ECE 482
Electrical Drive Systems
Topic: DC Drives – Rectifier controlled
Q1
(i) Firing angle for rated torque and 750 rpm
A 200 V, 875 rpm, 150 A separately excited dc motor has an armature
resistance of 0.06 Ω. I
...
ECE 482
Electrical Drive Systems
Topic: DC Drives – Rectifier controlled
Q1
(i) Firing angle for rated torque and 750 rpm
A 200 V, 875 rpm, 150 A separately excited dc motor has an armature
resistance of 0.06 Ω. It is fed from a single phase fully controlled
rectifier with an ac voltage source of 220 V, 50 Hz. Assuming
continuous conduction, calculate:
(ii) Firing angle for rated torque and (-500) rpm
(iii) Motor speed for α = 160˚ and rated torque
Q2
A 220 V, 1500 rpm, 10 A separately excited dc motor is fed from a single phase fully controlled rectifier with an ac voltage source of 230 V, 50 Hz. Armature resistance = 2 Ω. Assuming continuous conduction, calculate:
(i) Firing angle for rated torque and 500 rpm
(ii) Firing angle for rated torque and (-1000) rpm
Q3
220 V, 1200 rpm, 15 A separately excited dc motor has armature resistance and inductance of 1.8 Ω and 32 mH respectively. The motor is fed from a single phase fully controlled rectifier with an ac voltage source of 230 V, 50 Hz. Assuming continuous conduction, calculate:
Speed for α = 45˚ and torque = 40 Nm
Q4
Flux as a percent of its rated value when the motor speed is 750 rpm
A 220 V, 600 rpm, 500 A separately excited dc motor has an armature resistance of 0.02 Ω and field resistance of 10 Ω. The load torque is given by the expression: TL = 2000-2N (Nm). Calculate
Q5
Flux as a percent of its rated value when the motor speed is 1500 rpm
A 220 V, 750 rpm, 200 A separately excited dc motor has an armature resistance of 0.05 Ω. The load torque is given by the expression: TL = 500-0.25N (Nm). Calculate
Q6
18
A 220 V, 750 rpm, 200 A separately excited dc motor has an armature resistance of 0.05 Ω. The field winding is also rated for 220 V and has field resistance of 20 Ω. The load torque is given by the expression: TL = 500-0.2N (Nm). Speeds below rated value are obtained by armature voltage control with full field and speeds above rated are obtained by field control at rated armature voltage.
Armature is supplied from a single phase Thyristor based full bridge rectifier from a supply of 250 V, 50 Hz. Field coil of the motor is also fed from a single phase Thyristor based full bridge rectifier from a 250 V, 50 Hz supply.
If the drive operates under continuous conduction mode, calculate the firing delay angle when drive operates at
(i) 600 rpm and (ii) 1200 rpm
Q7
A 220 V, 1500 rpm, 10 A separately excited DC motor has an armature resistance of 10 Ω. It is fed from a single phase fully controlled bridge rectifier with an AC source voltage of 230 V, 50 Hz. Assuming continuous conduction, compute
(i) The motor speed at firing angle of 30˚ and torque of 5 Nm. (ii) Developed torque at firing delay angle of 45˚ and speed of 1000 rpm.
Q8
A 220 V, 1000 rpm, 10 A separately excited DC motor has an armature resistance of 1 Ω. Both the armature and the field windings are fed from single phase fully
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