Siemens bt300 Operator's Manual page 78

Chapter 4 - Parameters and Menu Structure
Parameters (M3)
The torque values for setting the under-load curve are set in percentage which refers to the nominal torque of the
motor. The motor's name plate data, parameter motor nominal current and drives nominal current IL are used to
find the scaling ratio for the internal torque value. If other than a nominal motor is used with the drive, the accuracy
of the torque calculation decreases.
Under-load protection: Field weakening area load (P3.9.16)
The torque limit can be set between 10.0 and150.0% × T
This parameter gives the value for the minimum torque allowed when the output frequency is above the field
weakening point. See the following figure.
If you change Motor Nom Currnt (P3.1.1.4), this parameter is automatically restored to the default value.
Under-load protection: Time limit (P3.9.18)
This time can be set between 2.0 and 600.0 s.
This is the maximum time allowed for an under-load state to exist. An internal up/down counter counts the
accumulated under-load time. If the under-load counter value goes above this limit the protection will cause a trip
according to Underload Flt (P3.9.15). If the drive is stopped the under-load counter is reset to zero.
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Building Technologies
Figure 22: Setting of minimum load.
Siemens BT300 HVAC Drive
Motor.
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DPD01809
2016-06-07