Home generator. What is acceptable power?

Discussion in 'General Electronics Chat' started by Namenotfound, Oct 18, 2014.

  1. Namenotfound

    Thread Starter New Member

    Oct 18, 2014
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    Alright so iv got an antique home generator (10kw 2phase 240vac. The frequency and voltage fluctuates from 62hz 240vac without a load to 57/58hz 220v under about a 70% load. What I would like to know is how severe are the effects of low frequency on eletronics. Also the feild Voltage is about 3vdc to 15vdc under these condishons. I'm also not compleatly sure what type of transformer is used to make the feild current but I can tell you that both phases of the primary side is in series with the output (dose that make sense?) and one side of the secondary is taped to one of the phases before passing through a rectofier. I'll try to post a picture of the schmatic that the best I can do to describe it. Anyway I was wondering what effects would the varying hz have on the output of the xfmr and ultimately the voltage output of the generator. Look on the far right side of the schmatic. Any help is appreciated. Thankyou
     
  2. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    Ok, you've told us what you don't know about electronics. What experiences do you have with electronics, physics and math (so we can start explaining from a point you can understand)?
     
  3. Namenotfound

    Thread Starter New Member

    Oct 18, 2014
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    Iv read thru dc and ac circuits and just started reading about semiconductors. Iv got a fair grasp of concepts however I lack practical experience. I'm not afraid of math but please tell me what the variables are referring to.
     
  4. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    57 to 62Hz is close enough...
     
  5. crutschow

    Expert

    Mar 14, 2008
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    As Mike stated, it's unlikely that a range of 57 to 62 Hz will have any affect on the devices connected to it. Many modern electronics are designed for 50-60Hz so they will work most places in the world (except perhaps if someone is still using the old 25Hz generators);).
     
  6. KeepItSimpleStupid

    Well-Known Member

    Mar 4, 2014
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    It might screw up the time on a clock based on a synchronous motor.
     
  7. studiot

    AAC Fanatic!

    Nov 9, 2007
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    As others have said, it sounds like the system is within normally acceptable limits. 240 to 220 volt drop at 7KVA is pretty reasonable.

    Also as KISS said I would not run old fashioned electric clocks from this.

    So all that remains if for the owner to keep the maintenance work up to date.
     
  8. Namenotfound

    Thread Starter New Member

    Oct 18, 2014
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    Than you that puts my mind at ease but what about that xfmr what type is it? Iv look all over the Internet iv found some close to it but never one with the secondary taped to the primary like that.
     
  9. Namenotfound

    Thread Starter New Member

    Oct 18, 2014
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    the reason I ask is because as I understand it hz is directly related to engine speed voltage is controlled by the curent in the feild windings. All the current passes through that transformer so the output from it is in proportion to the load. However if you manually change speed the engine voltage changes. So dose the frequency have an effect on the transformer? Best as i can tell it dose. (As I'm typing this now I'm wondering if it dose change while under load. I'll preform some experiments later today.) please bare with me I may have misspoke
     
  10. tcmtech

    Well-Known Member

    Nov 4, 2013
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    The transformer you are asking about is a sort of current to voltage converter that rasies the excitor voltage and power proportionally to the load being placed on the generator.

    Simple old fasioned self compensating voltage regulation is what its doing.

    BTW its not a two pahse genset its a single phase with a center tapped 240 VAC that gives you the two 120 volt lines with 240 VAC across them.

    As far as correct speed and voltage setup with those I typically shoot for 63 - 64 hz and 250 VAC noload and 56- 57 HZ 230 VAC at 100% rated capacity.

    There should be a set of adjustments on the engine governor for setting the speed and droop range which unfortunatley without a proper manual takes a bit of trial and error to get the droop adjustment set right.
     
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  11. Namenotfound

    Thread Starter New Member

    Oct 18, 2014
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    Thanks. Ya I guess if I'd of said single phase everyone would have known what I was saying. Forgive my ignorance I'm only beginning. Aside from this forum I don't have anyone to even discuss electrical concepts. I'm the smartest person I know which is kinda scary
     
  12. alfacliff

    Well-Known Member

    Dec 13, 2013
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    have you tried to lookup the mfgrs info on your generator? I have an old 3 kw, and a search brought me the adjustment instructions for the governor that holds the speed and frequency steady.
     
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