1. A 300 V compound motor has armature resistance 0.18 Ω, series field resistance 0.3 Ω...
1. A 300 V compound motor has armature resistance 0.18 Ω, series field resistance 0.3 Ω and shunt field resistance 100 Ω. The rotational losses are 200 W. On full load the line current is 25 A and the motor runs at 1800 rpm. Determine:
(i) the developed mechanical power
(ii) the output power
(iii) the output torque
(iv) the efficiency at full load
2. A 120 V series motor has 0.2 Ω field resistance. On full load, the line current is 16.5 A. The output power is 1500 W and rotational loss is 150 W. Find the value of armature resistance.
3. A compound DC motor rated at 415 V, 6 HP, 2000 rpm has armature resistance 0.18 Ω, series field resistance 0.3 Ω and shunt field resistance 100 Ω. The rotational losses are 200 W. The full load line current is 40 A.
(i) Find the developed mechanical power.
(ii) Find the output power.
(iii) Find the load torque.
(iv) Find the efficiency of the motor.
(v) Draw the power flow diagram for this type of motor.
4. A DC series generator delivers 100 kW at 10 kV to a load. The armature resistance is 20 Ω and the field resistance is 50 Ω. Calculate:
(i) the generated emf, Eg
(ii) the input power if the stray and friction losses are 400 W.
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1. A 300 V compound motor has armature resistance 0.18 Ω, series
field resistance 0.3 Ω...
A 30 hp, 240 V, 1150 rpm de shunt motor operating at rated conditions has an efficiency of 88.5%. The armature circuit resistance and field circuit resistance are 0.096 Ω and 936 Ω respectively. Calc...
A 30 hp, 240 V, 1150 rpm de shunt motor operating at rated conditions has an efficiency of 88.5%. The armature circuit resistance and field circuit resistance are 0.096 Ω and 936 Ω respectively. Calculate the following: (a) the armature current; b) the output torque (c) the mechanical developed power (d) the mechanical developed torque; and, e) the external resistance required in series with the armature to limit the starting torque to 200 % of rated torque. If the load...
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A d.c shunt motor has armature and field resistance of 0.2 Ω and 110 Ω respectively. The motor is running at 1200 rpm and drawing 15 A from 110 V supply. If the field resistance is decreased by 10%, calculate the new steady state armature current and speed of the motor. Assume the load torque to be constant.
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A 30 hp, 240 V, 1150 rpm de shunt motor operating at rated conditions has an efficiency of 88.5%. The armature circuit resistance and field circuit resistance are 0.096 Ω and 936 Ω respectively. Calculate the following: (a) the armature current; b) the output torque (c) the mechanical developed power (d) the mechanical developed torque; and, e) the external resistance required in series with the armature to limit the starting torque to 200 % of rated torque. If the load...
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