Author Topic: Any Indian rotating field ST alternators out here?  (Read 5377 times)

nikos

  • Newbie
  • *
  • Posts: 7
    • View Profile
Any Indian rotating field ST alternators out here?
« on: January 07, 2008, 01:16:57 PM »
Hello from Greece,

Been ages since I've posted anything.
A friend is in India so he'll arrange getting me a Powerline 6/1 from Mr. Patel from Anand corp.

While there I figure he might as well send me an alternator head. Anand make/sell stationary field, U-frame alternators, with separate
transfromer/choke rectifier for excitation.  I've only heard positive stuff about Mr. Patel for years now, so I'd prefer to get the head from him also.

Unlike the ST series though, power is taken off the brushes, which implies, to me at least, possible, substantial brush wear/replacement. Also, a 5kva head is quite pricey, at over $600

Can anyone comment on design as well as practical differences of these heads wrt the ST heads, as it seems it's getting away from the simplicity of the harmonic excitation of the ST heads.

Are there any "reputable" suppliers in India for ST heads or are they all stationary field types?

Any recommendations

regards,

nikos

biobill

  • Sr. Member
  • ****
  • Posts: 408
  • 'riods make good houseguests if fed right
    • View Profile
Re: Any Indian rotating field ST alternators out here?
« Reply #1 on: January 07, 2008, 02:29:58 PM »
Nikos,
  I run two of the stationary field type heads, a 3kw and a 4kw, and have had good results so far. Not running 24/7 but I do rack up the hours. Never replaced any brushes or other components though I did have to remount a field resistor.

  I'm not an expert but here's my understanding of how they differ from the ST types. (corrections welcome) They have 3 field windings
  One is energized initially by residual magnetism and the other two, each by rectified output from a 110v leg. As the output goes up, so does the power to the field. I think this keeps the voltage more stable from low load to high load than in the ST types. There are no electronics spinning on the shaft as with an AVR head. Disadvantages are that the brushes are carrying full output current (but they're pretty beefy and simple to replace) and you can't configure for full rated output at 110v (probably not an issue in Greece)

 The 4kw seems like the ideal size for a 6/1 and is built like a tank.      Bill
Off grid since 1990
6/1 Metro DI living in basement, cogen
6/1 Metro IDI running barn & biodiesel processer
VW 1.6 diesels all over the place
Isuzu Boxtruck, Ford Backhoe, all running on biodiesel
Needs diesel lawnmower & chainsaw

Doug

  • Hero Member
  • *****
  • Posts: 3386
  • Why don't pictures ever work for me?
    • View Profile
    • Doug's Petteroid Stuff
Re: Any Indian rotating field ST alternators out here?
« Reply #2 on: January 07, 2008, 08:41:38 PM »
Yes there is an Indian copy of what I am told is a erouteck...

I know nothing about the clone and have never seen what it was cloned from

http://www.topland-india.com/acalter.htm
It's a Good Life, If You Don't Weaken

Stan

  • Guest
Re: Any Indian rotating field ST alternators out here?
« Reply #3 on: January 07, 2008, 09:07:43 PM »
Isn't the Euro....whatever it's called... the gen head that Troy sells?
Stan

Doug

  • Hero Member
  • *****
  • Posts: 3386
  • Why don't pictures ever work for me?
    • View Profile
    • Doug's Petteroid Stuff
Re: Any Indian rotating field ST alternators out here?
« Reply #4 on: January 07, 2008, 09:09:06 PM »
Yes
It's a Good Life, If You Don't Weaken

rcavictim

  • Certified Generator Head and Grand Master Sparky
  • Hero Member
  • *****
  • Posts: 1827
    • View Profile
Re: Any Indian rotating field ST alternators out here?
« Reply #5 on: January 07, 2008, 09:58:06 PM »
The alternator head that came from England attached to my Petter Engine matches the unit seen in high power Lister SOM`s.  I have had it making 6 kW at 110 VAC. 60 Hz.  That`s 55 amps.  It uses four slip rings and eight bruishes arranged in parallel with four brushes and two rings on each side of the two wire single phase 110 volt output.  I had a lot of trouble and brush sparking, taking out the brushes when I first restored the set.  It has settled down now but the outermost ring closest the rear bearing has noticeably smaller worn diameter than the others.

The 12 -15 kW (not sure) alternator on my VW plant outputs 465 volts from the three armature slip rings.  Each ring speaks through two carbon brushes on a spring loaded brush fork.  I have not had any flashovers between rings but the phenolic insulation between two phases has evidence of a carbon track being carved out and filled with epoxy.  The brush gear has not given me any trouble and is not appearing to gobble brushes.

I read in a motor book that this is a ancient design and was not used in alternators larger than 15 kVA.
-DIY 1.5L NA VW diesel genset - 9 kW 3-phase. Co-gen, dualĀ  fuel
- 1966, Petter PJ-1, 5 kW air cooled diesel standby lighting plant
-DIY JD175A, minimum fuel research genset.
-Changfa 1115
-6 HP Launtop air cooled diesel
-Want Lister 6/1
-Large DIY VAWT nearing completion

M61hops

  • Sr. Member
  • ****
  • Posts: 299
    • View Profile
Re: Any Indian rotating field ST alternators out here?
« Reply #6 on: January 28, 2008, 06:35:05 AM »
Hi Nikos, I had an indian made 7.5KW head that worked very well even though it was wired like you describe.  The field was in series with the rotor and all the output current ran through the brushes as well as the diodes.  The more load I put on the generator the higher the output voltage went.  This worked well for starting motors.  If the 120V legs were more out of balance than 3 or 4 hundred watts the lights flickered though.  I got rid of the unit in favor of a ST rotating field head just because I thought the ST design would last longer.  I was not sure what would happen to the output of the indian style head if one of the diodes shorted or opened; that seemed like the weakest link of that design as all the load current went through each of the diodes.  I gave the indian genhead a good hard test and it worked well for the short time I had it, I just prefer the design of the ST head.  That's my opinion for what it's worth.   Leland
I pray everyday giving thanks that I have one of the "fun" mental disorders!