Special motor winding

Selection of special motor windings

In the case of continuous applications and applications operated with fixed speeds such as agitators, conveyor belt, pumps and similar, for example, a drive solution that is as energy efficient as possible should be selected to keep the power losses and the module outlay as low as possible.
Depending on the external mechanically power required
Pmech = Md * n * / 30 - ( e.g. 0.15 Nm * 300 rpm * / 30 = 4.5W )
, an equivalent electrical power is required for this with
Pel = I² * R or U * I ( 0.5² A * 19 Ohm = 4.5 W (= ST4118M0706).

All Nanotec stepper motors and BLDC motors have been measured on a calibrated torque test stand in regard to torque versus speed and illustrated in the catalog as well as on the web. The customer can then obtain the requested data relatively easily from the torque characteristics or calculate them with the motor assistant. In the example shown above, the motor size ST4118M0906 ( = 0.64² * 11.4 = 0.57W) would fulfill the requested power with a safety of approx. 20% while the ST4118M0706 would work at the requested power limit. Nanotec offers different windings with the same construction length in order to provide the customer with as good an energy compromise as possible for his starting speed. In the example given above, for example, the ST4118M0408 would probably draw the least current and, hence, dissipate the lowest power with 24 V * 0.28 A = 6.7 W (via PWM control, very roughly approx. 3.4 W) where the winding with 60 Ohm would not provide the requested power due to the Md characteristics. By contrast, the ST4118M1206 motor with the same construction volume, a resistance of 6.2 Ohm and a current of 0.85 A dissipates 24 V*0.85 A = 20 W (average value approx. 10 W) so that the power dissipation compared to the ST4118M0904 with 24 V*0.64 = 15.2 W (average value approx. 7.6 W) is approx. 30% higher.

To generate the lowest power dissipation in the respective application, in addition to the windings listed in the catalog Nanotec offers another series of customer-specific windings to its customers. This flexible winding construction ensures that the customer can always realize the nowadays more important objective of energy savings in its new devices. In addition to lower power dissipation, the temperature increase is lower, hence the expected service life is higher and the electronic components of the control can be kept smaller as well.

High-temperature winding

In some customer-specific motors of the ST4118.. and ST5918… series high-temperature windings, winding formers and paint coatings with the insulation class F = 155°C have already been constructed. By contrast, further material tests are required in insulation class H = 180 °C, primarily with regard to winding formers. Compared to standard motors, the torque in high-temperature motors drops by approx. 5-10%. Higher temperatures can generally be reached with shorter power-up time or motors with larger construction type which also generate proportionally lower inherent temperature rises with lower nominal current and, hence, can be deployed for higher ambient temperatures. High temperature windings are sometimes also used in vacuum motors.