inverters can't be seriesed or what a breaker does or why the natural gas cogeneration setup idea is still a money,

or why 9/19/07 to 3/17/08 is 6 months.

"PS - IP bans don't work either" and "Don't think for a second that I can't go sign up again as many times as I want"

combined with "users here are clueless"

certainly makes people wonder why anyone would sing up under a different name to get information from clueless users.

"telling me 'if you don't know don't do it' is rude and and ridiculous."

I didn't even notice until now, but that was taken out of context, and directed at me.

I assure everyone it is not the reason this bothered me.

I expect people would have offered more help if you hadn't shown a tendancy to fly off the handle (if you bothered to reply).

A selection of my favorites from other posts...

(it would certainly be longer, but the selection is slim with only 22 posts... 6 months, 17 comments, 8 stories, no diary, and empty files.)

"The thought that this is going to somehow kill a lineman is absolute stupidity."

"I own the wiring, I'll do as I damn well please with it, it's not the power company's business if I'm not using their power."

"Christ! Do you guys have a clue what a circuit breaker does?"

"I like to drink beer and play with engines."

Sorry TW.  I heard you are ill.  I know you read every word, even when ill.

Sometimes I can't help myself.

You have my support 215% (that is this one, another, and 15% of a 3rd that you can choose at your lesiure).

G-

[TomW]

Appreciate the support, G.

A&D committed fieldlines suicide yesterday.

Poor fellow.

Anyway, off to my clueless hidey hole. Shaking off this flu or whatever faster than my wife is.

I think we need to raise the bar here to getting an account to slow this stuff down. Thats another rant, tho.

TomW

[DamonHD]

A real life example of a little knowledge (and a great deal of pompous self-importance) being a dangerous thing, especially to a linesman nearby...

Rgds

Damon

[elvin1949]

All

 To top it all off.I KNOW A LINEMAN WHO DIED OVER THIS SAME THING.

 Sorry for yelling

later

Elvin