27 Electric Motors At low speed the ratio must be adjusted to compensate for the ohmic losses. Further forced cooling may be required in this speed range. 1.3.6 Motor Nameplate and Star or Delta Confi guration Normally the motor has a nameplate on it which has all essential motor data. Additional data are available in the motor catalogue or can be obtained from the manufacturer. IEC 60034-6 RPM Fig. 1.19 Motor nameplate shows essential data The nameplate shown has the following information: 1. It is a three-phase AC motor with a rated frequency of 50 Hz 2. Rated output (shaft) power is 15 kW 3.
The stator windings can be connected in series (star) with a rated voltage of 400 V and rated (apparent) current of 27.5 A 4. Alternatively, the stator windings can be connected in parallel (delta) with a rated voltage of 230 V and rated (apparent) current of 48.7 A 5. It has an IP 54 protection 6. Insulation class F (155 °C) and a power factor (cos. φ) of 0.90. 7. Rated speed 2910 RPM (a two-pole motor) is the motor speed at the rated voltage, rated frequency and rated load 8. Fulfi ls the IEC 60034-6 standards Some motor data (torque, effi ciency, etc.) can be calculated using the nameplate data.
For example the power factor can be used to calculate the active and reactive components of the motor current.