The shunt motor shown in Fig. 33-5 has an armature resistance of 0.25 and a field

The shunt motor shown in Fig. 33-5 has an armature resistance of 0.25 Ω and a field resistance of 150 Ω. It is connected across 120- V mains and is generating a back emf of 115 V. Compute: 

(a) The armature current Ia, the field current If, and the total current It taken by the motor; 

(b) The total power taken by the motor; 

(c) The power lost in heat in the armature and field circuits; 

(d) The electrical efficiency of this machine (when only heat losses in the armature and field are considered).

Transcribed Image Text:

Field 150 92 000000- Armature 0.25 92 Fig. 33-5 120 V