(adsbygoogle = window.adsbygoogle || []).push({}); Questions about shunt motor

1. The problem statement, all variables and given/known data

Good evening everyone, I've got the following question :

A 120-V dc shunt motor having an armature circuit resistance of 0.2 Ω and a field circuit resistance of 60 Ω, draws a line current of 40 A at full-load. The rated full-load speed is 1800 rpm. If the magnetic saturation and armature reaction are negligible, calculate

a. The field current, If.

b. The full-load armature current, IaFL.

c. The full-load back EMF, EbFL.

d. The full-load developed power, PdFL.

e. The full-load developed torque, TdFL.

f. The half-full load armature current, Ia1/2FL(Td1/2FL= 1/2TdFL).

g. The half-full load back EMF, Eb1/2FL.

h. The motor speed at half-full load, n1/2FL.

i. The armature current at the instant of starting, Iastarting.

j. The value of the external resistance, Rext that should be connected in series with the armature winding to reduce the starting current to 200% of the full-load current.2. Relevant equations

3. The attempt at a solution

Lets see,, I solved until part (e) and I didn't understand the rest.

My questions are :

(d), does it mean P = E(armature)*I(armature) ?? and BTW the word Full-load developed powermeans output ?? developed

(f) what doesmean ?? what should I do to make the load half ?? half-full load armature current

(i)does it equal 0 ?? and if it does why and if not why not ?? i. The armature current at the instant of starting, Ia(starting)

these are my questions for now ,, I'll try solving (j) after solving those ,, so I need help

**Physics Forums - The Fusion of Science and Community**

# Question about shunt motor

Know someone interested in this topic? Share a link to this question via email,
Google+,
Twitter, or
Facebook

Have something to add?

- Similar discussions for: Question about shunt motor

Loading...

**Physics Forums - The Fusion of Science and Community**