9300 servo plc, System blocks, 4 oc6/oc8 − i – Lenze DDS Target 9300 Servo PLC V8.x User Manual
Page 82
2.12
MCTRL_MotorControl (node number 131)
9300 Servo PLC
System blocks
2−76
L
9300 Servo PLC EN 5.1
2.12.17.4
OC6/OC8 − I
2
x t overload monitoring (current load of motor)
Note!
·
I
2
x t monitoring is based on a mathematical model which calculates a thermal motor load
from the detected motor currents.
·
The calculated motor load is saved when the mains is switched.
·
The calculated motor load is saved when the mains is switched.The function is UL−certified,
i.e. no additional protective measures are required for the motor in UL−approved systems.
·
However, I
2
x t monitoring is no full motor protection as other influences on the motor load
could not be detected as for instance changed cooling conditions (e.g. interrupted or too
warm cooling air flow).
Die I
2
x t load of the motor is displayed in C0066.
The thermal loading capacity of the motor is expressed by the thermal motor time constant
(
t, C0128). Find the value in the rated motor data or contact the manufacturer of the motor.
The I
2
x t monitoring has been designed such that it will be activated after 179 s in the event of a motor
with a thermal motor time constant of 5 minutes (Lenze setting C0128), a motor current of 1.5 x I
N
and a trigger threshold of 100 %.
Two adjustable trigger thresholds provide for different responses.
·
Adjustable response OC8 (TRIP, warning, off).
– The trigger threshold is set in C0127.
– The response is set in C0606.
– The response OC8, for instance, can be used for an advance warning.
·
Fixed response OC6−TRIP.
– The trigger threshold is set in C0120.
Behaviour of the I
2
x t monitoring
Condition
The I
2
x t monitoring is deactivated.
C0066 is set = 0 % and
MCTRL−LOAD−I2XT is set = 0.00 %.
When C0120 = 0 % and C0127 = 0 %, set controller inhibit.
I
2
x t monitoring is stopped.
The current value in C0066 and at the MCTRL−LOAD−I2XT output is
frozen.
When C0120 = 0 % and C0127 = 0 %, set controller enable.
I
2
x t monitoring is deactivated.
The motor load is displayed in C0066.
Set C0606 = 3 (off) and C0127 > 0 %.
Note!
An error message OC6 or OC8 can only be reset if the I
2
x t load falls below the set trigger threshold
by 5 %.