{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

12-Final Exam Practice Problems

# 12-Final Exam Practice Problems - ELECTRICAL ENGINEERING...

This preview shows pages 1–2. Sign up to view the full content.

ELECTRICAL ENGINEERING DEPARTMENT California Polytechnic State University EE255 Practice Problems `````````````````````````````````````````````````````````````````````````````````````````````````````````````````` ```` Problem #1 A 100-KVA, 11,000:2,200-V, 60-Hz, single-phase transformer gave the following test results Voltage current power Open-circuit test: 2200V 1.59 A 980 W Short-circuit test: 580V 9.1 A 1100 w a) Determine the parameters of the approximate equivalent circuit referred to low-voltage side. b) Determine the voltage regulation of the transformer when supplying rated load at 2200 V and 0.8 power factor leading. [VR=-2.1%] c) Determine the all-day efficiency of the transformer for the following load cycle: 8 hours at rated load and .8 pf lagging, 8 hours at 80% full-load and 0.8 pf lagging, and 8 hours at 50% full-load and 0.8 pf lagging. The load is connected to the low voltage side. [Efficiency=97.4%] Problem #2 A 15-hp, three-phase, 8-pole, 440-V, 60-Hz, wound-rotor induction motor has its stator and rotor windings connected in wye. The ratio of the effective stator turns to the effective rotor turns is 2:1. The mechanical losses (friction + windage) are 220 W at rated speed and may be assumed constant from no-load to full-load. The stator and

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### Page1 / 2

12-Final Exam Practice Problems - ELECTRICAL ENGINEERING...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online