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posted by  R.K. on 7/23/2008 4:31:59 AM  |  status: Live  

asynchronous Machine

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Question Details:
A 4-pole induction motor delivers 40 h.p. at the shaft at the speed of 1430 r.p.m. on 500-V, 50 Hz. supply . The  mechanical losses total 3 h.p.and the power factor  is 0.9 .Calculate for this load (a) the slip (b) The stator copper loss (c) The total power input if the stator losses are 2000 W, (d) The efficiency (e) The line current (f) The number of  complete cycles per minute of the rotor e.m.f.

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posted by boon(EE-SME) on 7/23/2008 7:43:17 AM  |  status: Live
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Response Details:
Given,
Poles,
Motor output,
Speed,
Voltage,
Frequency,
Mechanical losses
Power factor,
Stator losses,
We know
Synshronous speed,
(a)
Slip,
(b)
Mecahnical power developed  = motor output + medchanical losses
Rotor input = mechanical power/(1-s)
Rotor copper losses  = slip*Rotor input
(c)
Total power input = rotor input + stator losses
(d)
Efficiency = motor output / input power
(e)
Line current,
(f)
The number of  complete cycles per minute of the rotor e.m.f. is
Hope this helps you...
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