Speed reducers are used to control and vary the revolutions per minute (rpm) of electric motors, as in most industrial processes the motor speeds are too high. The use of speed reducers gives us a smaller number of output rpm, but without significantly decreasing power, safely and effectively increasing torque. As we described earlier, electric motors could be defined as the heart of the industry, if we base ourselves on this mention we can say that the speed reducers are those that regulate the rhythm and speed required in each production process.
The gearboxes are designed based on gears, circular and toothed mechanisms with special geometries according to their size and function in each motor. But basically, a speed reducer is a transmission system characterized because its output speed is lower than the input speed. Kelvin gear box is one of the safest bets on this department.
Choose the best speed reducer for each case
Frequency variators and chain and pulley systems are different alternatives to the use of speed reducers, although in cases where a speed of less than 900rpm is required, they are not very successful alternatives, since while converters involve high power and cost, chain or pulley systems are inefficient.
What are the main benefits of using speed reducers?
- They provide regularity both in speed and power transmission.
- They increase efficiency in the transmission of power supplied by the motor.
- They reduce maintenance costs by providing greater transmission safety.
Which elements should be taken into account when choosing a speed reducer?
- Motor information: Power, number of poles, frequency and supply voltage.
- Environment of the installation and degree of protection of the working environment, depending on humidity, temperature, dirt, corrosion…
- Speed in RPM input and output speed of reducer.
- Maximum/medium torque.
- Characteristics of the work to be performed:
- Duration of service hours/day.
- Start times per hour, reversing speed
- Type of load: uniform, with shock, continuous, discontinuous, among others.
- Type of coupling between the electric motor and gearbox: direct, coupling, belt, chain… Both the input and output shafts.
- Horizontal, vertical output shaft, etc.
The power factor
In practice, it is difficult for a reduction unit to perform its work under ideal conditions. Therefore, the power required by the driven machine must be multiplied by a Service Factor (Fs), which takes into account the specific characteristics of the work to be carried out and the result, called Selection Power (Ps), which is used to determine the size of the reducer in the selection tables. For special conditions such as high start-stop frequencies or inversions in motor running, high humidity or ambient temperature and special constructions or applications, it is advisable to take into account the service factor when terminating the power to be managed by the gearbox.
It is obvious that the cost factor is one of the most important factors when making a purchase decision, but it is advisable to check factors such as consumption, the need for maintenance and the reliability of the production process that will form part of the reducer we need, in order to optimize the selection of the reducer that best suits our application / project.