YASKAWA U1000 Series Technical Manual page 298

5.8 L: Protection Functions
Setting 5: Constant torque PM motors (constant torque range of 1:500)
Sets protection characteristics needed when driving a PM with constant torque. These motors allow for a speed control
from 0.2% to 100% when operating with 100% load. Slower speeds with 100% load will trigger overload.
Overload Tolerance
Instantaneous rating (60 s)
150
125
115
100
83
77
67
0 0.2
Percent of base speed (%)
Setting 6: General-purpose motor (50 Hz)
Because the motor (50 Hz) is self-cooled, the overload tolerance drops when the motor speed is lowered. The drive
appropriately adjusts the electrothermal trigger point according to the motor overload characteristics, protecting the
motor from overheat throughout the entire speed range.
Overload Tolerance
150
Rated Speed=100% Speed
60 s
A: Max. speed for 200LJ and above
B: Max. speed for 160MJ to 180 LJ
C: Max. speed for 132MJ and below
100
90
Continuous
50
A
B
05 33 100 120 167 200
Speed (%)
■ L1-02: Motor Overload Protection Time
There is normally no need to change this parameter from the default value. Sets the time it takes the drive to detect motor
overheat due to overload. If the motor overload tolerance protection time when an overload of 150% is imposed after
continuous operation at 100% is clear, set that time as the value.
No.
L1-02
Defaulted to operate with an allowance of 150% overload operation for one minute in a hot start; after continuous
operation at 100%.
• Figure 5.88 shows an example of the electrothermal protection operation time using a general-purpose motor
operating at 60 Hz with L1-02 set to one minute.
Motor overload protection operates in the area between a cold start and a hot start.
• Cold start: Characteristics of motor protection operation time in response to an overload situation that was suddenly
reached when starting a stationary motor.
• Hot start: Characteristics of motor protection operation time in response to an overload situation that occurred while
the motor was operating continuously at or below its rated current.
298
100 120 130 150
C
Name
Motor Overload Protection Time
Cooling Ability
Motor is designed to effectively cool itself at
ultra-low speeds (about 0.2% of base speed).
Cooling Ability
Motor designed to operate from line power.
Motor cooling is most effective when running at
rated base frequency (check the motor nameplate or
specifications).
YASKAWA ELECTRIC SIEP C710636 02B YASKAWA U1000 Technical Manual
Overload Characteristics
Continuous operation with 100% load from 0.2% to
100% of base speed.
Overload Characteristics
Continuous operation at less than line power
frequency with 100% load can trigger motor
overload (oL1). A fault is output and the motor will
coast to stop.
Setting Range
0.1 to 5.0 minutes
Default
1.0 minutes