A series motor having an armature resistance of 0.1Ω and a field resistance of 0.15Ω, takes 48A at 230V and 720 rpm. The total core and friction losses are 650W. Neglecting stray-load and brush contact losses, the load of the motor is reduced so that the motor now takes 32A. Find the motor speed. 1100rpm 1235rpm 700rpm 600rpm

A series motor having an armature resistance of 0.1Ω and a field resistance of 0.15Ω, takes 48A at 230V and 720 rpm. The total core and friction losses are 650W. Neglecting stray-load and brush contact losses, the load of the motor is reduced so that the motor now takes 32A. Find the motor speed. 1100rpm 1235rpm 700rpm 600rpm

Delmar's Standard Textbook Of Electricity

7th Edition

ISBN:9781337900348

Author:Stephen L. Herman

Publisher:Stephen L. Herman

Chapter32: Three-phase Motors

Section: Chapter Questions

Problem 13RQ: A squirrel-cage induction motor is operating at 1175 RPM and producing a torque of 22 Ib-ft. What is...

See similar textbooks

Similar questions

A 200V long-shunt generator delivers 100A, has an armature resistance of 0.05Ω, a series field resistance of 0.25Ω and a shunt field resistance of 200Ω. If a feeder resistance of 0.05Ω and a brush contact drop of 2.5V are considered, what will be the shunt field current (in Amp)? use two decimal places if the answer is not exact and do not include the unit anymore.
The field and armature resistance of a 400V shunt motor are 200 ohms and 0.1ohm, respectively. The motor takes 30A of current while running at 1000 rpm. If the frictional losses are 400W, determine the motor efficiency.
A dc shunt motor rated at 250V, runs at 1000rpm draws a current of 25A. Determine the speed if the field is weakened by 3% for the line current of 50A. The armature and field resistances are 0.2 and 250 ohms respectively. Brush drop may betaken as 1V per brush.
A short shunt compound generator supplies a current of 100A at 220V. If the resistance of the shunt field is 50Ω, of the armature 0.05Ω, the total brush drop is 2V and the iron and friction losses amount to 1 kW, find the bhp of the engine driving this generator.
The power input to a 500V, 50Hz, 6 pole, 3 squirrel cage induction motor running at975 RPM is 40kW. The stator losses are 1kW and friction and windage losses are 2kW.Find the output power of the motor
A dc shunt motor operating at an armature terminal voltage of 125 V is observed to be operating at a speed of 1180 r/min. When the motor is operated unloaded at the same armature terminal voltage but with an additional resistance of 5Ω in series with the shunt field, the motor speed is observed to be 1250 r/min. i. Calculate the resistance of the series field. ii. Calculate the motor speed which will result if the series resistance is increased from 5Ω to 15Ω.
Solve the following problems. Write the complete solutions in two decimal places. 1. A shunt generator delivers 200 A at 240 V full-load. It has a full-load efficiency of 92%. The stray power loss is 700 watts while the shunt field coil resistance is 50 ohms. Find the armature resistance, armature current when delivering maximum efficiency and the maximum efficiency.
A 320V shunt motor takes a total current of 80A and runs at 1000 rev/min. If the iron, friction and windage losses amount to 1.5 kW, the shunt field resistance is 40 ohm and the armature resistance is 0.2 ohm, determine the overall efficiency of the motor
a shunt-wound motor runs at 600 r.p.m from a 230 V supply when taking a line current of 50 A. its armature and Field resistance are 0.4 ohms and 104.5 ohms respectively. Neglecting the effects of armature reaction and allowing 2 V brush drop, calculate (a) the no-load speed if the no-load line current is 5 A. (b) the resistance to be placed in armature circuit in order to reduce the speed to 500 r.p.m when motor is taking a line current of 50 A . (c) the percentage reduction in the flux per pole in order that the speed maybe 750 r.p.m when the armature is 30 A with no added resistance in the armature circuit.
3. A dc shunt motor operating unloaded at a terminal voltage of 125V at a speed of 1420 rpm. When themotor is operated unloaded at the same terminal voltage but with an additional resistance of 8Ω in serieswith the shunt field, the motor speed is 1560rpm. (Ignore armature reaction and magnetic saturation)a) Calculate the resistance of the shunt field.b) Calculate the motor speed if the series resistance is increased from 8Ω to20Ω. c) With the field resistance at its original value and no series resistance, calculate the motor speed if it isoperated loaded at a terminal voltage of 90 V and a terminal current of 100A.
A 230V shunt motor has an armature resistance of 0.28Ω and a field resistance of 115Ω. At no-load, the line current is 8A and the speed is 2300rpm. What is the speed when the line current is 52A? Assume brush drops of 1V at no-load and 3V at load condition and constant flux density. 2154rpm 2212rpm 2178rpm 2155rpm
A 220V shunt generator has an armature resistance of 0.02ohms and a shunt field resistance of 44ohms. at rate load, the driving engine develops 62.26hp. If the iron and friction losses amount to 1600W, how much is the current delivered to the load at this condition? (Our subject is ELECTRICAL MACHINE 1, and our lesson is Losses and Efficiency on the DC MACHINE) (I need a clean solution ma'am/sir. Thank you do much)