Modern electrical motors are available in many different forms, such as single-phase motors, three-phase motors, brake motors, synchronous motors, asynchronous motors, specially customised motors, two-speed motors, three-speed motors, and so on, all with their own performance and characteristics.
Warning: The content of this article is cited from ABB Soft Starter Handbook!!!
For each type of motor, there are many different mounting arrangements, for example: foot mounting, flange mounting or combined foot and flange mounting.
The cooling method can also differ very much, from the simplest motor with free self-circulation of air to a more complex motor with totally enclosed air-water cooling with an interchangeable cassette type of cooler.
To ensure a long lifetime for the motor it is important to keep it with the correct degree of protection when under heavy-duty conditions in a server environment.
The two letters IP (International Protection) state the degree of protection followed by two digits, the first of which indicates the degree of protection against contact and penetration of solid objects, whereas the second states the motor’s degree of protection against water
The end of the motor is defined in the IEC-standard as follows:
The D-end is normally the drive end of the motor.
The N-end is normally the non-drive end of the motor.
Note that in this handbook we will focus on asynchronous motors only.
Squirrel cage motors
In this book, the focus has been placed on the squirrel cage motor, the most common type of motor on the market. It is relatively cheap and the maintenance cost is normally low.
There are many different manufacturers represented on the market, selling at various prices.
Not all motors have the same performance and quality as for example motors from ABB. High efficiency enables significant savings in energy costs during the motor’s normal endurance. The low level of noise is something else that is of interest today, as is the ability to withstand severe environments
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