Normal operation
Measure the normal operating temperature T
operation
 at the installation site in °C. Set the values 
for shutdown and warning according to the operating temperature T
operation
. The set values 
depend on the design of the insulation system or the temperature class of the machine. The 
data can be found on the rating plate.
Table 7-4 Set values for monitoring the winding temperatures in normal operation 
Set value Insulation class 155(F) Insulation class 180(H)
Warning T
op
 + 10 K ≤ 145 °C T
op
 + 10 K ≤ 170 °C
Shutdown T
op
 + 15 K ≤ 155 °C T
op
 + 15 K ≤ 180 °C
7.6 Test run
After installation or inspection, carry out a test run: 
1. Start up the machine without a load. To do this, close the circuit breaker and do not switch 
off prematurely. Check whether it is running smoothly.  
Switching the machine off again while it is starting up and still running at slow speed should 
be kept to a bare minimum, for example for checking the direction of rotation or for checking 
in general. 
Allow the machine to run down before switching it on again.
2. If the machine is running smoothly and evenly, switch on the cooling equipment. Continue 
to observe the machine for a while in no-load operation. 
3. If it runs perfectly, connect a load.
NOTICE
Thermal overload of motors connected directly to the line supply 
In addition to the load torque, the ramp-up (accelerating) time is essentially influenced by 
the moment of inertia to be accelerated. While ramping up when connected to the line 
supply, the inrush (starting) current is a multiple of the rated current. This can result in 
thermal overload. This can damage the motor.
As a consequence, when ramping up, observe the following:
● Monitor the ramp-up time and number of consecutive starts. 
● Comply with the limit values and/or ramp-up conditions specified in the catalog or the 
order documentation. 
Start-up
7.6 Test run
SIMOTICS TN Series N-compact  1LA8
Operating Instructions 05/2016 85