Preparing for use 
  4.10 Voltage and frequency fluctuations during line operation 
1LA5/6/7/9, 1LG4/6, 1MA6/7, 1MB..1/2/3/4/5 - SH 63 ... 355 
Operating Instructions, 06/2018, A5E44455710A 
45 
 
Voltage and frequency fluctuations during line operation 
Unless stated otherwise on the rating plate, the permissible voltage/frequency fluctuation is 
corresponds to range B in IEC / EN 60034-1. 
Material damage due to excessively high winding temperature rise 
Do not exceed the winding temperature tolerances. Inadmissibly high winding temperatures 
can damage the machine over the long term. 
Keep within the permissible tolerance for voltage and frequency. 
Every machine must be protected against an inadmissible temperature rise. Observe the 
following notes: 
●  Protect every machine according to IEC/EN 60079–14 using a current-dependent, 
delayed circuit breaker with phase failure protection according to IEC/EN 60947 or a 
similar device in all phases. 
●  Set the protective device to the rated current (value is stamped on the rating plate). 
●  Protect the windings in a delta connection in such a way that the tripping unit or relay is 
connected in series with the winding phases. When selecting and setting the tripping unit, 
define the rated value of the phase current. The phase current is 0.58 times the rated 
machine current. Any thermal machine protection via direct temperature monitoring to be 
used in addition to the machine circuit breaker is specified on the rating plate if required. 
Thermal protection (Page 43) 
 
Rotational speed limit values 
Danger as a result of resonance within certain speed ranges 
At over-critical speeds, machines encounter resonance within certain speed ranges. Such 
vibrations can reach impermissibly high levels. This can result in death, serious injury or 
material damage.  
●  The controller must ensure that those speed ranges are blocked when the converter is in 
operation. Please note the data on the blocked speed ranges specified in the Electrical 
Data. 
●  The blocked speed ranges must be run through rapidly.  
Machine damage due to excessively high speeds 
Excessive rotational speed can lead to serious damage to the machine. This can result in 
death, serious injury or material damage.  
●  Avoid operation above the permissible speed by using the appropriate control function. 
●  Observe the speeds stamped on the rating plate and in the Electrical Data.