** Al-Ameeria Integrated Technical Education
Cluster**

**BTEC Higher National Diploma in**

**Electrical & Electronic Engineering**

** 2^{nd}
semester 2016/2017**

**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
10W. Find the average values
of the load voltage and load current at triggering angles of a=15^{0} and a=75^{0}.

(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=10W and the triggering angle is 30^{0}.

(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=10W from a 380-V, 50-Hz ac supply. Find the average
values of the load voltage and load current at triggering angles of a=15^{0} and a=75^{0}.

(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=10W and the triggering angle is 60^{0}.

(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 0.097W. 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 kf=1.15 V. s /rad.