Maximum Allowed Motor Torque Vs. Speed; Open Ventilated Motor With External Fan Cooling - Baldor SERIES 5 Installation And Operation Manual

If external
provided,
motors can also achieve an
extended speed range at full
rated torque.
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 8.
5.2 ELECTRONIC
OVERLOAD
The drive contains Modified I
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 overshoot function that allows most
motors to develop more than 200% of starting torque.
Standard I
motor current to develop and will turn the drive off after a short period of time. The 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
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. See Section 7.6, on page 23.
*UL approved as an overload protector for motors.
18
FIGURE 7 – MAXIMUM ALLOWED MOTOR TORQUE
INVERTER DUTY
AND TENV MOTORS
100
80
MAXIMUM
60
ALLOWED
MOTOR
40
TORQUE %
20
0
0 10 20 30 40 50 60 70 80 90 100
fan cooling is
open ventilated
A box fan or
MOTOR
PROTECTION:
2
2
t is undesirable because it causes nuisance tripping. It allows a very high
FAN COOLED TEFC AND
OPEN VENTILATED MOTORS
MOTOR SPEED (%)
FIGURE 8 - OPEN VENTILATED MOTOR
WITH EXTERNAL FAN COOLING
t
SPEED
VS.
2
t Timer starts.