Motor Overload Summary; Automatic Switching Frequency Reduction - ABB EC Titanium Series Manual

12.7 Motor Overload Summary

The EC Titanium Drive features both hardware and software protection of the output stage to prevent damage. In addition,
an I x t system is used to monitor motor overload condition and prevent damage to the motor due to operation for prolonged
periods at high load. I x t protection is software based, using the value for motor rated current programmed in 9906. An
internal accumulator register is used to estimate the point at which damage may occur to the motor, and operates as
follows:
Motor Current < 9908
Motor Current = 100% P-08
Motor Current > 100% P-08 < 150% P-08
Motor Current > 150% P-08
Peak over current trip levels are shown in the table below.
Drive Rated Frame
Supply Voltage Size
100 – 115 VAC 1
110 – 240 VAC 1
200 – 240 VAC 1
380 – 480 VAC 1
380 – 480 VAC 2

12.8 Automatic Switching Frequency Reduction

The switching frequency selected in 2606 will be automatically reduced based on the heatsink temperature. In addition,
switching frequency is reduced under the following conditions:
Output Frequency based Effective Switching Frequency Reduction
At low output frequency, Effective Switching Frequency is automatically reduced. Hysteresis is applied to prevent continuous
switching. The operation is according to the following table:
2606
Effective Switching Frequency increases
when Output Frequency exceeds
Effective Switching Frequency reduces
when Output Frequency reduces below
Output Current Based Effective Switching Frequency Reduction
Effective Switching Frequency is automatically reduced based on motor load current as follows:
If 2606 = 12kHz, 16 kHz, 24 kHz, Effective switching frequency is reduced to 8 kHz when motor current exceeds 10.45A
(110% of the drive rated current). Switching frequency will return to the value set in 2606 when motor current reduces below
7.6A (80% of drive rated current)
If 2606 = 32kHz, Effective switching frequency is reduced to 8 kHz when motor current exceeds 10.45A (110% of drive
rated current). Switching frequency changes to 24 kHz when motor current reduces below 7.6A (80% of drive rated current).
Switching frequency will return to the value set in 2606 when motor current reduces below 6.7A (70% of drive rated current)
MN448
The accumulator value reduces towards zero. The time
required depends on the actual load current as explained
further below.
The accumulator value increases at a rate proportional to
the overload level, e.g. (Motor Current / Rated current) –
100%. If the overload limit is reached, the drive will trip,
displaying it.trp. to protect the motor.
For high current levels, the accumulator operates 16 times
faster than for current levels below 150% of 9906.
DC Bus Voltage Level (Volts DC)
Brake
Drive Type
Chopper
On
Voltage Doubler N/A
PFC N/A
All N/A
All N/A
All 780
32kHz
9.0Hz
7.0Hz
Brake Under
Chopper Voltage
Off Trip
N/A 160
N/A 160
N/A 160
N/A 320
756 320
24kHz 16kHz 12kHz
7.0Hz 5.0Hz 3.0Hz
5.0Hz 3.0Hz 1.0Hz
Minimum Over
Operating Voltage
(Inrush Trip
Disabled)
239 418
239 418
239 418
478 835
478 835
8kHz 4kHz
N/A N/A
N/A N/A
Technical Data 12-3