Question

A 230 V shunt direct-current machine on no-load has a speed of 900 rpm and a...

A 230 V shunt direct-current machine on no-load has a speed of 900 rpm and a supply current of 2.5 A. The machine parameters are:
• Field resistance: 230 Ω
• Armature resistance: 0.3 Ω
• Voltage drop/brush: 1.0 V (current independent)
a) Calculate the electromagnetic torque, speed, the output power and the overall efficiency when the supply current is 35 A, assuming that the friction and wind-age torque is constant. (16 points)
b) The machine operates now as generator and is driven to generate 35 A into the supply at 230 V and at 900 rpm. Determine the overall efficiency. (6 points)
c) Calculate the extra field resistance required to make to make the transition pos-sible from motor operation to generator operation. (3 points)

0 0
Add a comment Improve this question Transcribed image text
Know the answer?
Add Answer to:
A 230 V shunt direct-current machine on no-load has a speed of 900 rpm and a...
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Not the answer you're looking for? Ask your own homework help question. Our experts will answer your question WITHIN MINUTES for Free.
Similar Homework Help Questions
  • A 230 V shunt direct-current machine on no-load has a speed of 900 rpm and a supply current of 2.5 A. The machine parameters are: • Field resistance: 230 Ω • Armature resistance: 0.3 Ω • Voltage drop/...

    A 230 V shunt direct-current machine on no-load has a speed of 900 rpm and a supply current of 2.5 A. The machine parameters are: • Field resistance: 230 Ω • Armature resistance: 0.3 Ω • Voltage drop/brush: 1.0 V (current independent) a) Calculate the electromagnetic torque, speed, the output power and the overall efficiency when the supply current is 35 A, assuming that the friction and wind-age torque is constant. (16 points) b) The machine operates now as generator...

  • 1. A shunt machine, while running as a generator, has an induced voltage of 260 V...

    1. A shunt machine, while running as a generator, has an induced voltage of 260 V at 1200 rpm. Its armature and field resistances are 0.2 2 and 110 Q, respectively. If the machine is run as a shunt motor, it takes 4 A at 220 V (i) Draw the schematic diagram of the machine as a generator. (ii) Draw the schematic diagram of the machine as a motor (iii)At a certain load the motor takes 30 A at 220...

  • QUESTION 1 A) (10 marks) A 10 kW, 250 V DC self-excited shunt generator, with an...

    QUESTION 1 A) (10 marks) A 10 kW, 250 V DC self-excited shunt generator, with an armature resistance of 0.1 ohm, is delivering 80 % of rated power to the mains at rated voltage when being run at 1000 r.p.m. (revolutions per minute). The field circuit resistance is 220 ohms. The brush contact drop is 0.5 V and rotational (mechanical) losses are 750 W Calculate The induced voltage The electromagnetic torque developed The shaft torque The overall efficiency B) (15...

  • A) The input current to a 220 V, short-shunt compound motor at no load is 6 A. The shunt- field c...

    a) The input current to a 220 V, short-shunt compound motor at no load is 6 A. The shunt- field circuit resistance is 220 Ω; the armature resistance is 0.112, and the series-field resistance is 0.1 Ω, what is the stray power loss ? (b) Assume the input rating of the motor in Part (a) to be 66 A at 220 V with a no-load speed of 1000 rpm. If the stray power loss varies as the counter-electromotive force and...

  • A 30 hp, 240 V, 1150 rpm de shunt motor operating at rated conditions has an efficiency of 88.5%. The armature circuit resistance and field circuit resistance are 0.096 Ω and 936 Ω respectively. Calc...

    A 30 hp, 240 V, 1150 rpm de shunt motor operating at rated conditions has an efficiency of 88.5%. The armature circuit resistance and field circuit resistance are 0.096 Ω and 936 Ω respectively. Calculate the following: (a) the armature current; b) the output torque (c) the mechanical developed power (d) the mechanical developed torque; and, e) the external resistance required in series with the armature to limit the starting torque to 200 % of rated torque. If the load...

  • A DC shunt generator delivers a load current of 50 A at 300 V with its...

    A DC shunt generator delivers a load current of 50 A at 300 V with its field circuit resistance being 50 ohms. The armature circuit resistance of the generator is 2 ohms The generator has a linear excitation with a constant rotor speed. The brush voltage drop is negligible. Aiding with a drawing of equivalent circuit, estimate: i) The field current, armature current and generated voltage of the generator when it delivers the 100 A at 300V; and (ii) The...

  • A 250 V, 10 KW, 1200 rpm dc shunt motor has a full load efficiency of...

    A 250 V, 10 KW, 1200 rpm dc shunt motor has a full load efficiency of 80 percent. Its field and armature resistances are 110 ohms and .25 ohm respectively. Calculate the value of the resistance to be inserted in series with the armature and the power lost in the armature circuit to reduce the speed to 80 percent when the load torque is constant regardless of the speed.

  • 3. A 25-kW, 230-V shunt motor has an armature resistance of 0.064 Ω and a field-circuit...

    3. A 25-kW, 230-V shunt motor has an armature resistance of 0.064 Ω and a field-circuit resistance of 95 Ω. The motor delivers rated output power at rated voltage when its armature current is 122 A. When the motor is operating at rated voltage, the speed is observed to be 1150 r/min when the machine is loaded such that the armature current is 69.5 A a. Calculate the rated-load speed of this motor In order to protect both the motor...

  • A 6 hp, 180 V shunt dc motor draws a full-load current of 30 A from the power supply. The motor h...

    A 6 hp, 180 V shunt dc motor draws a full-load current of 30 A from the power supply. The motor has a field (shunt) resistance of 150 Ω. The armature resistance of the motor is 0.1 Ω. When the motor speed is 1800 rpm (this is not the full-load speed), the relationship between the induced voltage

  • Q1: (30 points) A shunt DC generator, running at a constant speed of 1400 rpm, has...

    Q1: (30 points) A shunt DC generator, running at a constant speed of 1400 rpm, has a field resistance of 200 22 and armature resistance of 0.5 12. Ignore armature reaction and assume a 400 W rotational loss. a) [15] While supplying no load, the induced armature voltage is 280 V. Calculate the input power. b) [15] When the generator is loaded, the developed power is found to be 4.1 kW at the same magnetic flux of the field found...

ADVERTISEMENT
Free Homework Help App
Download From Google Play
Scan Your Homework
to Get Instant Free Answers
Need Online Homework Help?
Ask a Question
Get Answers For Free
Most questions answered within 3 hours.
ADVERTISEMENT
Active Questions
ADVERTISEMENT