Method 2: Characteristic curve for asynchronous drives

Asynchronous motors are often used for spindle drives. You can achieve optimised adaptation to typical characteristic of such spindle drives using the speed-dependent spindle acceleration curve a=f(n) shown in the figure below.

Acceleration profile with asynchronous drive curve

Besides the maximum permitted acceleration a__max, speed N₁ for the constant acceleration range, you need only parameterise an additional speed N₂ and the upper minimum acceleration a_min. Acceleration is constant up to the speed N₁. Above N₁, acceleration is proportional to 1/n, and above N₂ it is proportional to 1/n².

N₁=10000 °/s

N₂=20000 °/s,

a_max=16000 °/s²

Above the nominal speed (n_limit) the characteristic profile is as follows:

Curve profile above nominal speed

Parameter

P-AXIS-00202	Curve type 3: Asynchronous drive
P-AXIS-00010	Minimum acceleration a_min
P-AXIS-00240	Maximum acceleration a_max for n<N₁
P-AXIS-00241	Speed limit N₁ for maximum torque
P-AXIS-00242	Speed limit N₂ for maximum output

Programing Example

Parameterisation example

getriebe[0].beschl_kennlinie.typ 3 Asynchronous drive

getriebe[0].beschl_kennlinie.a_max 16000 [°/s²]

getriebe[0].beschl_kennlinie.a_min 4000 [°/s*s]

getriebe[0].beschl_kennlinie.n1 10000000 [10-3 °/s]

getriebe[0].beschl_kennlinie.n2 20000000 [10-3 °/s]