4.2
Electronic Motor Overload Protection –
The drive contains Modified I
2
t Overload
Protection.* Part of this function consists of a Current Limit (CL) circuit, which limits the drive
current to a factory preset level of 160% of the rated drive current. The CL Trimpot is used to
recalibrate the drive current from 60% thru 200%. The Power Start™ circuit provides an over-
shoot function that allows most motors to develop more than 200% of starting torque and
breakdown torque.
Standard I
2
t is undesirable because it causes nuisance tripping. It allows a very high motor
current to develop and will turn the drive off after a short period of time. KB’s RMS Current
Limit Circuit avoids this nuisance tripping while providing maximum motor protection.
If the motor is overloaded to 120% of full load (75% of the CL setting), the I
2
t Timer starts. If
the motor continues to be overloaded at the 120% level, the timer will shut down the drive
after 30 minutes. If the motor is overloaded to 160% of full load, the drive will trip in 6 sec-
onds.
*UL approved as an overload protector for motors.
5
FINGER-SAFE COVER
The drive is designed with an IP-20 Finger-Safe Cover which provides protection against accidental
contact with high voltage.
WARNING! Disconnect main power when removing or installing the Finger-Safe Cover.
WARNING! To prevent accidental contact with high voltage, it is required that the
Finger-Safe Cover be properly installed onto the drive after all wiring and setup is
complete. It offers protection against electric shock which limits the potential liability to
the equipment manufacturer and installer.
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