phytron
41
MA 2107-A005 EN
The stepper motor phase current decreases with increasing step frequency caused by the
counter-electromotive force of the motor. The overdrive function compensates the
decrease of current and torque. The phase current is increased by about 40 %. The table
below shows the frequency values for switching on and off the overdrive function with
different step resolutions:
Step resolution
Input control pulse frequency
Overdrive
on
at > Overdrive
off
at <
1/1
1 kHz
0.9 kHz
1/2
2 kHz
1.8 kHz
1/4
4 kHz
3.6 kHz
1/5
5 kHz
4.5 kHz
1/10
10 kHz
9.0 kHz
1/20
20 kHz
18.0 kHz
A higher torque in the middle and high frequency ranges is effected.
Fig. 23 shows a phase current diagram below and above the Overdrive activation
frequency in Full step- and 1/10-step modes.