The IEC 38 “standard voltages” standard (sixth edition) was published in 1983. This standard describes the standard voltages for the network, the equipment and the installations. This standard makes provisions for a “standard voltage” of 3 x 230V/400V - 50 Hz. As a result of this standardization, a larger area in which the same voltage dominates will be created in due course. This ensures fewer voltage variations in devices.
More about tolerances
The network voltage tolerances during operation, have been defined in national standards such as NEN 3173, where a distinction is made between area A and area B.
A voltage tolerance of ± 5% applies to area A and of ±10% to area B. A machine must be able to fulfil its main function in area A, but does not completely has to display the properties such as related to the allocated voltage and allocated frequency and may, therefore, specifically display deviations. The temperature increases may be larger than with the allocated voltage and the allocated frequency.
A machine must be able to fulfil its main function in area B, but may display deviations with regard to properties such as with regard to the allocated voltage and the allocated frequency that are larger than in area A. Temperature increases may be larger than at the allocated voltage and the allocated frequency and will probably also be larger than the temperature increases in area A. Long-term operation at the outer limit of area B is not recommended.
Rotor nl® electric motors
The rotor nl electric motors are supplied in 3 x 400V—50Hz (Y or D). Other voltages can be supplied on request. The voltage for which the electric motor has been designed, is always specified on the rating plate of the specified electric motor.
1. 230V between a phase and zero and 400V between the phases themselves in a three-phase system.
2. This means that the allocated torque (Nm) of the electric motor remains safe guarded.
3. The limits for the temperature increases and the temperatures in accordance with the standard, refer to the state where the key data applies; they may be exceeded more than proportionally as the state during operation starts to deviate from the state where the key data applies . During duty at the outer limits of zone A, the temperature increases and the temperatures may rise approx. 10K than the limits for temperature increase and temperatures in accordance to the standard.
4. A machine will at some time be used outside the limits of area A with regard to applications and under practical operational conditions. Such situations must be limited with regard to their scope, duration and abundance. If possible, corrective measures must be taken within a reasonable time period, for example, by reducing the power. Such an intervention can prevent that the service life of the machine is shortened as a result of thermal ageing.