KB Electronics KBMK-24DF - Manual (Page 10)

10
FIGURE 5
MECHANICAL SPECIFICATIONS
9.0
0.35
109
4.30
126
27.9
1.10
5.10
130
0.2
5.08
0.39
9.91
4X Ø
4X Ø
7.00
178
1.75
44.5
7.6
0.30
4.95
3.20
81.3
5.10
130
0.95
24.1 0.95
24.1
25.4
1.45
36.8
1.00
2.35
59.7
4.15
105
4 IMPORTANT APPLICATION INFORMATION
4.1 MOTOR WITH EXTERNAL FAN COOLING: Most totally enclosed fan-cooled (TEFC) and open
ventilated 3-phase AC induction motors will overheat if used beyond a limited speed range at full
torque. Therefore, it is necessary to reduce motor load as speed is decreased.
Note: Some fan-cooled motors can be used over a wider speed range. Consult the motor
manufacturer for details.
WARNING! Some motors have low speed characteristics, which cause overheating and
winding failure under light load or no load conditions. If the motor is operated in this manner for
an extended period of time, it is recommended that the unloaded motor current be checked from
2 – 15 Hz (60 – 450 RPM) to ensure motor current does not exceed the nameplate rating. If the
motor current exceeds the nameplate rating, the Boost value may have to be decreased (see
Function No. 3.11). Do not use motor if the motor current exceeds the nameplate rating.
It is recommended that the drive be used with Inverter Duty or TENV motors.
Inverter duty and most totally enclosed non-ventilated (TENV) motors can provide full rated
torque over an extended speed range without overheating. See Figure 6, on page 11.
If external fan cooling is provided, open ventilated motors can also achieve an extended speed
range at full rated torque. A box fan or blower with a minimum of 100 CFM per HP is
recommended. Mount the fan or blower so the motor is surrounded by the airflow. See Figure 7,
on page 11.