Yaskawa G7 Drive - Manual (Page 270)

Machine Protection
6-
53
‹ Setting Motor Protection Operation Time
Set the motor protection operation time in L1-02.
If, after operating the motor continuously at the rated current, a 150% overload is experienced, set the (hot
start) electronic thermal protection operation time. The factory setting is resistance to 150% for 60 seconds.
The following diagram shows an example of the characteristics of the electronic thermal protection operation
time (L1-02 = 1.0 min., operation at 60Hz, general-purpose motor characteristics, when L1-01 is set to 1)
Fig 6.39 Motor Protection Operation Time
„ Setting Precautions
• If multiple motors are connected to one Drive, set parameter L1-01 to 0 (disabled). To protect the motor,
install a thermal relay in the motor power cable, and perform overload protection on each motor.
• With applications where the power supply is often turned ON and OFF, there is a risk that the circuit cannot be pro-
tected even if this parameter has been set to 1 (enabled), because the thermal value will be reset.
• To detect overloads in good time, set the set value in parameter L1-02 to a low setting.
• When using a general-purpose motor (standard motor), the cooling ability will be lowered by f
1/4
(fre-
quency). Consequently, the frequency may cause motor overload protection (OL1) to occur, even below
the rated current. If operating using the rated current at a low frequency, use a special motor.
„ Setting the Motor Overload Pre-Alarm
If the motor overload protection function is enabled (i.e., L1-01 is set to other than 0) and you set H2-01 to
H2-05 (multi-function output terminals M1-M2, M3-M4, M5-M6, P3-C3, and P4-C4 function selection) to
1F (motor overload OL1 pre-alarm), the motor overload pre-alarm will be enabled. If the electronic thermal
value reaches minimum 90% of the overload detection level, the output terminal that has been set will be
turned ON.
Operating time (min.)
Cold start
Hot start
Motor current (%)
E2-01 is set to 100%