Year 1 Power and Energy: Electrical Machines

Question 1

State the equation for ideal torque

Answer 1

Torque(Nm) = Volume x Flux Density x Current Loading

Question 2

State the equation that links torque and power

Answer 2

Power = Torque x Angular Velocity

Question 3

State the equation for mechanical power

Answer 3

Force = Power x Speed

Question 4

State the equation for Angular Velocity(m/s)

Answer 4

Angular velocity = (RPM x 2pi)/60

Question 5

For a nameplate, state the equation for used power

Answer 5

Used Power = HP(in W) / NEMA Efficiency

Question 6

State the equation of electrical input power for a 3 phase machine

Answer 6

Electrical input power = Phase x Voltage x Current/ Square root of phase

Question 7

State the equation for back EMF voltage

Answer 7

Back EMF voltage = Power / Armature current