7.7.1.1. Speed compensation for protecting motors at low speed
The inverter comes with an implemented compensation for low speed. If the motor is
driven with frequencies lower than 40 Hz, the speed compensation in 0x2D4B:002
(P308.02)should be set to "On [0]" (default setting). This setting serves to reduce the
release time of the monitoring at low speed to consider the reduced natural ventilation at
AC motors. The speed compensation for UL-compliant operation in 0x2D4B:002 (P308.02)
must be set to "On [0]" as well.
If the speed compensation is activated, the release time is reduced as follows:
• With an output frequency < 40 Hz: Reduced release time to 62.5 % + 37.5 % * output
frequency [Hz] / 40 [Hz]
• With an output frequency ≥ 40 Hz: No reduced release time
The following diagram shows the reduced release time with activated speed
compensation.
• Maximum utilisation 0x2D4B:001 (P308.01) = 150 %
• Speed compensation 0x2D4B:002 (P308.02) = "On [0]"
Output frequency Release time
40 Hz 60 s
30 Hz ≈ 41 s
20 Hz ≈ 31 s
10 Hz ≈ 23 s
The following diagram shows the possible permanent load with activated speed
compensation without the monitoring being triggered.
• Maximum utilisation 0x2D4B:001 (P308.01) = 150 %
• Speed compensation 0x2D4B:002 (P308.02) = "On [0]"
Output frequency Possible permanent load
40 Hz 110 %
30 Hz 99 %
20 Hz 90 %
10 Hz 79 %
To Next Page
Loading...
