YASKAWA E7U, Programming Manual

Page: 105 / 176

Programming 99
L1 Motor Overload
L1-01 Motor Overload Protection Selection
The Drive has an I
2
t electronic overload protection function, the OL1 fault, for protecting the motor from overheating. The
Drive bases the protection on time, output current, and output frequency. The electronic thermal overload function is
UL-recognized so an external thermal overload relay is not required.
If the Drive is connected to a single motor, the motor overload protection should be enabled (L1-01= “1: Std Fan Cooled”)
unless another means of preventing motor thermal overload is provided.
The time before the OL1 fault will occur changes as the output frequency is reduced. The maximum output current level at
which there is no time limit for operation (the OL Start Point) is different depending on the output frequency. For instance, if
the Drive is being operated at 60 Hz and the output current level is below 106% of the motor’s rated current (E2-01), the Drive
will run without an OL1 fault indefinitely. Once the 106% output current level is exceeded, de-rating of the OL1 time starts.
Fig. 71 Motor Overload Protection Curve
Setting Description
0 Disabled
1 Std Fan Cooled (Enabled) ( factory default )
IMPORTANT
If the Drive is connected to more than one motor for simultaneous operation, the electronic overload protection
should be disabled (L1-01= “0: Disabled”) and each motor should be wired with its own motor thermal overload.
0
88%
106%
20
60
Output Frequency
(Hz)
OL
1 S
tar
t P
oi
nt
(%
o
f F
LA
)
67%
Continuous Operation Area
(%
of
Mo
tor
FLA)