If the operating temperatures are significantly high and can vary between 120 ° C and 150 ° C, or if the rotational speeds are above 1,500 rpm, it is advisable to use mineral oil to perform proper lubrication. The oils have lubricating properties appropriate to the working conditions. On low power engines, initial lubrication in the assembly is provided in a way that ensures a high amount of operating hours. In some cases, the grease reserve may be sufficient for the entire life of the device. On large engines there is a need for external lubrication. The frequency of lubrication varies according to the design of the bearings and the specifications of the lubricants used.
Thus, it is important to be aware that at a temperature in the average of 40 ° C, the life of a continuously running ball bearing may be approximately three years or even longer. However, for every 10 ° C increase in working temperature the durability decreases by an average of 50%. Proper lubrication of the bearings, in addition to improving performance, can prevent temperature rise which reduces the durability of such equipment.
In summary, it can be stated that electric motors of alternating current have some important divisions, all of which are properly normalized and among the most common are the double polarity motor, in which it has the capacity to act in two speeds power output, double-spindle motor, with an output for each side. AC electric motors consist of rotating equipment that run from electrical power. The alternating current electric motor does not require any storage of the same in relation to the power supply and basically acts to rotate a second one.
This type of motor duty motors can be divided basically into two categories, one of the synchronous type and another, of the asynchronous type, and the asynchronous ones have sliding according to the load intensity and are the most found engines in the industries. Other categories among AC motors are three-phase and single-phase motors. The main difference between these two types of power is that it can change the versatility and performance of the motor, since the single phase motors are more limited and need starter capacitors, otherwise they are not capable of overcoming inertia.