5-9
When P99 = 20, 21 (Motor characteristics)
Motor capacity
Thermal time
constant
τ
(Factory
default)
Thermal time
constant setting
Standard current
value Imax
Characteristics coefficient
switch frequency
Characteristics
coefficient
f
2
f
3
1
2
3
18.5 kW to less
than
110 kW
5 min
Continuous
allowance
current value x
150%
Base
frequency ×
33%
Base
frequency
× 83%
53%
85%
95%
110 kW or
above
10 min
53%
85%
90%
When F10=2 is set, cooling effect by output frequency will not decrease, therefore, overload detection level
becomes constant value (F11) without decrease.
Overload detection level (F11)
F11 sets operation level of electronic thermal.
• Data setting range: 1 to 135% of the rated current value of inverter (continuous allowance current value)
Normally, set to the motor continuous allowance current (in general, about 1.0 to 1.1 times of motor rated current)
when operating at base frequency.
For disabling electronic thermal, set F11 = 0.00: Disable.
Thermal time constant (F12)
F12 sets thermal time constant of the motor. For overload detection level that is set by F11, set the electronic
thermal operation time when 150% of current is flowing continuously. Thermal time constant of general-purpose
motor of Fuji Electric and general motors is 5 minutes for 22 kW or lower, and 10 minutes (factory default state) for
30kW or higher.
• Data setting range: 0.5 to 75.0 (min)
(Example) When the data of function code F12 is set to "5" (5 minutes).
As shown in the diagram below, when 150% of current of operation level that was set flows for 5 minutes, motor
overload (alarm
0l1
) protection function will operate. In addition, with 120%, it operates after 12.5 minutes.
The time when alarm actually occurs is shorter than the set data because the time until the current reaches 150%
level after exceeding the continuous allowance current (100%) is considered.
<Example of current-operation time characteristics>
Op
e
ra
tion
t
ime
(m
in.
)
(Output current / Detection level current) x 100 (%)
Changed
with F12
Summary of Contents for Frenic-Sce
Page 10: ......
