You are an electrician working in an industrial plant. A 30-hp three-phase induction motor has a current draw of 36 amperes at full load. The motor is connected to a 480-volt line. A three-phase wattmeter indicates a true power of 22 kW. Determine the power factor of the motor and the amount of capacitance needed to correct the power factor to 95%. Also determine the minimum voltage rating of the capacitors. The capacitors are to be connected in wye.

You are an electrician working in an industrial plant. A 30-hp three-phase induction motor has a current draw of 36 amperes at full load. The motor is connected to a 480-volt line. A three-phase wattmeter indicates a true power of 22 kW. Determine the power factor of the motor and the amount of capacitance needed to correct the power factor to 95%. Also determine the minimum voltage rating of the capacitors. The capacitors are to be connected in wye.

Delmar's Standard Textbook Of Electricity

7th Edition

ISBN:9781337900348

Author:Stephen L. Herman

Publisher:Stephen L. Herman

Chapter26: Three-phase Circuits

Section: Chapter Questions

Problem 3PA: You are an electrician working in an industrial plant. A 30-hp three-phase induction motor has a...

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You are an electrician working in an industrial plant. A 30-hp three-phase induction motor has a current draw of 36 amperes at full load. The motor is connected to a 480-volt line. A three-phase wattmeter indicates a true power of 22 kW. Determine the power factor of the motor and the amount of capacitance needed to correct the power factor to 95. Also determine the minimum voltage rating of the capacitors. The capacitors are to be connected in wye.
An industrial plant consisting primarily of induction motor loads absorbs 500 kW at 0.6 power factor lagging. (a) Compute the required kVA rating of a shunt capacitor to improve the power factor to 0.9 lagging. (b) Calculate the resulting power factor if a synchronous motor rated at 500 hp with 90 efficiency operating at rated load and at unity power factor is added to the plant instead of the capacitor. Assume constant voltage (1hp=0.746kW).
A single-phase motor takes 10A at a power factor of 0.7 lagging when connected to a 230V, 50 Hz supply. A capacitor bank is connected in parallel with the motor to raise the power factor to unity.i) Draw the phasor diagram before and after power factor correction with the supply voltage taken as the reference phasor. ii) Calculate the percentage change in the supply current after power factor correction.iii) Calculate the value of capacitance required.
A 500-V, 50-Hz single-phase motor takes a full load current of 50 A at a pf of 0.959 lagging. What capacitance must be placed in parallel with the motor to raise the pf to unity?
Question 1. An industrial load consisting of a set of induction motors connected to a 220 V, 60 Hz single phase source consumes 50 kW with a back power factor of 0.8. The power factor will be increased back to 0.95 by connecting a set of capacitors in parallel. For this, calculate the VA value that the connected capacitor will provide.
A single-phase motor draws 180 W at a power factor of 0.8 lagging when connected across a 240 Vrms, 60-Hz source. A capacitor is connected in parallel with the load to produce a unity power factor. Determine the required capacitance. The required capacitance = ____ μF.
The current in a pure capacitor circuit is i=0.17cos500t. If the rms value of the impressed emf is 80 volts. a) What are the equation for the voltage and power? b) What is the circuit frequency?
An impedance coil having a resistance of 15 ohms and an inductance of 0.08 henryis connected in series with a variable capacitor. If a 117 volt 60 cps source isconnected to the circuit, what will be the capacitance of the capacitor and the current(a) when the circuit has a power factor of 0.866 leading and (b) when the voltagedrop across the coil is equal to the voltage drop across the capacitor?
A 150 – microfarad capacitor is connected to a 220 – volt, 60 – cycle source. Calculate (a) the capacitive reactance, (b) the current in the circuit, (c) the average power taken by the capacitor, and (d) the maximum power delivered to the capacitor. DRAW THE PHASOR DIAGRAM IF POSSIBLE. ROUND OFF TO FOUR DECIMAL PLACES
A 400-V, 3-phase induction motor load takes 900 kVA at a power factor of 0.707. Calculate the KVA rating of the capacitor bank to raise the resultant power factor of the installation of 0.866 lagging. Find also the resultant power factor when the capacitors are in circuit and the motor load has fallen to 300 kVA at 0.5 power factor.
A 240 rms 60 Hz source supplies a parallel combination of a 4.5-kW heater and a 27-kVA inductor motor whose power factor is 0.82. Determine the kVA rating of the capacitor required to adjust the system power factor to 0.9 lagging and the value of the capacitor required?
A series circuit consisting of a resistor that dissipates 640watts, a coil and an ideal capacitor is connected across a 220volts, 60Hz power supply. The current drawn by the load is 8 amperes. The voltage across the coil is 150 volts and its power factor is 0.8 lagging. Determine: a. the resistance of the resistor (10 Ohms)b. the resistance and the inductance of the coil ( 15 Ohms, 29.8416 mH)c. the voltage across the capacitor (181.6515 V)d. the capacitance of the capacitor (116.8207 μF)