Bob
Lv 7
Bob asked in Science & MathematicsEngineering · 1 decade ago

If I connect an ACgenerator in parallel to the AC supply, how can I tell which way the current is flowing,?

I know an ammeter will show current, but on AC it won't show current direction. I need to know when the generator is drawing on the supply so it can be disconnected. I need to know when the generator is feeding the supply so it can be kept connected. It is a privately owned supply from another generator.

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  • 1 decade ago
    Favorite Answer

    well first thing u need to know is AC dosnt have direction, the AC flows forward and backward like a sine wave

    to connect ac in parallel u need to make sure that both of the generator are in phase otherwise the generator will cancel each other

    sence u need to get only the one side of the sine wave " which is only current going to one side and disconnect ont eh other" then that is called a half wave rectifier, its realy simple to make all u need to do is connecet a diode in searies with the genrator and this will block the drawing crrent as u mentioned it

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  • 1 decade ago

    You would use a contactor to sense the primary voltage. If the circuit is single phase, your contactor would need two N.O. and two N.C. Make-After-Break contacts.

    When the primary voltage is present it energizes the coil of the contactor. Normally Closed contacts will open disconnecting the load from the generator. Normally Open contacts will close connecting the load to the primary.

    When the primary voltage is not present the coil of the contactor will be deenergized. Normally Open contacts will open disconnecting the load from the primary. Normally Closed contacts will close connecting the load to the generator.

    Note: There would be other components necessary to make this circuit safe (over-current protection for example). Make sure that you know what you are doing, or you could damage your generators or start a fire.

    You can buy a device called a Transfer Switch to do this.

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  • TAREQ
    Lv 4
    1 decade ago

    First of all you need to understand that when connecting two deferent power supplies you need to do that with a process called synchronization.

    Second thing is that alternating current (AC) the movement or flow of electric charge reverses direction.

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  • NJGuy
    Lv 5
    1 decade ago

    You need an instrument called a synchroscope to be sure the paralleled generators are in synchronous operation. Otherwise, you could damage both generators.

    Source(s): 35 years experience in a generating station with multiple generators in parallel operation.
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  • 1 decade ago

    it you do that, you will blow something up, and maybe cause a fire.

    You cannot connect two AC sources in parallel, unless they are at the same voltage, and frequency and exactly in phase.

    .

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