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Active Contributor

Join Date: Mar 2011
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Converting Three Phase Motor to a Generator

03/13/2011 6:19 PM

I neede to know how to converting a tree phase motor to a electric generatar

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#1

Re: converting tree phase motor to a generata

03/13/2011 6:30 PM

How will you drive the generator, once it's converted? With another electric motor?

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#2
In reply to #1

Re: converting tree phase motor to a generata

03/13/2011 6:53 PM

using the energy generatede by the water comming from a dam 40 meters high.

I used a water pump and achieved rotation of the motor but no elecricity.

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#3
In reply to #2

Re: converting tree phase motor to a generata

03/13/2011 6:56 PM

OK,

Sorry. You'll need to furnish more information about the motor.

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#4
In reply to #3

Re: converting tree phase motor to a generata

03/13/2011 7:05 PM

Thnk for your colaboration

What kind of information you need?

My question is : if the motor is runnig is it necessary any modification with the wires?

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#5
In reply to #4

Re: converting tree phase motor to a generata

03/13/2011 7:22 PM
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#6

Re: Converting Three Phase Motor to a Generator

03/13/2011 8:59 PM

First off you need to understand the two types of "generators" (with AC, it's actually called an Alternator, generator refers to DC, but for simplicity lets just go with it for now). The two basic types are On-Line and Island. An Island generator stands alone, generating power for a small local distribution system, such as your house, with no other available power source. An ON-Line generator is connected to the normal utility power and ADDS available energy to the grid, but cannot function stand-alone.

An induction motor can only be used as an On-Line generator, it cannot be used as an Island generator without significant physical modification, at which point it no longer functions as an induction motor, and so becomes a Permanent Magnet Alternator. This is because in order for an induction motor to act as an induction generator, you nee two things; 1) and overhauling load, meaning a mechanical force that is spinning the motor shaft FASTER than it would spin as a motor, and 2) excitation of the windings, i.e. electrical energy to establish a magnetic field. For a pure induction motor then, that excitation energy must come from the grid (utility) power source. Without it, the spinning induction motor is just a dead weight.

So before going any further with this idea, describe how you intend to use it. If your intent was to capture energy from a water source and to be off the grid, you will need a Synchronous Alternator (or DC generator), not an induction motor/generator.

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#7
In reply to #6

Re: Converting Three Phase Motor to a Generator

03/14/2011 5:29 AM

Thank for your help I have a turbina that moves by the water AND moves the tree phases motor But when i measure on the wires comming from the motor no electricity Is produce Why no electricity???

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#8
In reply to #7

Re: Converting Three Phase Motor to a Generator

03/14/2011 9:14 AM

"But when i measure on the wires comming from the motor no electricity Is produce Why no electricity???"

Um, read point #2 in paragraph 2 of my response again. If you are not connected to another EXISTING power source, it will not work. If you want it to work without being connected to the grid, you cannot use an induction motor. You need to change one thing or the other.

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#9
In reply to #7

Re: Converting Three Phase Motor to a Generator

03/14/2011 8:28 PM

If its an induction motor you need to rotate it above synchronous speed. Hit

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#10
In reply to #7

Re: Converting Three Phase Motor to a Generator

03/15/2011 9:57 AM

How is a magnetic field to be provided inside the machine?

  • If the machine were to be a fixed magnet alternator, electricity would be produced. If the magnetic field were to be provided otherwise, then an additional source of electric power is needed in order to generate the magnetic field.
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