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Re: [microhydro] Re: need help in the C-2C connection of induction motor as generator.

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  • Tony Goffe
    ... From: Nando Sent: Tuesday, September 29, 2009 5:47 PM To: microhydro@yahoogroups.com Subject: Re: [microhydro] Re: need help in the
    Message 1 of 11 , Sep 30 10:45 AM
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      ...Nando,... I'm not trying to... "anything'.. (actually, you paid me a compliment, of sorts) As I am not a genius at hydro, I have had to rely on books for backup... Dr. Smith said rotation makes a diff... U say it does'nt .. the SKAT manual is full of Maths that I did'nt even TAKE in high school... ME?? I'm just trying to find funding (just got turned down again) to put in the MOST MINISCULE of hyrdros, so Jamaicans may see that this tech REALLY WORKS... I've been at this since 1993, When (if) I get to the stage and size of Hydro-plant that demands induction-type generators, THEN,...... the ROTATION RELEVANCE will become an ESSENTIAL piece of of my TECH VOCAB.. till then, I enjoy the back and forth banter the forum,..Loved Mr. St. Onge's video.. will agree that the end of the draft tube LOOKS kinda CLOSE to the outlet pool floor.. BUT he helped me a lot with this last proj, and find his equipment and approach, comfortable..(?????) Let me say, that you are obviously someone with a good heart and intentions, and what help you give positively affects lives world-wide.. I'm a minnow behind your dam... See, I am originally a Lapidarist, having discovered agates in my part of the island, and got into HYDRO as a means to produce a Cheaper Finished Product, than with the 80% (imported) oil-fired kilowatts our country now consumes. I am going back to stone-cutting with some knowledge of Hydro, and a LOT OF KNOWLEDGE ABOUT GOVERNMENT INCOMPETENCE, INNOVATIVE ILLITERACY, and of AID-AGENCIES UNBENDING RULES and general BLAH BLAH BLAH! (In my country, 60-80% of the money received by these agencies forin-country AID, is spent on office overheads and slaries for non-involved individuals (bureaucrats)... There is one agency, that in over 19 years of operation, HAS NEVER GRANTED MONEY FOR A RENEWABLE ENERGY PROJECT ! (sorry, ONCE, it did.... mine in 1995, the community, though. thought it was a cash hand-out thing, and it failed) Right now, I'm selling off all the Hydro paraphernalia of the years..... wish me good (better) fortune.. take care, tony

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

      From: "Nando" <nando37@...>
      Sent: Tuesday, September 29, 2009 5:47 PM
      To: microhydro@yahoogroups.com
      Subject: Re: [microhydro] Re: need help in the C-2C connection of induction motor as generator.



      Tony:

      Your message is kind of enigmatic, specially when you are placing it on top of my message which tends to be directed to me, is this the case ?.

      If this is the case, can you detail the reasoning, like to point out any part or point I may be in error or what are you trying to imply ?.

      Nando

      ----- Original Message -----
      From: Tony Goffe
      To: microhydro@yahoogroups.com
      Sent: Sunday, September 27, 2009 7:15 PM
      Subject: Re: [microhydro] Re: need help in the C-2C connection of induction motor as generator.

      ...MORE C2C... Let's see, .......... DR. Ngel Smith in his 1995 book "Motors as Generators for Microhydropower", published in concert with ITDG, states.... (1.) the motor must be Delta connected... (2) In using the C2C connection, it is essential to ensure that the DIRECTION OF ROTATION (my emphasis), of the rotor is correct. If the capacitors are arranged correctly, the 'C phase' will produce its peak voltage before the '2C phase'. If the opposite occurs, the generator will run inefficiently and overheat. In an un-labeled (just in case !!) motor, rotation may be checked by running the machine with both phase sequences. The correct rotation can be determined by measuring the power output or the winding currents (temperature?) AND...I don't even want to go into what the SKAT manual "Induction Motors as Generators" says about this ...... Keep it Simple as Craig at "catmilltech" says ....

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      From: "Nando" <nando37@...>
      Sent: Saturday, September 26, 2009 12:28 PM
      To: microhydro@yahoogroups.com
      Subject: Re: [microhydro] Re: need help in the C-2C connection of induction motor as generator.

      I failed to indicate that the "opposite polarity" connection was for a Delta connection -- and not for the STAR connection.

      Nando

      ----- Original Message -----
      From: Nando
      To: microhydro@yahoogroups.com
      Sent: Saturday, September 26, 2009 8:13 AM
      Subject: Re: [microhydro] Re: need help in the C-2C connection of induction motor as generator.

      Tony:

      Do you need a more or deeply defined explanation .

      Reconnectable windings in a motor should keep the polarity ( start - end ) to keep the produced voltage in phase within all the windings/

      If you place a winding in opposite polarity is like placing a battery bank with some batteries in reverse polarity, the voltage is reduced and the motor may dissipate excessive power.

      Rotation direction does not matter if the windings are kept in phase (between themselves) .

      Rotation change, in some motors, can be accomplished with phase change of two winding phases , if a 3 phase motor, for a single phase motor, the starting field coil is reconnected alternating the connection position of its terminals.

      It would take a long dissertation to explain the C & 2C technical reasonings.

      Ideally, the phase rotation direction should be kept , where the motor has A,B,C phases which will produce a rotation in the A ,B ,C direction and in this case, A with no Capacitor, B with C, and C with 2C capacitors.

      The Capacitors value can be calculated to a close value if the motor voltage, frequency, running current, and locked current are available.

      Also with the locked current one can calculate a capacitor ( as a motor ) to improve the Power Factor of the motor.

      Nando

      ----- Original Message -----
      From: Tony Goffe
      To: microhydro@yahoogroups.com
      Sent: Friday, September 25, 2009 3:29 AM
      Subject: re: [microhydro] Re: need help in the C-2C connection of induction motor as generator.

      ...This is the MOST succint (straightforward) explanation of the C2C connection I have ever seen! Thanks from all we stuggling non-techies.. One thing tho, ...does the ROTATION of the rotor make a difference..?? That is, does the C phase have to be contacted before the 2C...or vice versa ?????

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      From: "catmilltech" <craig@...>
      Sent: Thursday, September 24, 2009 5:43 PM
      To: microhydro@yahoogroups.com
      Subject: [microhydro] Re: need help in the C-2C connection of induction motor as generator.

      Hi
      Wire the motor in delta.
      Connect one 35uf capacitor across one of the windings.
      Connect one 70uf capacitor across another winding.
      The third winding has no capacitor.
      Take the single phase load across the 35uf capacitor.
      This is a C2C connection.
      Good luck
      Craig

      --- In microhydro@yahoogroups.com, isisdro marfori <ingko_yeah@...> wrote:
      >
      > My name is Ingko Marfori from the Philippines. I work as a faculty at De La Salle University in the mechanical engineering dept. I also volunteer in the micro hydro projects of my university. Currently, we are working on a small micro hydro project. Im using a 3 phase 3 HP induction motor as generator. I got it producing 220 volts at 60Hz when the motor is connected in Y while 35uF capacitors are connected in delta which resulted in a 3 phase line. I would like to get the motor producing single phase using the C-2C connection so that we can eliminate the need to balance the load on each line. As i understood, the C-2C connection requires the motor to be wired in delta which i did. I tried 20uF, 35uF, and 40uF, but it did not work. The motor is a dual voltage type that can accommodate 220 and 440 volts. Does this have an effect on the C-2C connection? We will be installing the micro hydro this September 27 and advise would be
      > greatly appreciated.
      > Ingko
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