Electric Motor Control
10th Edition
ISBN: 9781133702818
Author: Herman
Publisher: CENGAGE L
expand_more
expand_more
format_list_bulleted
Concept explainers
Videos
Question
Chapter 57, Problem 8SQ
(a)
To determine
Explain whether the resistance of the rheostat is to be increased or decreased to increase the generator voltage.
(b)
To determine
Explain the condition of current change in the generator’s shunt field winding to increase the generator voltage.
Expert Solution & Answer
Trending nowThis is a popular solution!
Students have asked these similar questions
i need the answer quickly
A short-shunt compound wound generator has a shunt field resistance of 77 ohms, a
series field resistance of 0.008 ohms, a commutating pole winding resistance of
0.005 ohms, and an armature resistance including brushes of 0.02 ohms. When the
armature current is 128 amperes, the generated emf is 234.5 volts. Calculate the
power
delivered to the load.
note: A commutating pole winding is connected in series with the armature winding.
Draw the circuit
Chapter 57 Solutions
Electric Motor Control
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, electrical-engineering and related others by exploring similar questions and additional content below.Similar questions
- Q2- Indicate whether the following statements are true or false and correct the false statements 1- The brushes of d.c machine always are placed at the magnetic neutral axis 2- The field current of d.c shunt generator is not affected by load current. 3-The armature voltage of d.c series generator is not affected by load current. 4- A lap winding is most suitable for higher voltage rating machines 5- In de generator, the critical resistance can be increased by increasing its speed 6-In LAP winding the front pitch equal to (yr Ye- yb). 7- The speed of d.c series motor is decreased if the armature current is decreased 8- The compensating winding carrying the field current 9- By tapping field method, the speed of d.c series motor can be controlled below rated value 10- To solve the Commutation Problem in small machines, this can be achieved by increasing the brush widtharrow_forwardThe windings of short-shunt compound dc generator have the following resistances: Armature, shunt field, interpole and series field are 0.5 ohm, 253 ohms, 0.2 ohm and 0.15 ohm respectively When the generator delivers 40 amperes at 500 Volts, its total drop is 2 Volts. What is the generated power?arrow_forwardA shunt DC generator has no load terminal voltage of 140V. Armature resistance is 1ohm and shunt field resistance is 50ohms. Calculate: (i) Induced voltage (ii) A load is now connected to the terminals that starts drawing 2A current and terminal voltage drops to 130V. Calculate the new value of the induced voltage Make sure to draw equivalent circuits for (i) and (ii)arrow_forward
- A 10-kw 250-volt compound (long-shunt) generator has a no-load voltage of 230. The shunt field has 800 turns per pole and the seriesfield 8.5 turns per pole. The shunt- and series-field resistances are 80 ohms and 0.07 ohm, respectively. To make the generator flat-compound, it will have a noload voltage of 230 and a full-load voltage of 230; the series field must produce 225 amp-turns. Calculate the total number of ampere-turns provided by each pole at no load and full load.arrow_forwardCalculate the flux per pole required on full-load for a 50 kW, 400 V, 8-pole, 600 r.p.m. d.c. shunt generator with 256 conductors arranged in a lap-connected winding. The armature winding resistances is 0.1 2, the shunt field resistance is 200 2 and there is a brush contact voltage drop of 1 V at each brush on full- 5. load.arrow_forwardQ3-(A)- Indicate whether the following statements are true or false and correct the false statements F-The armature voltage of d.c series generator is not affected by load current. In series d-c generator the field winding will be constructed from high number of turns and high cross- sectional area of wire. If field resistance of a d.c. shunt generator is increased beyond its critical value, the generator output voltage will exceed its rated voltage 4-The inter pole winding is connected in parallel to field windingarrow_forward
- 2. This question is regarding the steady state armature current when dead short circuit occurs across the d.c generator terminals. Pick up the correct statement. (A) For a shunt generator the short circuit armature current will be many times larger than the rated current of the armature. (B) For a separately excited generator the short circuit armature current will be many times larger than the rated current of the armature. (C) For a shunt generator the short circuit armature current will be many times lower thanthe rated current of the armature. (D) For a separately excited generator the short circuit armature current will be many times lower than the rated current of the armature.arrow_forwardThe open circuit characteristics of DC shunt generator starts with some * minimum voltage instead of Zero due to a) Residual armature flux O b) Residual pole flux O c) Magnetic inertia O d) High field circuit resistancearrow_forwardWhy does not the generator voltage increase when the excitation current (Ie) increases over the nominal value?arrow_forward
- load characteristics of d.c shunt generatorarrow_forwardIf the armature resistance of a 3-phase, 318.75 kVA, 2300-V synchronous generator is 0.35 ohms per phase, the synchronous reactance is It is 1.2 ohms. Calculate the excitation voltage and voltage regulation for the following load cases: a) Full load, back power factor of 0.8 and rated voltage. b) Full load, forward power factor of 0.6 and rated voltage.arrow_forwardAn eight-pole, 25-kW, 120-V DC generator has a duplex lap-wound armature, which has 64 coils with 16 turns per coil. Its rated speed is 2400 r/min. (a) How much flux per pole is required to produce the rated voltage in this generator at no-load conditions? (b) What is the current per path in the armature of this generator at the rated load? (c) What is the induced torque in this machine at the rated load? |(d) How many brushes must this motor have? How wide must each one be? (e) If the resistance of this winding is 0.011 2 per turn, what is the armature resistance R of this machine?arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
How does an Alternator Work ?; Author: Lesics;https://www.youtube.com/watch?v=tiKH48EMgKE;License: Standard Youtube License