electricpete
Electrical
- May 4, 2001
- 16,774
I see across a wide range of literature that motor transient simulations are performed under the assumption that (as long as the supply voltage is balanced), the machine neutral voltage is equal to the supply system neutral voltage. Specifically the balanced phase-to-neutral voltages of the supply (Van, Vbn, Vcn) are assumed to appear individually across each leg of the wye connected machine winding. But I don’t see any discussion of the basis for the assumption (Krause’s book uses the assumption throughout without ever once addressing the basis for the assumption).
Under sinusoidal steady state conditions, we can easily verify the assumption is correct by impedance analysis.
But under transient conditions, we have a non-linear system (torque is the product of multiple state variables). No such linear impedance analysis is possible. What form of proof or verification is available for that assumption that the machine neutral voltage remains equal to supply system neutral voltage. What are the prerequisite conditions necessary to assure this assumption is satisfied?
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Under sinusoidal steady state conditions, we can easily verify the assumption is correct by impedance analysis.
But under transient conditions, we have a non-linear system (torque is the product of multiple state variables). No such linear impedance analysis is possible. What form of proof or verification is available for that assumption that the machine neutral voltage remains equal to supply system neutral voltage. What are the prerequisite conditions necessary to assure this assumption is satisfied?
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Eng-tips forums: The best place on the web for engineering discussions.