Overcurrent Protection
Definite Time: If the load current exceeds the set value and persists for the duration of the preset overcurrent time, the overload protector trips automatically and resets after 5 minutes. After tripping, the protector displays the current value of the phase with the highest current. Overcurrent time adjustment range: 0.2–30s; repeatability error: ±5%; setting error: ±10%.
Inverse Time: If the load current exceeds the set value and persists for a duration determined by the selected trip class (Curves 1–4) and the ratio of the load current to the set current, the overload protector trips automatically and resets after 5 minutes. After tripping, the protector displays the current value of the phase with the highest current.
Short-Circuit Protection
If the ratio of the load current to the set current exceeds a specific threshold (known as the instantaneous trip multiplier), the condition is treated as a short circuit, and the overload protector trips within 0.5 seconds. Adjustment range for the instantaneous trip multiplier:
Wound-rotor motors: 2–4.5 times.
Squirrel-cage motors: 2–9 times.
Other electromechanical equipment: Select based on the above two categories.
After tripping, the digital display shows "SHORT," and the instantaneous trip multiplier indicator lights up.
Phase Loss Protection
If the current in any of the three phases drops below one-third of the minimum current setting and persists for a specific duration (the phase loss time), the overload protector trips automatically. Upon tripping, the digital display shows "PHASE."
Phase Imbalance Protection
If the three-phase current imbalance reaches 50% and persists for a specific duration (the phase imbalance time), the overload protector trips automatically.
Upon tripping, the digital display shows the current value of the phase with the highest current.
Phase Reversal Protection
If the phase sequence of the three-phase power supply is the reverse of the original sequence, the overload protector trips automatically within 0.2 seconds. Upon tripping, the digital display shows the phase reversal indicator "PR."
