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Synchronus Machine Characteristics (AFNL & AFSC)

  1. Oct 13, 2014 #1
    Hi everyone,
    I'm a little confused what is going on in our text book. There are a number of questions that state the table below has the Open Circuit (No Load) and Short Circuit Characteristics of some synchronous machine.
    But then the columns don't seem to match that wording (I'd think that open circuit would be first)

    I'm wondering if someone can confirm this thought process is right.

    If you are looking at a GENERATOR the short circuit filed current (AFSC) will be larger than the no load field current (AFNL) resulting in a short circuit ratio (SCR) less than 1

    If you are looking at a MOTOR the AFSC will be SMALLER than the AFNL resulting in a SCR greater than 1?

    Does this seem correct?? Or am I way off base here??
  2. jcsd
  3. Oct 13, 2014 #2
    No, it isn't correct. Short circuit currents are larger than no load currents for motors too
  4. Oct 13, 2014 #3
    So then you can never have an SCR > 1?

    This text book is borked it has a couple examples where they calculate the SCR to be > 1
  5. Oct 13, 2014 #4
    Sync generator and sync motor are in principle same things. Only the direction of the flow of energy is reversed. Therefore, I don't know what they are talking about (or I misinterpreted )
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