the mechanical variable speed drives offer certain advantages as well as disadvantages depending on your motor application.  While all variable frequency drives (VFDs) control the speed of an ac gearmotor by varying the motor's supplied voltage and frequency of power, they all do not use the same designs in doing so. it's highly reliable, affordable and reflects the least amount of harmonics back into its power source.

Externally, the mechanical variable speed drive consists of a rugged, sealed cast case, an input shaft, output shaft and adjustable speed control. Two models are equipped with a reversing lever that permits clockwise, neutral and counter-clockwise operation. inline gearbox speed adjustments are easily made by moving a lever control through an arc or turning the hand-wheel of a screw type control. In either case, easy and precise speed control settings are possible with Zero-Max adjustable speed drives - also referred to interchangeably as variable speed drives.

The regenerative braking function is of great importance to the mechanical variable speed drives, which can effectively improve the efficiency of the system and realize the energy-saving purpose. Through the analysis and discussion of various regenerative circuits of variable speed drives, this paper provides a reference for practical application selection. The regenerative circuit based on the energy storage device and the common dc bus is suitable for certain applications. Based on the regeneration of the power electronic converter circuit, the current use very much, which USES the regeneration of the thyristor circuit, low cost, easy to achieve high power level, but because of thyristor is half controlled device, must consider the problem of the commutation of the need to take measures to ensure the reliable commutation, they inject a certain amount of harmonic current to the grid at the same time; Regeneration circuit type based on full controlled devices, although the cost is relatively high, but performance is good, can easily realize two-way flow of energy, and can significantly improve the power quality of grid side, therefore has good application prospect. Three - level dual PWM converter is also an optimal scheme for the application of regenerative circuits in multi-level topologies.

   There are many kinds of machines. Their appearance, structure and use are different, have their individuality, also have their commonness. We will machine after serious research and analysis, it can be seen that some machines are other forms of energy can be transformed into mechanical energy, such as motor, gasoline engine, steam turbine, this kind of machine is called the prime mover; Some machines need to be driven by an original motive, such as a lathe, a thresher, and a pump. These machines are called workmachines. The movement from the original motive to the working machine, the movement from the part of the machine to that part of the machine is called the transmission. There are many ways of driving, mechanical transmission, hydraulic, pneumatic, and electrical transmission.

Bucket elevator drives main transmission and auxiliary transmission are of integrated design, the structure is compact.Main and auxiliary driving can be automatically switched with electric control.Remote control doesn't need extra manual operation, which is convenient for installation and debugging of users.