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Entry type: FAQ Entry ID: 33387921, Entry date: 12/15/2008
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Operating modes of motors

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QUESTION:

 

 

 

 

 

What motor operating modes are there?


ANSWER / REMEDY / NOTES:

  

 

 

  

 

The operating mode describes the loading of the machine according to size, duration and chronological sequence, including start-up, electrical braking, no-load operation and being at rest.

 

 

 

 

 

DIN VDE 0530 distinguishes between ten operating modes (S1 to S10).

 

 

 

 

 

 

 

Selected operating modes, a) continuous duty (S1),

b) short-time duty (S2),  c) intermittent duty without influence of the start-up process (S3)

   

 

 

 

S1 operating mode (continuous duty)

Operation with constant loading of unlimited duration during which the thermal steady state of the motor is reached.

 

 

 

 

 

S2 operating mode, short-time duty

Operation with constant loading without the thermal steady state being reached and with a subsequent pause during which the motor temperature drops to the temperature of the cooling medium.

 

 

 

 

 

S3 operating mode, periodic intermittent duty

A sequence of identical cycles without a thermal steady state being reached. Each cycle is composed of a time with constant loading and a pause. The starting current has practically no effect on the increase in temperature. The cycle must last 10 min and the relative cyclic duration factor must have one of the following values:

15%, 25%, 40%, 60%.

 

 

 

 

 

S4 operating mode, periodic intermittent duty with influence of the start-up process

A sequence of identical cycles without a thermal steady state being reached. Each cycle is composed of a noticeable starting time, a time with constant loading and a pause. The cycle must last 10 min and the relative cyclic duration factor must have one of the following values:

15%, 25%, 40%, 60%.

 

 

 

 

 

S5 operating mode, periodic intermittent duty with electrical braking

A sequence of identical cycles without a thermal steady state being reached.

Each cycle is composed of a noticeable starting time, a time with constant loading, a time of rapid electrical braking and a pause. The cycle must last 10 min and the relative cyclic duration factor must have one of the following values:

15%, 25%, 40%, 60%.

 

 

 

 

 

S6 operating mode, uninterrupted periodic duty

A sequence of identical cycles without a thermal steady state being reached. Each cycle is composed of a starting time, a time with constant loading and a no-load operating time. There is no pause. The cycle must last 10 min and the relative cyclic duration factor must have one of the following values:

15%, 25%, 40%, 60%.

 

 

 

 

 

S7 operating mode, uninterrupted periodic duty with electrical braking

A sequence of identical cycles without a thermal steady state being reached. Each cycle is composed of a starting time, a time with constant loading and a time with electrical braking. There is no pause. The cycle must last 10 min.

 

 

 

 

 

S8 operating mode, uninterrupted periodic duty with load/speed changes

A sequence of identical cycles without a thermal steady state being reached. Each cycle is composed of a time with constant loading and a particular speed and one ore more times with other loadings at different speeds. There is no pause. The cycle must last 10 min and the relative cyclic duration factor must have one of the following values:

15%, 25%, 40%, 60%.

 

 

 

 

 

S9 operating mode, non-periodic duty with load/speed changes

Loading and speed change non-periodically within the permissible operating range. Overloading which can be far above full load can often occur.

(Example: wind-energy generators)

 

 

 

 

 

S10 operating mode, duty with discrete constant loads

Operating mode that does not include more than four particular load values, wherein no-load operation and being at rest can be included. A thermal steady state is reached under each of the loads (even no-load operation and being at rest). The maximum loading must not exceed 1.2 times the S1 loading.

     

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