KB Electronics KBMK-24DF - Manual (Page 11)

11
FIGURE 6
MAXIMUM ALLOWED MOTOR TORQUE VS. SPEED
FIGURE 7
OPEN VENTILATED MOTOR
WITH EXTERNAL FAN COOLING
TEFC and Open Ventilated
Inverter Duty
and TENV
Motors
Fan Cooled
Motors
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 preset level of 160% of the Motor Nameplate Rated Current setting. The factory
setting for motor nameplate current is the drive rated current, which must be set to the actual
motor nameplate current (see Important Application Information (Item 2), on page 3). See Table
2, on page 7. Also see Function No. 0.01, on page 22.
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 the Motor Nameplate Rated Current 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
seconds.
*UL approved as an overload protector for motors.
5 MOUNTING INSTRUCTIONS
It is recommended that the drive be mounted vertically on a flat surface with adequate ventilation. Leave
enough room below the drive to allow for AC line, motor connections, and any other wiring that is required.
Care should be taken to avoid extreme hazardous locations where physical damage can occur. When
mounting the drive in an enclosure, the enclosure should be large enough to allow for proper heat dissipation
so that the ambient temperature does not exceed 45°C (113 °F) at full rating. See Figure 5, on page 10.
WARNING! Do not use this drive in an explosion-proof application.
Be sure the drive is securely mounted.
6 ELECTRICAL CONNECTIONS
See Table 4, for terminal block wire and tightening torque specifications.
WARNING! HIGH VOLTAGE – Read Safety Warning, on page 5, before using the drive.
Disconnect main power before making connections to the drive. To avoid electric shock, be sure to
properly ground the drive.
Application Note: To avoid erratic operation, do not bundle the AC line and motor wires with each other
or with wires from signal following, start/stop contacts, or any other signal wires. Also, do not bundle
motor wires from multiple drives in the same conduit. Use shielded cables on all signal wiring over 12"
(30 cm). The shield should be earth grounded on the drive side only. Connect the drive in accordance
with the National Electrical Code requirements and other local codes that may apply.