5-4. Assume that the field current of the generator in Problem 5-2 is adjusted to achieve rated voltage (2300 V) at full load conditions in each of the questions below. (a) What is the efficiency of the generator at rated load? (b) What is the voltage regulation of the generator if it is loaded to rated kilovoltamperes with 0.8-PF- lagging loads? (c) What is the voltage regulation of the generator if it is loaded to rated kilovoltamperes with 0.8-PF- leading loads? (d) What is the voltage regulation of the generator if it is loaded to rated kilovoltamperes with unity-power- factor loadde?

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Please answer Question 5-4 ONLY!

**Problem 5-4: Analysis of Generator Performance at Rated Conditions**

Assume that the field current of the generator mentioned in Problem 5-2 is adjusted to maintain a rated voltage of 2300 V under full load conditions. Analyze the performance of this generator by addressing the following questions:

**(a)** What is the efficiency of the generator at rated load?

**(b)** Determine the voltage regulation of the generator when it is loaded to rated kilovolt-amperes (kVA) with a power factor of 0.8 lagging.

**(c)** Determine the voltage regulation of the generator when it is loaded to rated kilovolt-amperes (kVA) with a power factor of 0.8 leading.

**(d)** Determine the voltage regulation of the generator when it is loaded to rated kilovolt-amperes (kVA) with a unity power factor.

---

No graphs or diagrams are included with this question set.
Transcribed Image Text:**Problem 5-4: Analysis of Generator Performance at Rated Conditions** Assume that the field current of the generator mentioned in Problem 5-2 is adjusted to maintain a rated voltage of 2300 V under full load conditions. Analyze the performance of this generator by addressing the following questions: **(a)** What is the efficiency of the generator at rated load? **(b)** Determine the voltage regulation of the generator when it is loaded to rated kilovolt-amperes (kVA) with a power factor of 0.8 lagging. **(c)** Determine the voltage regulation of the generator when it is loaded to rated kilovolt-amperes (kVA) with a power factor of 0.8 leading. **(d)** Determine the voltage regulation of the generator when it is loaded to rated kilovolt-amperes (kVA) with a unity power factor. --- No graphs or diagrams are included with this question set.
**5-2.**
A 2300-V 1000-kVA 0.8-PF-lagging 60-Hz two-pole Y-connected synchronous generator has a synchronous reactance of 1.1 Ω and an armature resistance of 0.15 Ω. At 60 Hz, its friction and windage losses are 24 kW, and its core losses are 18 kW. The field circuit has a dc voltage of 200 V, and the maximum \( I_f \) is 10 A. The resistance of the field circuit is adjustable over the range from 20 to 200 Ω. The OCC of this generator is shown in Figure P5-1.

(a) How much field current is required to make \( V_T \) equal to 2300 V when the generator is running at no load?

(b) What is the internal generated voltage of this machine at rated conditions?

(c) How much field current is required to make \( V_T \) equal to 2300 V when the generator is running at rated conditions?

(d) How much power and torque must the generator’s prime mover be capable of supplying?

**Graph Description:**
The graph provided is labeled, "Open-circuit terminal voltage, V" on the vertical axis and "Field current, A" on the horizontal axis. The voltage ranges from 0 to 3000 V and the current ranges from 0 to 10 A.

- At approximately 0 A, the voltage is approximately 0 V.
- As the field current increases, the open-circuit terminal voltage increases non-linearly, forming a curve that gradually flattens out as it approaches 10 A.
- The curve starts steeply, indicating that small increases in field current result in relatively large increases in voltage at low currents.
- As the field current reaches higher values, the increase in voltage per increase in current diminishes. 

This curve is typical for an open-circuit characteristic (OCC) of a synchronous generator, demonstrating the relationship between the field current and the open-circuit generated voltage.
Transcribed Image Text:**5-2.** A 2300-V 1000-kVA 0.8-PF-lagging 60-Hz two-pole Y-connected synchronous generator has a synchronous reactance of 1.1 Ω and an armature resistance of 0.15 Ω. At 60 Hz, its friction and windage losses are 24 kW, and its core losses are 18 kW. The field circuit has a dc voltage of 200 V, and the maximum \( I_f \) is 10 A. The resistance of the field circuit is adjustable over the range from 20 to 200 Ω. The OCC of this generator is shown in Figure P5-1. (a) How much field current is required to make \( V_T \) equal to 2300 V when the generator is running at no load? (b) What is the internal generated voltage of this machine at rated conditions? (c) How much field current is required to make \( V_T \) equal to 2300 V when the generator is running at rated conditions? (d) How much power and torque must the generator’s prime mover be capable of supplying? **Graph Description:** The graph provided is labeled, "Open-circuit terminal voltage, V" on the vertical axis and "Field current, A" on the horizontal axis. The voltage ranges from 0 to 3000 V and the current ranges from 0 to 10 A. - At approximately 0 A, the voltage is approximately 0 V. - As the field current increases, the open-circuit terminal voltage increases non-linearly, forming a curve that gradually flattens out as it approaches 10 A. - The curve starts steeply, indicating that small increases in field current result in relatively large increases in voltage at low currents. - As the field current reaches higher values, the increase in voltage per increase in current diminishes. This curve is typical for an open-circuit characteristic (OCC) of a synchronous generator, demonstrating the relationship between the field current and the open-circuit generated voltage.
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