Lenze i550

Speed compensaon for protecng motors at low speed
The inverter has been implemented with a compensaon funcon for low speeds. If the
motor is operated with frequencies below 40 Hz, the speed compensaon in 0x2D4B:002
(P308.02) must be set to "On [0]" (default). This seng ensures that the trigger me for the
monitoring is reduced at low speeds in order to account for the reduced self-cooling of AC
motors.
The speed compensaon for UL-compliant operaon must also be set to "On
[0]" in 0x2D4B:002 (P308.02).
If the speed compensaon is acvated, the release me is reduced as follows:
•
With an output frequency < 40 Hz: Reduced release me to 62.5 % + 37.5 % * output fre-
quency [Hz] / 40 [Hz]
•
With an output frequency ≥ 40 Hz: No reduced release me
The following diagram shows the reduced release me with acvated speed compensaon.
•
Maximum ulisaon 0x2D4B:001 (P308.01) = 150 %
•
Speed compensaon 0x2D4B:002 (P308.02) = "On [0]"
10
20
30
40
50
70
60
[s]
0
[Hz]
4 6 8
10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40
2
Output frequency
Release time
40 Hz
60 s
30 Hz
≈ 41 s
20 Hz
≈ 31 s
10 Hz
≈ 23 s
Frequency
Release time
The following diagram shows the possible permanent load with acvated speed compensa-
on without the monitoring being triggered.
•
Maximum ulisaon 0x2D4B:001 (P308.01) = 150 %
•
Speed compensaon 0x2D4B:002 (P308.02) = "On [0]"
20
40
60
80
120
100
[%]
0
[Hz]
4 6 8
10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40
2 0
Output frequency
Possible permanent load
40 Hz
110 %
30 Hz
99 %
20 Hz
90 %
10 Hz
79 %
Frequency
Load
In case of 0 Hz, only a load of 62.7 % (≈ 62.5 %) with regard to the load at 40 Hz or above is
possible (69 / 110 * 100 % = 62.7 %). In case of a deviang seng in 0x2D4B:001 (P308.01),
the maximum possible motor load changes proporonately.
Parameter
Address Name / seng range / [default seng] Info
0x2D4B:001
(P308.01)
Motor overload monitoring (i²*t): Maximum ulisa-
on [60 s]
(Motor overload: Max.load.for 60s)
30 ... [150] ... 200 %
Maximum permissible thermal motor ulisaon (max. permissible motor
current for 60 seconds).
•
100 % ≡ rated motor current 0x6075 (P323.00)
•
If the motor is actuated with the current set here for 60 seconds, the
maximum permissible thermal motor ulisaon is reached and the
response set in 0x2D4B:003 (P308.03) is executed.
•
If the motor is actuated with a dierent current, the me period unl
the motor overload monitoring funcon is acvated is dierent. Gen-
erally the following applies: the lower the current, the lower the ther-
mal ulisaon and the later the monitoring funcon is triggered.
Conguring the motor control
Motor protecon
Motor overload monitoring (i²*t)
232