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Connection of two Generators

  1. Jul 20, 2012 #1
    Hi guys,

    If we connect 2 Dc generators in parallel. First generator ratings (200 V, 400 Amp),and the

    second Generator (400 V, 500 Amp). What are the output voltage and the max.output current?

    What if we connect them in Series ?

    What if these generators are Ac generators?
  2. jcsd
  3. Jul 20, 2012 #2


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    Staff: Mentor

    Welcome to the PF.

    What is the context of the question? Is this for schoolwork, or are you planning some sort of power system?

    You cannot connect voltage sources of different voltages in parallel (in general). Voltage sources want to hold their output voltage constant, so if you connect two different voltage sources in parallel, they will overcurrent trying to fight each other.

    If the voltages are similar, you can "diode OR" the two DC outputs, so that the slightly higher voltage power supply supplies the load current. This is commonly done in battery-backup situations, so the diode OR'ed battery can take over if the power supply fails.

    AC generators can be paralleled if their output voltages are the same, and if there is a mechanism to keep them synchronized. The Honda 2000W portable generators have this feature, for example.
  4. Jul 20, 2012 #3
    What you are asking is perfectly normal in power engineering although the disparity between generators you suggest is not.

    However your specifications are short of some additional parameters.

    The method of calculating the effect of parallel generators or batteries has been posted here several times.
  5. Jul 21, 2012 #4


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    Science Advisor
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    2017 Award

    This is very true but it needs to be pointed out that the control of the power input to parallel generators needs to be very precise and it's seriously not trivial to get optimum performance - it's actually quite hard not to have them jumping off their beds! (My old Dad's description of what could happen)
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