A permanent magnet motor equipped with cobalt-samarium magnets loses 3% of its magnetism per 100°C increase in tempera- ture. The motor runs at a no-load speed of 2500 r/min when connected to a 150 V source in an ambient temperature of 22°C. Estimate the speed if the motor is placed in a room where the ambient temperature is 40°C

A permanent magnet motor equipped with cobalt-samarium magnets loses 3% of its magnetism per 100°C increase in tempera- ture. The motor runs at a no-load speed of 2500 r/min when connected to a 150 V source in an ambient temperature of 22°C. Estimate the speed if the motor is placed in a room where the ambient temperature is 40°C

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 universal motor has armature circuit resistance of 15 ohm and inductanceof 0.3H. On being connected to a 220 V dc supply, it draws 1.5 A from themains and runs at 2000 rpm. Find the speed and power factor of the motor,when connected to a 230 V, 25 Hz supply and drawing the same armaturecurrent.
A 250 V, 4 pole wave wound shunt motor has 650 conductors on itsarmature. It has armature and shunt field resistance of 0.75 ohm and 125ohms, respectively. The motor takes a current of 40 A. Estimate its speedand gross torque developed, if it has a flux per pole of 25mWb.
A 4-pole series motor has 800 lap connected armature conductors. At a certain load, the flux per pole is60mWb and the total mechanical torque developed is 400 N-m. Calculate the line current taken by themotor and the speed at which it will run with a back emf of 400 V. Total motor resistance is 4 ohm.
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
An 8 pole DC shunt generator with 900 wave-connected armature conductors supplies 10ohm at 500 V when driven at 500 rpm. The armature resistance 0.4ohm and the field resistance is 250ohm . Determine: . . 2 1.1 The flux per pole 2.1.2 The armature current for maximum efficiency if the rotational losses are 10% of the ar- mature copper losses . 3.2 A series motor runs at 600 rpm while drawing 40-A from 600-V supply. The total re- sistance of the armature and the field is 0.5-ohm. Determine the value of the additional re- sistance required in series with armature to reduce the speed to 450 rpm if the load toque is: 3.2.1 Constant 3.2.2 Proportional to the square of the speed .
3-phase 3730W, 220V, 6-pole and 50 Hz induction motor operates at full load with a slip of 0.025. The sum of the rotational losses including friction + windage losses and other (stray load) losses is 5% of the output power. Find the induced (electromagnetic) moment at full load
X-a). A universal motor's compensating winding can be connected for_________ compensation when supplied with an AC voltage.a) conductive b) inductive c) either "a" or "b" d) neither "a" nor "b"X-b). A universal motor has___________ speed regulation_a) poor b) good c) excellent d) none of the aboveX-c). How may the direction of rotation of a universal motor be reversed?a) by reversing the direction of current flow in the armature conductors b) by reversing the direction of current flow in the field windings c) either "a" or "b" d) neither "a" nor "b"
A three-phase, two-pole, 35 hp, 480 V, 60 Hz, Y-connected induction motor has the following constants in ohms per phase referred to the stator: Rl = 0.322Ω R2 = 0.196 Ω X1 = 0.675Ω X2 = 0.510Ω Xm = 12.5Ω The total rotational losses are 1850 W and are assumed to be constant. The core loss is lumped in with the rotational losses. For a rotor slip of 3% at the rated voltage and rated frequency, determine the following: (a) The speed in rpm and in rad/s (b) The stator current (c) The power factor (d) The developed power and output power (e) The developed torque and output torque (f) The efficiency.
A 55 hp, 440 V, 400 rpm DC shunt motor draws 107 A when operating at rated conditions. The motor has an armature-circuit resistance of 100 mW and a total field-circuit resistance of 55 W. Answer the following and explain why chose that answer. (iv) What is the power developed by the armature? 28 kW 08 kW 76 kW 58 kW 03 kW (v) What is the value of rotational losses for the motor? 1549 W 1793 W 1990 W 4500 W 8248 W (vi) What is the efficiency of the motor? 09% 60% 15% 26% 36%
The rotor of a 6-pole, 50-Hz induction motor is rotated by some means at 1000 r.p.m. Compute (i) rotor voltage (ii) rotor frequency (iii) rotor slip and (iv) torque developed. Can the rotor rotate at this speed by itself?
A 200-V DC shunt motor has the followingparameters:Ra = 0.1Ω Rf = 100Ω When running at 1,100 r/min with no load connectedto the shaft, the motor draws 4 A from the line. FindE and the rotational losses at 1,100 r/min (assumingthat the stray-load losses can be neglected).
Label values of a three-phase asynchronous motor 50 Hp 60-Hz Y / ∆ 800V / 460V 34A / 59A cos (Q) = 0.85 p = 4 nm = 1425 It is given in rpm. a.) Find the value of the total losses of this ASM. b.) If the load moment of this ASM is 240 Nm and the rotor speed is 950 rpm, what is the speed of the rotary magnetic field ? c.) The rotor of this ASM rotates at 2350 rpm and the load moment is 180 Nm. Accordingly, rotary magnetic Find the velocity of the field