Puppeteer

Author Topic: What size gen head  (Read 7131 times)

Ghoul

  • Newbie
  • *
  • Posts: 6
    • View Profile
What size gen head
« on: December 04, 2011, 06:21:54 PM »
Hi,
   
     Thanks again for all your help. I bought that metro6/1 with the old fairbanks generator head on a cart at that
Auction in NY.   He had it set up to be driven by an old laced flat belt and he must have never run it because the rotation of the generator
Would be wrong and the belt was way to long.   So, I am going to start from scratch.
I was looking for any ideas on generator head make and size and drive options.  Any help would be greatly appreciated

Regards,

Joe

dieselgman

  • Hero Member
  • *****
  • Posts: 3189
    • View Profile
    • Lister Parts
Re: What size gen head
« Reply #1 on: December 04, 2011, 06:56:04 PM »
By the numbers, 6 horsepower should yield 4.5kW. With drive losses and inefficiencies that degrades to about 3kW. We generally oversize our heads quite a bit for safety margins, and no real penalty for overcapacity. A 5kW or even 7.5kW head would operate fine with your 6/1. I'm sure you know about the ST Chinese heads that are in common circulation. They are generally a good bargain as long as you can tolerate the routine maintenance required on a brush type head.

dieselgman
« Last Edit: December 29, 2011, 04:23:23 AM by dieselgman »
ALL Things Lister/Petter - Americas
Lyons Kansas warehousing and rebuild operations

Ghoul

  • Newbie
  • *
  • Posts: 6
    • View Profile
Re: What size gen head
« Reply #2 on: December 04, 2011, 07:06:39 PM »
I was actually leaning toward the ST-5kW head but I figure I would ask.
Now I just have to find the right sheave and belt.  Is there a supplier you trust or just look on eBay?
Thanks again

dieselgman

  • Hero Member
  • *****
  • Posts: 3189
    • View Profile
    • Lister Parts
Re: What size gen head
« Reply #3 on: December 04, 2011, 10:14:35 PM »
We trust Tom Osborne at Central Georgia Gen.. If you need one in the midwest, we stock his same product in Kansas.

gary@dieselgen.com

dieselgman
ALL Things Lister/Petter - Americas
Lyons Kansas warehousing and rebuild operations

mike90045

  • Mendocino Metro
  • Hero Member
  • *****
  • Posts: 1594
  • Mmmm BBQ
    • View Profile
    • Mikes Solar PV page
Re: What size gen head
« Reply #4 on: December 04, 2011, 11:02:18 PM »
...because the rotation of the generator Would be wrong ....

Is there a directional arrow or something on the generator ?  Just wondering how it would be "wrong".  Most of the fan "blades" even seem just flat, no preference to direction.

dieselgman

  • Hero Member
  • *****
  • Posts: 3189
    • View Profile
    • Lister Parts
Re: What size gen head
« Reply #5 on: December 05, 2011, 01:15:17 AM »
Some versions of the ST may have brush alignment issues with reversing rotation but the head should work either way, with proper brush holder adjustments.

Dieselgman
ALL Things Lister/Petter - Americas
Lyons Kansas warehousing and rebuild operations

38ac

  • Hero Member
  • *****
  • Posts: 2324
    • View Profile
Re: What size gen head
« Reply #6 on: December 05, 2011, 01:52:59 AM »
I'm with Gary as for oversizing the heads. Given we have some rotating mass when running a head with a 6/1 you can use that mass to start elctric motor loads with a 5KW head that you might not start with a 3KW. The price penalty for going 5KW instead of 3 is very small.
Collector and horder of about anything diesel

ronmar

  • Hero Member
  • *****
  • Posts: 1227
    • View Profile
Re: What size gen head
« Reply #7 on: December 05, 2011, 02:49:40 AM »
The ST-5 is a great match for the 6/1.  As mentioned, the large spinning mass allows it to start fairly large induction motors way better than a  typical 3KW could(if at all:)).   All the ST's I have seen have had straight fin impellars and brush holders centered perpendicular to the shaft centerline.  They don't care which way they get spun...  For this ammount of power transfer I think you could go a long way before you would beat the serpentine microgroove belt.  I don't know if George over at utterpower is still selling the machined Allmand drive pullies, but I could not be happier with mine.  It is 8.25" in diameter machined to take up to an 8rib belt, and uses a tapered clamping bushing and key.  Installs onto a ST-5 shaft in about 2 minutes.  The belt runs from this pully around the 24" flywheel.  This ratio gives you 1800 generator RPM from I believe 630 engine RPM...
PS 6/1 - ST-5.

Horsepoor

  • Sr. Member
  • ****
  • Posts: 250
  • West Palm Beach, Florida
    • View Profile
Re: What size gen head
« Reply #8 on: December 05, 2011, 04:53:06 AM »
When I was picking up my ST generator head from Tom Osborn (Central Georgia Generator) I saw a ST 7.5 for something like $30 more than the ST 5. Since they both have the same shaft with the only real difference being more copper windings, I got the ST 7.5 for my 6/1 running at 800 rpm. I can get 4,400 watts sustained at 800 rpm. I have a very heavy two step pulley on the ST head allowing me to run the 6/1 at 600 rpm or 800 rpm depending upon needs. If I ever want to move the ST 7.5 to another, perhaps bigger, prime mover, I own a bigger generator head already. This setup can start very large loads using the larger ST head, and lots of spinning cast iron (I.e. 90 lbs on the ST spinning at 1800 rpm + the 6/1 cast iron flywheels at either 800 or 600 rpm). My emergency power needs in south florida are associated with August and September hurricanes. 100+ degree F daytime temperatures are common with high humidity after a hurricane. I figured the bigger generator head would run cooler and better at around 50% load, plus allow bigger loads to start.   
GTC 20/2 down rated to 850 rpm - ST 15
Metro 6/1 800 rpm on cart - ST 7.5

Jetpilot

  • Full Member
  • ***
  • Posts: 121
    • View Profile
Re: What size gen head
« Reply #9 on: January 07, 2012, 08:38:26 PM »
The ST-5 is a great match for the 6/1.  As mentioned, the large spinning mass allows it to start fairly large induction motors way better than a  typical 3KW could(if at all:)).   All the ST's I have seen have had straight fin impellars and brush holders centered perpendicular to the shaft centerline.  They don't care which way they get spun...  For this ammount of power transfer I think you could go a long way before you would beat the serpentine microgroove belt.  I don't know if George over at utterpower is still selling the machined Allmand drive pullies, but I could not be happier with mine.  It is 8.25" in diameter machined to take up to an 8rib belt, and uses a tapered clamping bushing and key.  Installs onto a ST-5 shaft in about 2 minutes.  The belt runs from this pully around the 24" flywheel.  This ratio gives you 1800 generator RPM from I believe 630 engine RPM...

I got my pully from George middle of last year. 

Derek