5-21
The figure below shows operating characteristics of the electronic thermal overload protection
when F10 = 1. The characteristic factors
α
1 through
α
3 as well as their corresponding
switching frequencies f
2
and f
3
vary with the characteristics of the motor. The tables below list
the factors of the motor selected by P99 (Motor 1 Selection).
motor characteristic factor
factor (%)
Cooling Characteristics of Motor with Shaft-driven Cooling Fan
Nominal Applied Motor and Characteristic Factors when P99 (Motor 1 selection) = 0 or 4
Output frequency for
Characteristic
Nominal
applied
Thermal time
Output current
moto
(kW)
for setting the
r
constant
τ
(Factory default)
thermal time
constant (Imax)
f
2
f
3
α
1
α
2
α
3
0.1 to 0.75
75
85
100
7
85
100
7 Hz
85
1.5 to 3.
5.5 to 11
6 Hz
90
95
100
15 7
Hz
85
85
100
5 min
Rated current
×
150%
5 Hz
18.5, 22
5 Hz
92
100
100
Nomin
or 3
al Applied Motor and Characteristic Factors when P99 (Motor 1 Selection) = 1
Output frequency for
motor characteristic factor
Characteristic
factor (%)
Nominal
applied
Thermal time
constant
τ
Output current
for setting the
motor
(kW)
(Factory default)
thermal time
constant (Imax)
f
2
f
3
α
α
α
1
2
3
0.1 to 2
×
33%
2
5 min
Rated current
×
150%
Base
frequency
×
33%
Base
frequency
69
90
90
Overload detection level (F11)
F11 specifies the level at which the electronic thermal ov
tection becomes activated.
In general, set
frequency (i.e. 1.0 to
1.1 multiple of
ic thermal overload
protec
, set
erload pro
F11 to the rated current of motor when driven at the base
the rated current of motor 1 (P03)). To disable the electron
tion
F11 to "0.00: Disable."
