Chapter 4 Parameters
4-112
40
20
60
80
100
25
50
100
150
rated frequency of the motor %
ra
te
d
c
u
rre
n
t o
f t
h
e
m
o
to
r%
Standard motor
(self-cooled by fan)
rated frequency of the motor %
ra
te
d c
u
rr
e
n
t o
f th
e m
o
to
r%
Special Motor
(forced external cooling)
25
50
100
150
40
20
60
80
100
NOTE
When the standard motor operates in low speed with rated current, the motor overload protection will
occur easily. Thus, please use the special motor when operates in low speed with rated current.
Refer to Appendix C.3 How to choose a suitable motor for motor selection.
06.07
Electronic Thermal Characteristic
Unit: second
Settings
30 to 600 sec
Factory Setting: 60
The parameter determines the time required for activating the I
2
t electronic thermal protection
function by the output frequency/current of the AC motor drive and operation time to prevent
motor from overheating.
The electronic thermal overload relay acts by Pr.06.06 setting:
1. Pr.06.06 is set to 0(Operate with a Standard Motor (self-cooled by fan)): when the output
current is greater than (Pr.07.00 Motor Rated Current (Motor 0)X (the corresponding motor
rated current % of motor rated frequency in standard motor figure in Pr.06.06) X150%), the AC
motor drive will start to count time. When accumulated time exceeds Pr.06.07(Electronic
Thermal Characteristic) setting, the electronic thermal overload relay protection (OL1) will be
ON.
2. Pr.06.06 is set to 1(Operate with a Special Motor (forced external cooling)): when the output
current is greater than (Pr.07.00 Motor Rated Current (Motor 0)X (the corresponding motor
rated current % of motor rated frequency in special motor figure in Pr.06.06) X150%), the AC
motor drive will start to count time. When accumulated time exceeds Pr.06.07(Electronic
Thermal Characteristic) setting, the electronic thermal overload relay protection (OL1) will be
ON.
The actual action time of electronic thermal characteristic will be adjusted by the output current
of the AC motor drive (motor load rate %). For large current, it needs short time to activate the
I
2
t electronic thermal protection function. For small current, it needs long time to activate the I
2
t
electronic thermal protection function as shown in the following figure.
Related parameters: Pr.06.06(Electronic Thermal Overload Relay Selection) and
Pr,07.00(Motor Rated Current (Motor 0))
NOTE
Please refer to Pr06-06 Electronic Thermal Relay Selection for <motor cooling curve with
shaft-fixed fan diagram> and <motor cooling curve with independent fan diagram>.
