Al-Ameeria Integrated Technical Education Cluster

Activities (3)

(1) A three-phase, half-wave controlled rectifier is fed from 380-V, 50-Hz ac supply. The load is a resistive load of 10Ω. Find the average values of the load voltage and load current at triggering angles of α=15° and α=75°.

(2) Repeat Prob.(7), if the load is highly inductive load.

(3) A three-phase, half-wave controlled rectifier is fed from 380-V, 50-Hz ac supply. The load is a highly inductive load of R=10Ω and the triggering angle is 300.

(i) Draw the waveforms of the load voltage and thyristor voltage.

(ii) Compute the load power and the supply power factor

(iii) Determine the rating of the thyristor.

(4) A three-phase, fully controlled bridge rectifiers feeds a resistive load of R=10Ω from a 380-V, 50-Hz ac supply. Find the average values of the load voltage and load current at triggering angles of α=15° and α=75°.

(5) Repeat Prob.(4), if the load is highly inductive load.

(6) A three-phase, fully controlled bridge rectifiers is fed from 380-V, 50-Hz ac supply. The load is a highly inductive load of R=10Ω and the triggering angle is 600.

(i) Draw the waveforms of the load voltage and thyristor voltage.

(ii) Compute the load power and the supply power factor

(iii) Determine the rating of the thyristor.

(7) A 40-kW, 200-V, permanent-magnet has an armature-circuit resistance of 0.097Ω. The motor is fed from a single phase, fully-controlled rectifier bridge and the ac supply is 240-V, 60-Hz. If the efficiency of the motor at rated conditions is 96.7%.

(i) Find the triggering angle.

(ii) The motor speed if the motor constant is kΦ=1.15 V. s /rad.