C Formulas

Question 1

Reduced voltage current

I rv (motor) =
(Current to motor starter)

Answer 1

I fv x % tap

Question 2

Starting line current

I rv (line) =
Current to line at start

Answer 2

I fv x (%tap squared)

Question 3

V at motor =
Starting voltage at motor

Answer 3

V line x tap%

Question 4

Starting current to the motor

I to the motor =

Answer 4

I (in rush at full voltage) x tap%

Question 5

Line current to primary of an auto transformer

I line = S devided by V Line

Question 6

Starting torque

T start rv =

Answer 6

T start fv x (tap% squared)

Question 7

T start (wye start) =

Answer 7

T start (fv delta start) devided by 3