Although the inertia is not a problem for the electric motor with soft starting, it is yes for the drive with frequency inverter. Centrifugal applications require the motor and drive to be sized for the maximum operating speed conditions. Alternative loads shall be sized for minimum operating speed conditions.
From any point of view, actual load data must be provided to all electric motor manufacturers in order to ensure that the motor will be able to start and accelerate the load and work within the specified temperature limits and under all conditions of operation. c1f1c0les hps fortress In most variable speed applications, the maximum operating speed is or is close to the nominal speed of a standard motor, which is directly connected to the mains. Low-speed operations do not share the same mechanical integrity problems as high-speed operations, but they certainly share the problems of bearings, lubrication and cooling. The minimum operating speed must be mentioned in the Data Sheet or Specification, since the engine cooling system is connected closely to its rotation.
The armature winding is made by copper conductors insulated from each other and mounted in the grooves of the rotor and the torque at start of this type of motor is much better than the previous one because we can put resistors in series with the winding phases of the rotor. There are types in which the resistors are mounted on the rotor and eliminated, when the machine reaches its normal speed, through centrifugal mechanisms. In some types of motors, so that the brushes do not run out during normal running, they are suspended and the rings are short circuited by means of levers.
With the addition of rheostats in addition to improving the motor torque, we can vary the speed of the motor, but with the drawback of increasing the Joule loss in the resistors, alemite with best prices reducing their efficiency. Another type of coiled rotor is one in which its windings are attached to the collector rings on which the brushes rest. For these types we use rheostats, in star (Υ), connected in series with the windings of the rotor through brushes and collector rings. As the motor adds its speed, the rheostat is operated in order to gradually remove the resistors from the circuit until the star windings are connected.