8
Operation
Line operation
Operating Instructions – Explosion-Protected MOVI-SWITCH
®
Drives
39
8.3
Line operation
8.3.1
Motors in category 3
Continuous duty
The motors are designed for continuous duty at a constant power rating (S1) and are
marked accordingly. This includes low load startup at a small number of starts per
hour that cause hardly any additional heating.
Overload protection must be ensured using a time delayed, current-controlled over-
load protection device.
Switching operation
In case of switching frequencies that are assigned to duty types S3, S4, and S6, the
load changes must be considered in addition to start-up. This is ensured by calculating
the permitted switching frequency.
To calculate the permitted cycles per hour, use the formula for calculating the switch-
ing frequency.
The evaluation of PTC thermistors (/TF) is the only measure to prevent overheating.
Important notes on
the brake
In line operation, the brake is applied at rated speed of the motor when the drive is
switched off or in case of an emergency stop. The braking work may not exceed the
permitted maximum braking work per braking operation. Observe the information in
the manual "Project Planning for BE.. Brakes – DR.., DRN.., DR2.., EDR.., EDRN.. AC
Motors – Standard Brake/Safety Brake".
The evaluation of a PTC thermistor (/TF) is the only measure to prevent overheating.
The brakemotors from SEW‑EURODRIVE are equipped with PTC thermistors (/TF).
25988670/EN – 04/2020
