IEC 60 034-1:



*S1 : C**tinuous running duty.The motor works at a c**stant load for enough time to reach temperature equilibrium.
S2 : Short-time duty.
Operati** at c**stant load for durati**s of 10, 30, 60 and 90 min are recommended. After each operating period, the motor has to be de-energised for a sufficient durati** until the windings are cooled to ambient temperature.
S3 : Intermittent periodic duty.
The starting current does not significantly affect the temperature rise.
Duty cycle is 10 min unless otherwise agreed.
Cyclic durati** factor of 15%, 25%, 40% and 60% may be c**sidered.
S4 : Intermittent periodic Duty with starting.
Starting has influence ** temperature rise of windings.
Starting load-torque (N), number of starts per hour, cyclic durati** factor and factor of inertia (Fl) have to be given.
S5 : Intermittent periodic duty with electric braking.
Starting and brakings have influence ** temperature rise of windings.
Starting load-torque (N), number of starts per hour, cyclic durati** factor and factor of inertia (Fl) have to be given.
S6 : C**tinuous-operati** periodic duty.
There is no temperature rise when the motor is loaded at its rated output.
Duty cycle is 10 min unless otherwise agreed.
Cyclic durati** factor of 15%, 25%, 40% and 60% may be c**sidered.
S7 : C**tinuous-operati** periodic duty with electric braking.
Brakings have influence ** temperature rise of windings.
Load and factor of inertia (Fl) at the operating period have to be given.
S8 : C**tinuous-operati** periodic duty with related load/speed changes.
Brakings have influence ** temperature rise of windings.
Load, cyclic durati** factor and factor of inertia (Fl) for each speed at the operating period have to be given.
S9 : Duty with n**-periodic load and speed variati**s.
Brakings have influence ** temperature rise of windings.
Load and factor of inertia (Fl) for each speed have to be given.

Cyclic durati** factor is the ratio of the period of loading, including starting and electrical braking, to the durati** of the duty cycle and is expressed as a percentage.


Factor of inertia (Fl) = JM =Jz
JM


JM : Moment of inertia of the motor (kgm2)
Jz Total moment of inertia of driven machine and parts as couplings etc... referred to motor shaft (kgm2)

The nature of braking, whether mechanical or electrical (D.C. or reversed current) has also to be stated.
The ratings and performance data given in this catalogue,are for c**tinuous running at c**stant load for a sufficient durati** to reach thermal equilibrium which corresp**d to duty type SI.
However, standard range motors may be operated at all the other duty types, provided that the limit of permissible temperature rise is not exceeded.