A 240-V, 100 A armature full-load line current, 1800 RPM, Shunt DC motor is considered in this problem. Its characteristics are given below: RA = 0.20 2 RF = 150 2 NF = 2000 turns This motor has compensating windings and interpoles. The magnetization curve for this motor at 1800 RPM is shown in a tabular form below: 0.1 0.2 0.4 0.5 0.6 0.8 1.0 | 1.2 2.2 2.4 110| 135 160 205 235 255 | 275 | 285 | 288 290 291 1.6| 1.8 2.0 If,A EA,V 6.0 25 | 50 For Radi between 0 2 and 2502, find the range of speed of this motor if the armature current I= 66 Amperes. Select one: O a. Range of speed between 1218 RPM and 2130 RPM O b. Range of speed between 1200 RPM and 1820 RPM O c. Range of speed between 1484 RPM and 2551 RPM O d. None

The relation between armature torque and armature current of a DC motor is Parabolic Linear Inverse Exponential

22. A) Why is the power factor of a lightly loaded 3-phase squirrel-cage induction motor very low? a) most of the power supplied to the motor at light loads is magnetization or inductive power b) most of the power supplied to the motor at light loads is resistive power c) most of the power supplied to the motor at light loads is capacitive power d) none of the above B) What happens to the power factor as load is increased on the motor? a) the power factor increases b) the power factor deceases c) remains the same

A DC motor should be operated in a strong field which is due to the What happens to if suddenly goes a) nothing, it continues rotating b) it over speeds c) it stops rotating current if moter if rotating to zero. as before

The armature resistance of a shunt motor fed from a 220 Volt DC source is 5 ohms and the resistance of the excitation winding is R ohm and it rotates stably. Then, a resistance of R ohm is added to the excitation circuit (a resistor with the same value as the winding resistance) to control the speed. How many RPM is the motor in the last state in steady state.Mechanical losses will be neglected, motor magnetically linear, no saturation, temperature change will be neglected.Armature current = Ia = 4 ALoad torque=Tload= 7 Nm

In order to get higher speed of Dc motor the ..... ....... voltage supply most be low back emf (Eb) most be high O frequency most be constant

A 200-V, 100 A armature full-load line current, 1800 RPM. hunt DC motor is considered in this problem. Its characteristics are given below: RA=0.20 52 RE 50 $2 NF-2000 turns This motor has compensating windings and interpoles. The magnetization curve for this motor at 1800 RPM is shown in a tabular form below If.A 0 0.1 0.2 0.4 0.5 0.6 0.8 1.0 1.2 1.6 1.8 2.0 2.2 2.4 EA-V 6.0 25 50 110 135 160 205 235 255 275 285 288 290 291 For Rad between 50 52 and 450 2. find the range of no-load speed of this motor. Answer: No-load Speed Range from RPM to RPM.

A 3-phase, 48 kW, start-connected permanent magnet (PM) motor has a rated speed of 6600 rpm when supplied from a 110 Hz supply. The d-axis and q-axis inductances are La= 3.5mH and Lg= 4.7mH, respectively. The armature resistance and rotational losses are negligible. The motor operates without field weakening up to 6600 rpm, and a negative direct-axis current is imposed if the motor operates at speeds above 6600 rpm. The no-load terminal line-to-line voltage at 5000 rpm is 420 V (RMS). a. Determine the permanent magnet flux linkage. b. Calculate the rated phase current. c. Calculate the rated line to line voltage of the PM motor. с. d. At a speed of 7300 rpm, the PM motor operates in field weakening mode with a direct axis current of -30A and produces a torque of 30 Nm. Determine the per-phase current at this operating condition.

a 220 V dc shunt motor has armature resistance 0.23 ohm, on load it takes armature current 40 A and turnes at 720 rpm, if the flux of motor is reduced by 10% without changing the load torque . Find the new speed of the motor.

A 3 phase, 1500 rpm, 2200 V, star connected synchronous motor has an impedance of 0.4+j90 per phase. At some excitation 2900 V is induced in the armature. Find the maximum torque developed by motor before the motor breaks out of synchronism. Also find the load angle this time.