Example, Determining the start-stop frequency – Festo Шаговые моторы MTRE-ST User Manual

Page 31

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MTRE−ST42−48S−..

Festo MTRE−ST42−48S−.. 0503b English

31

Example

Fig. 4:

upper graph S1 − full step / lower graph S2 − half step M = Torque, n = Speed

The characteristic curve shows the maximum speed that can be run at full or half
step, depending on the set torque. (In the example around 1100 RPM at half step)

Determining the start−stop frequency

It is advantageous to set the start−stop frequency as high as possible since resonĆ
ance leading to losses of step can occur especially in the lower frequency areas.
The start−stop frequency is increased until the drive loses steps when starting.
Then the start−stop frequency is reduced again by a good 20% to ensure that no
steps are lost during acceleration. A starting value of 400 Hz for small drives and
around 200 Hz for large drives can be assumed.

How can incidences of resonance be suppressed? Tips and tricks!

S

Half step instead of full step.
Half step here is better than full step. The two−phase stepping motor shows
generally good run characteristics at half step.

S

Set phase current lower (to the value actually required).
While this reduces the system’s stiffness, it also reduces its tendency to oscilĆ
late.

S

Operating frequencies not equal to resonance frequencies.
The operating frequency is often near the resonance frequency or is a multiple

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