Answer:
a) [tex]n_{s} = 750\,rpm[/tex], b) [tex]n_{r} = 720\,rpm[/tex], c) [tex]n_{p} = 30\,rpm[/tex]
Explanation:
a) Synchronous speed is:
[tex]n_{s} = f\cdot \frac{60}{n_{poles}}[/tex]
[tex]n_{s} = (50\,hz)\cdot \left(\frac{60}{4}\right)[/tex]
[tex]n_{s} = 750\,rpm[/tex]
b) Actual motor speed is:
[tex]S = \frac{n_{s}-n_{r}}{n_{s}} \times 100\%[/tex]
[tex]n_{r} = \left(1-\frac{S}{100}\right)\cdot n_{s}[/tex]
[tex]n_{r} = \left( 1 - \frac{4}{100} \right)\cdot 750\,rpm[/tex]
[tex]n_{r} = 720\,rpm[/tex]
c) Slip speed is:
[tex]n_{p} = n_{s} - n_{r}[/tex]
[tex]n_{p} = 750\,rpm - 720\,rpm[/tex]
[tex]n_{p} = 30\,rpm[/tex]
Answer:
Explanation:
Given:
Number of poles, np = 4 poles
E = 480 V
Frequency, f = 50 Hz
Slip, s = 4%
A.
Speed, Vs = 120 x Frequency (Hz)/number of poles
= 120 × 50/4
= 1500 rpm
B.
Actual motor speed, V = Vs × (1 - s)
V = 1500 × (1 - 0.04)
= 1440 rpm
C.
Slip speed, s = Vs - V
= 1500 - 1440
= 60 rpm
