Generator sizing

[Lutfi]

I am a structural engineer who is in search of software of spreadsheets that are used to size generators.

If you can give me a link to such site, I would be grateful.

Regards,


Lutfi

http://www.cdeco.com

 

[mpparent]

Lutfi,

Rather than do it yourself, I'm sure a local rep. would be glad to help you size your gen. There are many things to consider, such as type of loads served, voltage dip allowable, etc.

Mike

 

[Lutfi]

mpparent,

I appreciate your input. I have been doing so for the larger ones. What I was looking for is excel spreadsheet that I can use personally. I found some stuff on the Internet that was useful.

Thanks for your input.


Lutfi

http://www.cdeco.com

 

[ctpt]

There is a software "Electric Power Quicksize" available form caterpillar which may be helpful.

http://www.cat.com/cda/layout?m=37508&x=7

 

[rbulsara]

I think the best advices are already given in the above posts..

If the load is small enough and no large motors its simple arithmetic to add the loads, this assumes you will be able to even out the load each of the three phases of a 3-phase generator or a single phase 3-wire unit, plus allow for some imbalanceand growth.

However if you do not understand the single phase loads and three phase generator relationship or a single phase 3-wire system, you are better off getting help of a electrical engineer friend.

For whatever it is worth look up, my faq237-766 if majority of the load is motors.

 

[mc5w]

You can also get data from

http://www.cumminspower.com

as to the motor starting capability of their generator sets. Their ratings are for code G motors and 10% voltage dip. For their larger generators they have a permanent magnet exciter option which is the only thing that you should get if available.

Basically, Marathon Electric ( which is the company that really makes tha alternators ) make 3 different grades of 3-phase and 4 different grades of single phase alternators. the bottom grade of 3-phase and the 2 bottom grades of single phase alternators are basically lighting generators that have very little motor startin capability.

Also, when running off of a local generator any motor that is larger than 3 Horsepower needs to be 3-phase driven by a 3-phase generator. You could buy a big genset that is oversized enough but if you have a bunch of 5 to 10 HP motors what you need if you are stuck with single phase utility power is a single phase to 3-phase converter. Indeed, some farmers have a big 3-phase generator to run the big loads because for how long they use those loads versus power failures they will get more utility out of the genset than out of a phase converter.

I also one time was in a machine shop south of Akron Ohio that used a 3=phase generator rather than utility power even though there was 4-wire primary line out front. The genset was cheaper than paying Ohio Edison $15,000 to put up a transformer and then paying 16 cents per kilowatthour!

 

[ScottyUK]

In Europe at least, Cummins use alternators made by Newage. I'm not sure about the US machines - maybe they are made by Marathon. Cummins usually keep most things in-house, like Onan electronics and Newage alternators, and publish very little about the 'black boxes'.



----------------------------------

If we learn from our mistakes,
I'm getting a great education!

 

[davidbeach]

Most Cummins engine-generator sets constructed for the North American market use Newage alternators.

 

[Lutfi]

Many thanks for the feed back friends. I think it was worth while to post on this forum.

If you ever have a structural, feel free to post on structural and I will be most happy to help.

Regards,


Lutfi

http://www.cdeco.com