(C&G 203 ?) Motor & Other Questions..

[Jono Pashley]

Except your only given a voltage, your not told if its a three phase supply or not.

 

[Andy™]

11. Power = V X I X pfPower = 400 x 50 x 0.8

Power = 16KW

Unless it specifically mentions three phase id be unsure of using the three phase calc.

12. using Xc Formula of 1 / 2 x crbvcurbvubruvbruvb x f x c

im getting 3183.1 ohms, which im unsure of so can someone else check that.

16. Sync Speed = Frequency / Pairs of Poles

Sync Speed = 50/2

Convert to rpm = sync speed x 60 = 1500

4% of 1500 is 60

1500-60 = 1440rpm

i agree with all those answers. just be aware on the 3 phase as others have already mentioned

 

[msb2003]

Q11. Voltage multiplied by the current will give you apparent power. Multiply this by the p.f. to work out the true power.

I wouldn't include the 3 phase calculation as it doesn't mention its 3 phase! C&G could give any voltages to work with as the calculations hold true at any voltage.

 

[a1pacino]

19. The number of pair windings in a single phase capacitor start induction motor is:

A One

B Two

C Three

D Four

is it the number of pairs of windings or pair windings? as if it was pairs it would be 1, if it was number of windings it would be 2 as it has start and run winding? ?:|

 

[david-sam]

yes the correct answer to question 12 is 3.18kohms or 3183 ohms