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Generators & Electric Motors General Discussion

Generator Parts and Frequently Asked Guestions


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  #1  
Old 03-20-2010, 05:36:37 PM
Chainsawman1 Chainsawman1 is offline
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Default Generator Parts and Frequently Asked Guestions

I was just thinking about the last post and I think that this should be added to frequently asked questions list.
(WHAT YOU DO NOT DO AT ALL.) Becouse people could get killed or hurt.
All the smart guys know this but some do not.
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  #2  
Old 03-20-2010, 07:01:53 PM
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Talking Re: Generator parts and frequently asked questions.

Great, Write Something Up, and eMail it to "Me" and I'll see if we can make it a Sticky at the Top of a Forum Page, with the appropriate Title, or If ANYONE else would like to write something up, I will consider it for a Sticky....
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  #3  
Old 03-20-2010, 07:10:51 PM
Chainsawman1 Chainsawman1 is offline
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Default Re: Generator parts and frequently asked questions.

Good Idea I will.
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Old 03-20-2010, 07:19:25 PM
Isaac-1 Isaac-1 is offline
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Default Re: Generator parts and frequently asked questions.

The thing is there is a lot of stuff people do and get away with all the time, like test running a generator that is not grounded. If this is going to be limited to transfer switches it opens up a whole can of worms with the NEC and separately derived sources, grounding regulation, etc. All of which is so confusing that the electrical inspectors rarely have a grip on it, leaving the standard advice as call your local inspector and do it the way he wants. If that is not bad enough you then get into sub-panel transfer switches, whole house switches, safety interlink kits, and then some of these oddball meter base switches, etc. I guess what I am getting at is it is much easier to say USE A TRANSFER SWITCH than actually doing it.

Ike

Last edited by Isaac-1; 03-21-2010 at 01:18:43 AM.
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Old 03-20-2010, 09:16:58 PM
Chainsawman1 Chainsawman1 is offline
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Default Re: Generator parts and frequently asked questions.

True but to backfeed from a 120 line to the main is as you know (Is bad)
If you dont have ie the meter out or lock the main breaker in off or something.
I sent out some eMails to some of the smart guys from here to see what thay think....But for someone to get well you know...(DEAD) Is not good.
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Old 03-21-2010, 10:43:44 AM
armandh armandh is offline
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Default Generator parts and frequently asked questions.

to make the whole bonding issue simple.........
correct bonding makes it impossible for a point of failure in the return path to create a hazardous condition.

for 120/240 single phase house setup

a 3 wire 120/240 back feed is the WORST possible choice

SECOND WORST two 120v grounded cords back-feeding doubles the neutral and ground.

half the risk but still a major risk. both illegal

a separate neutral and ground [four wire connection] along with proper bonding is the lowest risk.

when installing a transfer device your main panel is no longer the first disconnect and [like all sub panels] must be converted to an isolated neutral.

a two wire transfer will not do if the generator power must be bonded at the generator.

transfer of the neutral may be necessary to maintain correct bonding.

a licensed electrician experienced in generator instillation is a must.
the cheapest life insurance you will ever buy!

where back-up power is required automatic transfer is required.

not required but nice to have back-up power ....

a permanently installed back-up generator requires a transfer device.

a portable generator requires a means to prevent inadvertent connection of the generator and mains.

[these are sorta "big picture" explanations]
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Old 03-21-2010, 11:46:55 AM
Chainsawman1 Chainsawman1 is offline
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Default Generator parts and frequently asked questions.

BTpost...Mod.
I like armandh's sticky and think it should go up top and have a good heading.
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Old 03-22-2010, 10:27:11 AM
cornbinder89 cornbinder89 is offline
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Default Re: Generator parts and frequently asked questions.

Quote:
Originally Posted by armandh View Post
to make the whole bonding issue simple.........
correct bonding makes it impossible for a point of failure in the return path to create a hazardous condition.

]
OK, to a layman, I am haveing trouble following this. I know your not supposed to have more then one bond point.... But, again to a layman, when you open your breaker panel in your house, you see all the nuterals and grounds tied to the same strip. I'm haveing trouble grasping the concept that more is worse then one. If the gen was grounded, the house or other end user grounded with a seperate ground rod, why is this more dangerous then a single ground point with both the nuteral and grounds connected? If I understand why it helps make sure I do it right all the time.
It seams with a single bonding point, a single failure would lead to no grounding and a "floating" nuteral... Am I wrong?
A transfer sw without a nuteral switch could back feed the grid if the ground is lost (do I at least have this correct?) and as such nuterals should be disconnected from the grid when back up power is used... But why the issue of a single bond point?
HELP!!
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Old 03-21-2010, 01:50:22 PM
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Talking Proposed new Sticky FAQ: Comments requsted from Resident SmartGuys

To all our Resident SmartGuys:

It has been proposed that we add a Sticky FAQ to the Main Motor & Generator Forum that deals with "Connection of Home Backup Generators to Homes and Home based Operations".

We believe that this should cover at a minimum
1. How NOT to do this, and why....
2. A few examples of How to Do this, and why....
3. A simple, and understandable primer on Neutral/Ground Bonding
4. A simple Statement, that one should consult with their local Inspection
Authority, BEFORE deciding on any one method or implementation.

I think that if we can get something understandable and informative, it would be a Very Good Thing to have. So, if we can all do some thinking about this, and come to a reasonable consensus I will get the results, Posted.

As appropriate Comments or Discussions are made in the above thread I will Bring them over to this Sticky FAQ

Bruce in alaska Asst: Chief Moderator SmokeStak.com
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  #10  
Old 03-21-2010, 01:53:48 PM
Isaac-1 Isaac-1 is offline
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Default Re: Generator parts and frequently asked questions.

Armandh, I think you have a lot of good information there, but I think something needs to be added in explaining why people should not backfeed. Just saying could kill a lineman is not as good as explaining that transformers are bidirectional and that little 120/240V department store generator would have its output voltage bumped up to 13,800V ? for whatever fraction of a second it took to zap a lineman miles away. Also in the last couple of years between dealing with generator stuff at work, and a residential install for my mother's house I have talked with probably a dozen electricians about generator/transfer switch installations around here, out of them about half had little experience in the matter, the other half had installed many generators. The thing that worried me is not a single one of these experienced installers (including one that that is the local dealer for one of the big name brands) had a good grasp on the grounding/bonding requirements. The one I ended up going with for my mother's house (and had to wait 6 months for a break in his schedule to do this "little job") insists that the correct way to install is with solid neutrals and the frame bonded and grounded at the generator.


Ike

p.s. note I live in an area that just recently adopted the NEC and does not yet have inspectors in rural areas
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Old 03-21-2010, 02:13:57 PM
Wayne 440 Wayne 440 is offline
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Default Re: Generator parts and frequently asked questions.

Unfortunately, not every electrician/inspector is going to interpret the NEC in the same way, nor is there a 100% chance that (even if he/she can quote the NEC word for word) the install will be compliant. There are many linemen/electricians and inspectors that will look at the requirement for neutral/ground isolation and transfer of the neutral conductor, make an odd face then say something along the lines of "why the #$%^ would you want to do that? That is the stupidest $%^& thing in the world..."

I ran into this years ago when I did my install, and still hear it today.
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Old 03-21-2010, 02:15:51 PM
Chainsawman1 Chainsawman1 is offline
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Default Re: Generator parts and frequently asked questions.

Isaac-1's post is very good to.
I think it should be added to.....(Sticky)
(THINGS TO DO AND THINGS NOT TO DO)
Before you run your genny!!!
And not to be morbid but I think the words kill dead and hurt should be in it.
Why? becouse it can happen!!!!
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Old 03-21-2010, 03:25:44 PM
Isaac-1 Isaac-1 is offline
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Default Re: Generator parts and frequently asked questions.

It should be mentioned that in some areas the power company will subsidize or perhaps even install meter base transfer switches.

Ike


p.s. I have also heard of electrical companies only allowing certain brands of transfer switches for home use, usually the one they sell.
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Old 03-21-2010, 03:39:05 PM
armandh armandh is offline
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Default Re: Generator parts and frequently asked questions.

why is it so confusing?
because no two are exactly alike and enforcement requires rules

our city installed a new "whole service" generator to replace the emergency panel service.

5 wire 208 3 phase


the large main panel including adjacent first sub panels had a single large buss bar for the bonding point. the main panel [mains] buss bars were hot off the meter CTs subs were after a disconect.

the new [tank under enclosed] gen was mounted outside with conduit to a wearher proof outside transfer system [easy service access] on the outside wall near the main/first sub pannels
a large fused disconnect on the mains buss was routed to the transfer system.
the output of the transfer was routed to the first subs buss.

all other disconects and the old emergency sub transfer feed were moved to the first sub [now post transfer buss] leaving the main buss feeding only the transfer.


this single point of bonding that included the mains disconect and the post transfer distribution, side by side would have driven the rule makers nuts.

but it was safe and a single point for all the neutral and earth connections.


there is no easy way to explain it for every case!
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  #15  
Old 03-21-2010, 05:24:36 PM
Isaac-1 Isaac-1 is offline
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Default Re: Generator parts and frequently asked questions.

Armandh, I understand there are complicated situations (mine so far have not been exactly typical with things like CT meters, multiple building connections with no central disconnect, etc), I know the NEC is not an instruction manual, but would it kill them to include an example of a simple home transfer switch install given there is so much confusion with inspectors. Maybe even one for a whole home switch and one for a sub-panel type switch.

Ike

p.s. Should we mention anything about the new NEC 2008 702.5 requirement for the generator to be sized for the max load when an automatic transfer switch is used (example a 200 amp whole house automatic switch must be connect to a generator of at least 48KW). Personally I think this one is insane, but it is in the latest NEC.

Last edited by Isaac-1; 03-21-2010 at 06:47:06 PM.
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Old 03-21-2010, 07:16:15 PM
Chainsawman1 Chainsawman1 is offline
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Default Re: Generator parts and frequently asked questions.

What is a (CT) Meter. Current transformer?
Want to make shure Im on the same page....TY
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Old 07-23-2018, 11:22:41 AM
ThorPowerUnits ThorPowerUnits is offline
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Default Re: Generator parts and frequently asked questions.

I have a 5.5 KW generator head and am looking to use an electric motor to turn the generator/alternator
If a 5.5KW generator is 5500 Watts and 1 Horsepower is 746 watts, this means I would need 7.37 Horsepower to get the 5.5Kw. Not much left over. If horsepower is always good even if you don't intend to use it, should I get a 10 HP electric motor?

Also to run the 10 HP motor I will be using 12 volt batteries. Will I need a bank of 6 batteries to keep it spinning at 1800 RPM?

The batteries will be charged by solar panels.
Thank you in advance for your imput...
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