Electric Motors - Acceleration time:
Acceleration time for electric motors is directly proportional to
total inertia and inversely proportional to the electric motor torque.
For electric motors with constant acceleration torque, acceleration
where WK2 = rotational inertia in lb-ft2,
(N2 - N1) = the speed difference,
and Tx = acceleration torque in lb-ft. For translating
bodies, acceleration time is:
where W = weight of the load in lb, (S2
- S1) = the translation speed difference, and
Fx = translation force in lb.
An approximation method is necessary to find the electric motor's
acceleration time if acceleration torque is not linear during speed
increase. The quickest method is to break up the speed versus torque
curves of the electric motor and the driven machine into segments
and calculate acceleration time for each segment. Accurate electric
motor acceleration times usually result.