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A 25 kVA, 400 V, D - connected, 3-phase, cylindrical rotor synchronous generator requires a field current of 5 A to maintain the rated armature current under short-circuit condition. For the same field current, the open-circuit voltage is 360 V. Neglecting the armature resistance and magnetic saturation, its voltage regulation (in % with respect to terminal voltage), when the generator delivers the rated load at 0.8 pf leading, at rated terminal voltage is _________.
    Correct answer is between '-15,-14'. Can you explain this answer?
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    A 25 kVA, 400 V, D - connected, 3-phase, cylindrical rotor synchronous...
    Hint: Obtained regulation should be negative.
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    A 25 kVA, 400 V, D - connected, 3-phase, cylindrical rotor synchronous...
    Given data:
    - Rated apparent power (S) = 25 kVA
    - Rated terminal voltage (Vt) = 400 V
    - Field current (If) at short-circuit condition = 5 A
    - Open-circuit voltage (Voc) at If = 5 A = 360 V
    - Power factor (pf) = 0.8 leading

    To find: Voltage regulation of the synchronous generator at rated load.

    1. Calculating the synchronous reactance (Xs):
    The synchronous reactance (Xs) can be calculated using the formula:
    Xs = Voc / If
    Substituting the given values, we get:
    Xs = 360 V / 5 A
    Xs = 72 Ω

    2. Calculating the synchronous impedance (Zs):
    The synchronous impedance (Zs) can be calculated using the formula:
    Zs = Vt / (S / √3)
    Substituting the given values, we get:
    Zs = 400 V / (25 kVA / √3)
    Zs = 400 V / (25 × 10^3 VA / √3)
    Zs = 400 V / (25 × 10^3 V / √3)
    Zs = 400 V / (25 × 10^3 V × √3)
    Zs = 0.032 Ω

    3. Calculating the synchronous reactance voltage drop (Vr):
    The synchronous reactance voltage drop (Vr) can be calculated using the formula:
    Vr = If × Xs
    Substituting the given values, we get:
    Vr = 5 A × 72 Ω
    Vr = 360 V

    4. Calculating the terminal voltage (Vt_actual):
    The actual terminal voltage (Vt_actual) can be calculated using the formula:
    Vt_actual = Vt - Vr
    Substituting the given values, we get:
    Vt_actual = 400 V - 360 V
    Vt_actual = 40 V

    5. Calculating the voltage regulation:
    The voltage regulation can be calculated using the formula:
    Voltage Regulation = (Vt - Vt_actual) / Vt × 100%
    Substituting the given values, we get:
    Voltage Regulation = (400 V - 40 V) / 400 V × 100%
    Voltage Regulation = 360 V / 400 V × 100%
    Voltage Regulation = 90%

    However, since the generator is delivering power at a leading power factor, the voltage regulation will be negative. Therefore, the correct answer is between -15% and -14%.
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    A 25 kVA, 400 V, D - connected, 3-phase, cylindrical rotor synchronous generator requires a field current of 5 A to maintain the rated armature current under short-circuit condition. For the same field current, the open-circuit voltage is 360 V. Neglecting the armature resistance and magnetic saturation, its voltage regulation (in % with respect to terminal voltage), when the generator delivers the rated load at 0.8 pf leading, at rated terminal voltage is _________.Correct answer is between '-15,-14'. Can you explain this answer?
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    A 25 kVA, 400 V, D - connected, 3-phase, cylindrical rotor synchronous generator requires a field current of 5 A to maintain the rated armature current under short-circuit condition. For the same field current, the open-circuit voltage is 360 V. Neglecting the armature resistance and magnetic saturation, its voltage regulation (in % with respect to terminal voltage), when the generator delivers the rated load at 0.8 pf leading, at rated terminal voltage is _________.Correct answer is between '-15,-14'. Can you explain this answer? for Electrical Engineering (EE) 2024 is part of Electrical Engineering (EE) preparation. The Question and answers have been prepared according to the Electrical Engineering (EE) exam syllabus. Information about A 25 kVA, 400 V, D - connected, 3-phase, cylindrical rotor synchronous generator requires a field current of 5 A to maintain the rated armature current under short-circuit condition. For the same field current, the open-circuit voltage is 360 V. Neglecting the armature resistance and magnetic saturation, its voltage regulation (in % with respect to terminal voltage), when the generator delivers the rated load at 0.8 pf leading, at rated terminal voltage is _________.Correct answer is between '-15,-14'. Can you explain this answer? covers all topics & solutions for Electrical Engineering (EE) 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for A 25 kVA, 400 V, D - connected, 3-phase, cylindrical rotor synchronous generator requires a field current of 5 A to maintain the rated armature current under short-circuit condition. For the same field current, the open-circuit voltage is 360 V. Neglecting the armature resistance and magnetic saturation, its voltage regulation (in % with respect to terminal voltage), when the generator delivers the rated load at 0.8 pf leading, at rated terminal voltage is _________.Correct answer is between '-15,-14'. Can you explain this answer?.
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