Siemens S120 configurationmanual Short-time duty S2 and intermittent duty S3

Configuring the motor

5.3 Short-time duty S2 and intermittent duty S3

5.3Short-time duty S2 and intermittent duty S3

Short-time duty S2

In the case of short-time duty S2, the load time is so short that the final thermal state is not reached. The subsequent zero-current break is so long that the motor practically cools down completely.

CAUTION

An excessive load can lead to the destruction of the motor.

The load may not exceed the value IMAX specified in the data sheets!

The motor may only be operated for a limited time t < tMAX with a current IN < IM ≤ IMAX. The time tMAX can be calculated using the following logarithmic formula:

Y

W  W yOQ 

0$; 7+ Y

with ν = (IM / IN)2 and the thermal time constant tTH.

The thermal time constants, the maximum currents and the rated currents of the motors can be taken from the data sheets.

Note

The above equation applies with the prerequisite that the starting temperature of the motor is the same as the intake temperature of the water cooling system TVORL in accordance with the data sheet.

Example

Motor 1FW6190-xxx15-2Jxx is to be operated from a cold state at maximum current.

●IMAX = 47 A, IN = 26 A; this results in ν = 3.268

●tTH = 180 s

The motor can be operated for a maximum of 66 s at maximum current.

76	1FW6 Built-in torque motors
	Configuration Manual, 05/2009, 6SN1197-0AE00-0BP3