5.8 L: Protection Functions
210 YASKAWA ELECTRIC SIEP C710616 35D YASKAWA AC Drive E1000 Technical Manual
Setting 4: PM motor with variable torque
This setting is for operating a PM motor. PM motors for derated torque have a self-cooling design, so the overload
tolerance drops as the motor slows. Electronic thermal overload is triggered in accordance with the motor overload
characteristics, providing overheat protection across the entire speed range.
■
L1-02: Motor Overload Protection Time
Sets the time it takes the drive to detect motor overheat due to overload. This setting rarely requires adjustment, but
should correlate with the motor overload tolerance protection time for performing a hot start.
Defaulted to operate with an allowance of 150% overload operation for one minute in a hot start.
Figure 5.61 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.
During normal operation, motor overload protection operates in the area between a cold start and a hot start.
• Cold start: Motor protection operation time in response to an overload situation that was suddenly reached when
starting a stationary motor.
• Hot start: Motor protection operation time in response to an overload situation that occurred during sustained
operation at rated current.
Figure 5.61
Figure 5.61 Motor Protection Operation Time
■ Motor Protection Using a Positive Temperature Coefficient (PTC)
A motor PTC can be connected to an analog input of the drive. This input is used by the drive for motor overheat
protection.
When the PTC input signal reaches the motor overheat alarm level, an oH3 alarm will be triggered and the drive will
continue operation as selected in L1-03. When the PTC input signal reaches the overheat fault level, an oH4 fault will be
triggered, a fault signal will be output, and the drive will stop the motor using the stop method determined in L1-04.
Overload Tolerance Cooling Ability Overload Characteristics
Motor is designed to produce 100% torque at base
speed. Built with effective cooling capabilities.
Reaching 100% when operating at below the base
frequency will cause a motor overload fault (oL1).
The drive fault output closes and the motor coasts to
stop.
No. Name Setting Range Default
L1-02 Motor Overload Protection Time 0.1 to 5.0 minutes 1.0 minutes
Continuous
60 s
Motor Speed (%)
Torque (%)
150
10 33 100
120
100
80
50
0.0
Operation time (minutes)
Cold start
Hot start
Motor current (%)
E2-01 = 100% motor current
10
7
3
1
0.4
0.1
0 100 150 200
SIEP_C710616_35.book 210 ページ 2015年11月30日 月曜日 午後2時2分