Author Topic: Power factor - getting full power from a generator and maximizing efficiency  (Read 20388 times)

Chris R

  • Jr. Member
  • **
  • Posts: 54
    • View Profile
Re: Power factor - getting full power from a generator and maximizing efficiency
« Reply #30 on: September 18, 2012, 03:15:33 AM »
Thanks guys. Will order the rodger's book
Bob Thanks for confirming what I thought, PF of 0.8 would be better.
So with my Lima Mac with PF of 1.0 do I add some capacators?  Or just leave things alone? The lima Mac is bulit like a brick shit house. Big heavy (With aluminium frame) and does not get very hot.
BTW what is the PF on most of the ST units people are using?
Regards

dieselgman

  • Hero Member
  • *****
  • Posts: 3189
    • View Profile
    • Lister Parts
Re: Power factor - getting full power from a generator and maximizing efficiency
« Reply #31 on: September 18, 2012, 03:18:45 AM »
What rated size Lima MAC and what input horsepower? Are you using it in a 3-phase configuration?

We have always found the Marathon stuff to be very conservatively rated... can't necessarily say that about the other makers - especially Chinese generic ST stuff.

dieselgman
« Last Edit: September 18, 2012, 03:20:32 AM by dieselgman »
ALL Things Lister/Petter - Americas
Lyons Kansas warehousing and rebuild operations

mobile_bob

  • Administrator
  • Hero Member
  • *****
  • Posts: 2940
    • View Profile
Re: Power factor - getting full power from a generator and maximizing efficiency
« Reply #32 on: September 18, 2012, 03:25:05 AM »
the ST heads are all pf 1.0 and are known as "lighting" generators or "light plant" generators
however there may be some that are rated otherwise, i am not aware of any.

don't add capacitors until you get an understanding of pf, its measurement, and its correction.
you can burn things up in a hurry!

the capacitors are generally added at the load and in very specific amounts computed to correct the power factor to near unity, by near unity i mean pf 0.95

generally folks quit at pf 0.95 because , if you over correct the voltage will climb and burn out either the load or damage the generator... so you don't want to just throw some cap's at it without knowing whats going on.

wait for Bill's book

i bought the first book that came out of the first shipment of books from George several years ago... i bought the book for one reason and one reason only... that was the discussion of power factor and it correction from a practical standpoint... all the rest of the book was just icing on the cake for me.

bob g
otherpower.com, microcogen.info, practicalmachinist.com
(useful forums), utterpower.com for all sorts of diy info

Chris R

  • Jr. Member
  • **
  • Posts: 54
    • View Profile
Re: Power factor - getting full power from a generator and maximizing efficiency
« Reply #33 on: September 18, 2012, 03:39:55 AM »
Again Bob Thanks. My motto is if it aint broke don't fix it. So I was not planning on doing anything until I know more on PF.
Dieselgman. The Lima Mac is now configured for 120 volt only The VA HP is 7.5 HP/850 RPM (aircooled 8/1) and was originally speced at 4.25 KW with the original Genhead VS 4.5KW for the 8/1 . It was the Fat boy unit now dead and being used as a mooring in the Sea of Abaco, Bahamas.

dieselgman

  • Hero Member
  • *****
  • Posts: 3189
    • View Profile
    • Lister Parts
Re: Power factor - getting full power from a generator and maximizing efficiency
« Reply #34 on: September 18, 2012, 04:53:41 AM »
The LIMA was originally rated at what output?  Double Delta single-phase (120volt as stated) is the most reliable and robust way to wire that head and if it was originally rated at 5kW (most likely) then you will never get near an overload/overheat with your VA at 7.5 horsepower. Power Factor issues generally are not hugely important for such a tiny system as long as you have it over-engineered - which is the norm. Efficiency (in terms of power factor) can certainly be improved for any of your individual loads however - if that is the key issue for you, then those would each require individual treatment regardless of your generator ratings. Not wise to spend a dollar to save a dime...  :o

dieselgman
« Last Edit: September 18, 2012, 12:05:42 PM by dieselgman »
ALL Things Lister/Petter - Americas
Lyons Kansas warehousing and rebuild operations

Quinnf

  • Rest in peace
  • Hero Member
  • *****
  • Posts: 645
    • View Profile
Re: Power factor - getting full power from a generator and maximizing efficiency
« Reply #35 on: September 19, 2012, 04:29:21 AM »
[snip].

wait for Bill's book

[snip]

What Bob said.  Bill's probably forgotten more over the years than most of us will ever know about the subject.   And Bob will agree with me that Mr. Bill is a fair dinkum frood who really knows where his towel is at.  The squirrels in his back yard don't think much of him, though.  But that's another story.

Quinn
« Last Edit: September 19, 2012, 04:33:40 AM by Quinnf »
Ashwamegh 6/1, PowerSolutions 6/1 "Kit" engine, and a Changfa R175a that looks like a Yanmar I once knew