YASKAWA GA800 Technical Reference page 962

12.9 L: Protection Functions
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 overheat protection from low speed to high speed across the full speed range.
Load Tolerance
■
L1-02: Motor Overload Protection Time
No.
Name
(Hex.)
L1-02 Motor Overload Protection
Time
(0481)
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 12.122 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.
Figure 12.122 Protection Operation Time for a General-purpose Motor at Rated Output Frequency
962
Cooling Capability
This motor is designed to operate with commercial line
power. Operate at a 50 Hz base frequency to maximize the
motor cooling ability.
V/f CL-V/f OLV CLV AOLV
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.
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.
Description
OLV/PM AOLV/PM CLV/PM EZOLV OLV/PM
YASKAWA SIEPC71061737D GA800 Drive Technical Reference
Overload Characteristics
(at 100% motor load)
Default
(Range)
1.0 min
(0.1 - 5.0 min)