Activate The Atex Etr Monitor Function; Maximum Current Limit; Minimum Motor Frequency - Danfoss VLT PTC Thermistor Card MCB 112 Operating Manual

VLT® PTC Thermistor Card MCB 112
Operating Guide
Parameter
Parameter 1-99 ATEX ETR interpol points current
Parameter 1-23 Motor Frequency
Parameter 4-19 Max Output Frequency
Parameter 4-18 Current Limit
Parameter 5-15 Terminal 33 Digital Input
Parameter 5-19 Terminal 37 Safe Stop
Parameter 14-01 Switching Frequency
Parameter 14-26 Trip Delay at Inverter Fault

4.4.2 Activate the ATEX ETR Monitor Function

Procedure
1. Set parameter 1-90 Motor Thermal Protection to [20] ATEX ETR.

This activation of the ATEX ETR monitor function enables parameter 1-94 ATEX ETR cur.lim. speed reduction, parame-
ter 1-98 ATEX ETR interpol. points freq., and parameter 1-99 ATEX ETR interpol points current. Furthermore, it limits
parameter 4-18 Current Limit to 150%.

4.4.3 Maximum Current Limit

Operation above the thermal characteristic curve is allowed for a limited period of 60 s.
The actual thermal overload is based on the ETR function selected in parameter 1-90 Motor Thermal Protection and is shown in pa-
rameter 16-18 Motor Thermal.
Running above the characteristic curve for more than 50 s issues warning 163, ATEX ETR cur.lim.warning. Configure the reaction for
operating in Ex eb and Ex ec current limits in parameter 1-94 ATEX ETR cur.lim. speed reduction.
• 0%: The drive does not change anything besides issuing warning 163, ATEX ETR cur.lim.warning.
• >0%: The drive issues warning 163, ATEX ETR cur.lim.warning and reduces motor speed following ramp 2 (paramter group 3-5*
Ramp 2).
Example
• Actual reference = 200 RPM
•
Parameter 1-94 ATEX ETR cur.lim. speed reduction = 20%
• Resulting reference = 160 RPM
Operating above the characteristic curve for more than 60 s within a period of 600 s issues alarm 164, ATEX ETR cur.lim., and the drive
trips.
Operation above 150% nominal motor current trips the drive after 1 s with alarm 164, ATEX ETR cur.lim.
Operation above 180% nominal motor current immediately trips the drive with alarm 164, ATEX ETR cur.lim.
st
After the 1 power-up, the overload counter starts at a value that prevents resetting the thermal load value by power cycling. After
start-up, the overload warning is suppressed until the motor current exceeds the rated current for the first time.

4.4.4 Minimum Motor Frequency

The operation below the minimum frequency in parameter 1-98 ATEX ETR interpol. points freq. is allowed for a limited time only.
Running below the minimum frequency for more than 50 s issues warning 165, ATEX ETR freq.lim.warning.
Operation below the minimum frequency for more than 60 s within a period of 600 s issues alarm 166, ATEX ETR freq.lim.alarm. The
drive trips.
Danfoss A/S © 2022.08
Setting
Motor nameplate
Motor nameplate
Motor nameplate, possible reduced for long motor cables, sine-wave filter, or
reduced supply voltage.
Forced to 150% by parameter 1-90 Motor Thermal Protection [20] ATEX ETR.
[80] PTC Card 1
[4] PTC 1 Alarm
Check that the default value fulfills the requirement from the motor name-
plate. If not, use a sine-wave filter.
0
Commissioning
AQ267038105120en-000101 / 130R0104 | 21