A brushless dc motor has 3 phases and 4 poles. The generated emf is 220 V rms sinusoidal at 1000 rpm (open circuit voltage when tested as generator with a drive motor). Calculate (a) the emf constant (V/Rad/s); (b) the torque constant (Nm/A) with optimum position feedback angle; (c) the speed/torque curve, if the resistance per phase is 4 ; (d) the supply frequency at 1000 rpm; (e) curves of input power, output power and efficiency against torque, assuming friction and iron losses are zero; (f) the frequency and speed at which X= L is equal to the resistance R, if the phase inductance is 5 mH; (g) what is the effect of (f) on the speed/torque curve i.e. the effect of L>0 and L>R as speed increases?

A brushless dc motor has 3 phases and 4 poles. The generated emf is 220 V rms sinusoidal at 1000 rpm (open circuit voltage when tested as generator with a drive motor). Calculate (a) the emf constant (V/Rad/s); (b) the torque constant (Nm/A) with optimum position feedback angle; (c) the speed/torque curve, if the resistance per phase is 4 ; (d) the supply frequency at 1000 rpm; (e) curves of input power, output power and efficiency against torque, assuming friction and iron losses are zero; (f) the frequency and speed at which X= L is equal to the resistance R, if the phase inductance is 5 mH; (g) what is the effect of (f) on the speed/torque curve i.e. the effect of L>0 and L>R as speed increases?

Introductory Circuit Analysis (13th Edition)

13th Edition

ISBN:9780133923605

Author:Robert L. Boylestad

Publisher:Robert L. Boylestad

Chapter1: Introduction

Section: Chapter Questions

Problem 1P: Visit your local library (at school or home) and describe the extent to which it provides literature...

See similar textbooks

Similar questions

(c) A four-pole, three-phase 415 V, 50 Hz induction motor has a rated rotor speed at 1445 rpm. The motor is connected to a constant torque load. (i) Sketch the IEEE recommended per-phase equivalent circuit for the three- phase induction motor. Label all the key components clearly. (ii) Determine the motor's synchronous speed in rpm, the motor's slip, and the frequency of the rotor current in Hertz.. (iii) If the operating frequency of the motor reduced to 40 Hz and the synchronous and rotor speed difference (n.- n,) is maintained at 55 rpm, determine the new motor's synchronous speed and rotor speed.
(A shunt DC motor has a total resistance value for all conditions as Ra= 2 Q and under full load conditions (nominal load) armature current is Ia = 10 A. The nominal terminal Voltage for the motor is Vr-300 V and total value for field circuit resistance for all conditions is Rf=150 Q. Under full load conditions (nominal load), find the internal generated Voltage (EA), excitation circuit current (field current) (If), (total supply current flow, from electrical source) line current (IL), electrical input power (Pin) supplied from the source. Be careful about your solutions to be written readable and write the answers as it was shown below inside boxes.) EA = If = IH (IL) = Pin =
A 420 Vdc, 8 pole Compound DC motor runs at 729 rev/min when drawing a load of 60 A from the supply when meeting a load demand of 28 kW. The compound motor has a Lap connected armature with 816 conductors. The Armature, Interpole, Series, and Shunt resistances are 0.295 Q, 0.0155 Q, 0.00118 Q, and 147 Q respectively. The series field has 6 turns per pole while the shunt field has 2800 turns per pole. Under full load conditions, the shunt current is 3.75 A, and the Friction and windage loss is Pf/w = 0.782 kW. Consider c =6 for lap winding. Assume constant shunt current and friction and windage loss, determine for a reduced output load of 14.5 kW; (a) The new armature current; (b) The new speed of the motor
The stator resistance of a 1-phase induction motor is 2.5 ohm and its leakage reactance is 2.0 ohm. Onno-load, the motor takes 4 A at 96 V and at 0.25 lagging power factor. The no-load friction andwindage loss is negligible. Under the blocked-rotor condition, the input power is 130 W at 6 A and42 V. obtain the equivalent circuit parameters.
A 220-V Y-connected synchronous motor is drawing 50 A at unity power factor from a 220-V power system. The field current flowing under these conditions is 2.7 A. Its synchronous reactance is 1.4 ohms. Assume a linear open-circuit characteristic. (a) Find phase voltage and induced emf for these conditions. (b) Find the torque angle. (c) What is the maximum power that the machine can handle under these conditions? (d) How much armature current would be required to make the motor operate at 0.80 PF leading?
An armature controlled DC motor has the following parameters: Tf = 0.03 Nm KT = 0.15 Nm/A Imax = 2.4 A KĘ = 0.15 Vs/rad Wmax = 5000 rpm R = 0.8 Ohms 1. Determine the following: (i) The maximum output torque. (ii) The maximum power output. (iii) The maximum armature voltage. (iv) The no load motor speed when e = Emax 2. Plot the following relationships: (i) Torque versus current (ii) Induced voltage versus speed 3. If the above motor is operated at 3000 rpm with a load torque of 0.15 N.m, determine the armature voltage
1. The rated current of 15 hp, 220V separately excited DC motor is- a) 50.87A b) 60.2 A c) 40.31A 2. If the load torque T₁ of induction motor proportional to square of the rated speed, what will be the value of load torque if the motor speed reduces to half rated speed. a) 2-TL. 3. In stator voltage control strategy of induction motor, the variable stator voltage will be: a) above rated voltage b) below than rated voltage e) above and below rated voltage