ParametersM-Max Series Adjustable Frequency Drive MN04020003E—October 2013 www.eaton.com 91Protective Functions, continuedPNU IDAccessRUN Value/Range DescriptionFactory Setting(P1.3)P8.4 709 X — Stall protection 1The stall protection function is an overload protection.It protects the motor from brief overloads (for example, blockedmotor shaft). The stall current is equal to the motor ratedoperational current x 1.3, stall time is 15 seconds, and stallfrequency limit is 25 Hz. If the current is higher than the limitand the frequency is less than 25 Hz, the drive will react asdefined by this parameterNote: With long motor cable lengths and low motor power(poor efficiency cos ), a higher (capacitive) motor current canflow causing early tripping. Solution: Motor reactor or sinus filter0 Deactivated1 Alarm (AL 15)2 Fault (F… 15), stop function according to P6.8P8.5 713 X — Underload protection 0The underload protection monitors the load of the connectedmotor in the range of 5 Hz up to the maximum outputfrequency. This requires that the output current of thefrequency inverter be monitored. A message will be generatedif the values set in P8.12 and P8.13 are undershot within20 seconds0 Deactivated1 Alarm (AL 17)2 Fault (F…17), stop function according to P6.8P8.6 704 X — Motor, temperature protection 2The motor temperature protection is designed to protect themotor from overheating. It is based on a temperature algorithmand uses the motor current (P7.1) to determine the motor load(see figure on Page 92)0 Deactivated1 Alarm (AL 16)2 Fault (F… 16), stop function according to P6.8P8.7 705 X — Motor, ambient temperature 40–20° to 100°C —P8.8 706 X — Motor, cooling factor at zero frequency 40.00.0–150% The cooling factor of the motor with a zero frequency definesthe relationship to the cooling of the motor at the ratedfrequency with the rated operational current without an externalfan (see figure on Page 92)P8.9 707 X — Motor, thermal time constant 451–200 min The temperature time constant determines the time-span inwhich the heat calculation model achieves 63% of its end value.It depends on the design of the motor and is different frommanufacturer to manufacturer. The larger the motor design,the greater the time constant
