Semiconductor soft starter 3RW3 Overload relay's cur- rent setting A factor is specified by which the rated current of the soft starter has to be reduced. Example: Compensation factor for the unit's rated current = 0.9 Chosen unit = 3RW3014-1CB14 (in normal circumstances, this unit has a rated current of 6 A at 40° C) Accordingly, the actual rated current of the unit is: 0.9 x 6A = 5.4 A Compensation factor forswitching frequency The switching frequency is the maximum permitted number of starts per hour. This value must be modified by the specified compensation factor.
The number of permitted starts per hour are listed in the table 8.7.1 control elec- tronics/power electronics in the chapter 8.7, Technical data. The specified compensation factors refer to the following operating condi- tions: S4 operation, 40° C ambient temperature, 30% duty cycle Example: Compensation factor for the switching frequency = 1.5 Chosen unit = 3RW3014-1CB14 (under the conditions specified above, this unit has a maximum switching frequency of 30 starts/hours) This results in a corrected switching frequency of:: 1.5 x 30 = 45 starts/hour A larger unit can also be used to increase the switching frequency.
Compensation factor for the circuit-breaker's current setting When the soft starter 3RW30 and the circuit-breaker 3RV1 are combined, there may be a need to correct the circuit-breaker's setting. The compensa- tion factor specifies the amount of the change. Example: Compensation factor for the circuit-breaker's current setting: 1.1 Chosen unit = 3RW3014-1CB14 The connected motor has a rated current of 5 A.. The circuit-breaker's setting must be changed to:
1.1 x 5 A = 5.5 A Compensation factor for the overload relay's current setting When the soft starter 3RW30 and a thermal overload relay 3RU1 or a soft starter 3RW30 and an electronic overload relay 3RB10 are combined, the overload relay's setting must be corrected accordingly. The compensation factor specifies the amount of the change. Example: Compensation factor for the overload relay's current setting: 0.9 Chosen unit = 3RW3014-1CB14 The connected motor has a rated current of 5 A The overload relay's setting must not be changed to 0.9 x 5 A = 4.5 A Rev. 08/99 8-19