Altistart 48 Enclosed Altistart 48 Soft Starters Page 10 Functions

10 Altistart 48 soft starters for asynchronous motors Protection Functions Functions (continued) Protection functions Calculated motor thermal protection The soft starter continuously calculates the temperature rise of the motor based on the nominal current and the actual current absorbed. In order to adapt the ATS48 soft starter to individual motors and applications, several protection classes are offered in accordance with standard IEC 60947-4-2: Class 30, Class 25, Class 20 (severe duty application), Class 15, Class 10 (standard duty application), Class 10 A, sub-class 2. Different protection classes are defined for the starting capacities of the motor Cold start without detected thermal fault (corresponding to a stabilized motor thermal state, motor switched off) Warm start without detected thermal fault (corresponding to a stabilized motor thermal state, at nominal power) The motor thermal protection function can be disabled. After the motor has stopped or the soft starter has been switched off, the thermal state is calculated even if the control circuit is not energized. The ATS48 soft starter's thermal control prevents the motor from restarting if the temperature rise is too high. If special motors are used which do not have thermal protection, provide external thermal protection via probes or thermal overload relays. The soft starter is factory preset to Class 10. The tripping curves to the left are based on the relationship between the starting current (Is) and the adjustable nominal motor current (In). Reset motor thermal state Activating this function resets the motor thermal state calculated by the ATS48 to zero. Motor thermal protection with PTC probes PTC probes are integrated into the soft starter, thus avoiding the necessity of an external thermal protection device. The "PTC probe thermal overshoot" fault opr alarm can be indicated using a configurable logic output or displayed via the serial link. This function can be disabled. Note: The PTC probe protection and calculated motor thermal protection functions are independent and can be active simultaneously. Soft starter thermal protection The soft starter is protected against thermal overloads by an analog thermal probe. The cooling fan on the soft starter is switched on as soon as the heatsink temperature reaches 122 F (50 C). It is switched off when the temperature returns to 104 F (40 C). 0.5 1 10 100 1000 10000 Time (sec) 8.00 Id/In 7.00 6.00 5.00 4.00 3.00 2.00 1.12 30 25 20 15 10 10A 2 Motor Protection Class: Motor thermal protection curves (cold) 0.5 1 10 100 1000 10000 8.00 7.00 6.00 5.00 4.00 3.00 2.00 1.12 30 25 20 15 10 10A 2 Time (sec) Id/In Motor Protection Class: Motor thermal protection curves (warm) Trip time (cold) Trip time for a standard duty application (class 10) Trip time for a severe duty application (class 20) Is = 3 In Is = 4 In Is = 5 In Is = 3.5 In Is = 4 In Is = 5 In 46 sec 23 sec 15 sec 63 sec 48 sec 29 sec Trip time (warm) Trip time for a standard duty application (class 10) Trip time for a severe duty application (class 20) Is = 3 In Is = 4 In Is = 5 In Is = 3.5 In Is = 4 In Is = 5 In 23 sec 12 sec 7.5 sec 32 sec 25 sec 15 sec

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