4.3 UL Standards
280 YASKAWA ELECTRIC SIEP C710617 05F YASKAWA AC Drive GA700 Technical Manual
Load Tolerance Cooling Capability
Overload Characteristics
(at 100% motor load)
This motor is designed to withstand
increased temperatures during continuous
operation in the low speed range (0.2% base
frequency).
The motor operates continuously at 0.2% to
100% rated speed. Operating slower than
0.2% speed at 100% load will cause motor
overload.
6 : Variable Torque (50Hz)
Use this setting for general-purpose motors with a base frequency of 50 Hz.
The overload tolerance decreases as motor speed decreases because the cooling fan speed decreases and the ability
of the motor to cool decreases in the low speed range.
The overload tolerance characteristics of the motor change the trigger point for the electronic thermal protector.
This provides motor overload protection from low speed to high speed across the full speed range.
Load Tolerance Cooling Capability
Overload Characteristics
(at 100% motor load)
This motor is designed to operate with
commercial line power. Operate at a 50 Hz
base frequency to maximize the motor
cooling ability.
If the motor operates at frequencies less than
commercial line power, the drive will detect
oL1. The drive triggers a fault relay output
and the motor coasts to stop.
■ L1-02: Motor Overload Protection Time
No.
(Hex.)
Name Description
Default
(Range)
L1-02
(0481)
Motor Overload
Protection Time
Sets the operation time for the electronic thermal protector of the drive to
prevent damage to the motor. Usually it is not necessary to change this
setting.
1.0 min
(0.1 - 5.0 min)
Set the overload tolerance time to the length of time that the motor can operate at 150% load from continuous
operation at 100% load.
When the motor operates at 150% load continuously for 1 minute after continuous operation at 100% load (hot
start), the default setting triggers the electronic thermal protector.
Figure 4.23 shows an example of the electronic thermal protector operation time. Motor overload protection
operates in the range between a cold start and a hot start.
This example shows a general-purpose motor operating at the base frequency with L1-02 set to 1.0 min.
• Cold start
Shows the motor protection operation time characteristics when the overload occurs immediately after starting
operation from a complete stop.
• Hot start
Shows the motor protection operation time characteristics when overload occurs from continuous operation
below the motor rated current.
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