Why does the power consumed is always constant even if a fan
speed is altered?
Answer Posted / ramesh kumar k
A Fan is a constant power device... it always consumes the
same power even if the speed is altered because..
The fan basically operates at 230V and its rated current
inorder to decrease the fan speed we drop some voltage in
the resister so the voltage drop across the armature of the
fan is decreased... because some voltage is dropped in the
resistor itself...
Ex.
Approximately to say...
(this is only example to get understand..)
On 5 No. the Var = 230V & Vr = 0V at current I
On 4 No. the Var = 200V & Vr = 30V at current I
on 3 No. the Var = 150V & Vr = 80V at current I
so like this.... the voltage drop is always 230V only but
we force the less voltage to appear at armature to reduce
the speed of the fan by dropping some voltage in the
resister.
hence the power is always = 230V * Rated current
| Is This Answer Correct ? | 8 Yes | 2 No |
Post New Answer View All Answers
Where should the lighting arrestor be placed in distribution lines?
what is the calculation method to design core and winding of a 200kva 3phase distribution transformer?
If not into production, how far did you follow the design and why did not you see it into production?
What are m circles?
what is value of Jin transformer
What is meant by rotor?
How could I get a certificate of competency as Electrical Supervisor? I have completed By BTech in Electrical this year(2012) for VJTI Mumbai Maharashtra. Is it compulsory to be produced while joining?
what is mean by Digital Logic Meter (DLM)
Please tell me in DETAIL about the following 3 types of fuses or recommend me a good power system protection book or a website link ? 1.Dropout Fuse 2.Striker Fuse 3.Empulsive fuse (not sure if its impulsive or explosion fuse , sorry)
What should be the protection scheme for a 15kw, 3-phase motor working in a lathe machine.
please suggest some good universities with low cost iam in totally full confusion so please help me my profile gre 283 and ielts 5.5
Is it required to do earthing in 2nd shop if earthed armoured cable is laid from 1st shop ?
If two Transformers are connected in parallel having impedance of 50KA in both transformers will the impedance increase or decrease after connecting transformers in parallel?
what is rating boiler
What is the range of the stator resistance of 3 phase induction motor?