Each option is applicable to various solutions, and depends on the capacity of power supply, and on a number of opportunities arising from applying an appropriate drive. If the speed control range will not fall below 10% of the face, it fits almost any frequency converter, but if you want to slow down and continue to provide with the rated torque on the shaft, you need to ensure the ability of the frequency converter to provide the engine at frequencies close to zero. In addition, with a range of speed control is associated another question that needs to be addressed, – cooling the engine. Typically, induction motor (with a self venting) cooling fan attached to its shaft, so reducing the rate of cooling efficiency drops sharply. Some inverters are equipped with the function of monitoring the thermal regime with the help of feedback through a temperature sensor mounted on the engine itself.
There are other options to address this issue, but without the use of the frequency converter. Mode Coasting (inertial braking), similar to engine shut-off from the mains, while the process may take some time. Especially if it's high inertial mechanisms. With the frequency converter can be made stopping or deceleration of the motor with the transition to a lower speed in a shorter period of time. Perhaps several options: – to give the network electricity (regenerative braking mode) – do stop serving stator voltage at a lower frequency or dc voltage, then the excess stored kinetic energy to stand out in the form of heat through the radiators of the frequency converter and motor (braking mode DC) – run a stop or braking with brake chopper and a set of brake application of a method is considered primarily in terms of economic benefits.