Cooling induction motors

Theory, performance and constructional features of induction motors 1/25 Table 1.12 Normal systems of cooling for totally enclosed large machines... 

Figure 14-2A. Alternating current (AC) induction motor cross-sectional view of 220/440V, 3-phase, 60-cycle, totally enclosed fan-cooled standard motor. (Used by permission Reliance Electric Co., Div. Rockwell Automation.)...

IEEE 841, Standard for petroleum and chemical industry— Severe duty totally enclosed fan-cooled (TEFC) squirrel cage induction motors — Up to and including 370 kW (500 hp). )... 

Induction motors are the most frequent in use because of their simple and rugged construction, and simple installation and control. They are constant speed devices available as 3600 (two-pole), 1800, 1200, and 900 rpm (eight-pole). Two speed models with special windings with 2 1 speed ratios are sometimes used with agitators, centrifugal pumps and compressors and fans for air coolers and cooling towers. Capacities up to 20,000 HP are made. With speed... 

Table 6.31 Comparison between e, d and non-explosion protected industrial purpose cage induction motors (4 poles, 50cps/totally enclosed/fan cooled) (by courtesy of Loher GmbH, Ruhstorf/Germany)...

Figure 6.91 Longitudinal section drawing of a flameproof cage induction motor, shaft and stator housing, water cooled, with pole changing.

Figure 6.92 Total view of a water-cooled flameproof cage induction motor for coal mines.

Figure 6.96 Double-rotor cage induction motor, flameproof, shaft and stator housing water cooled.

The rotor is driven by a planar induction motor whose armature plate is attached to the bottom end cap and whose stator is a flat winding with pole pieces outside the vacuum case. The motor is provided with cooling coils and a speed pickup. 

Tesla Motors Model S can accommodate seven people (five adults and two children) and is priced under 50,000. This particular model uses a three-phase, water-cooled, AC induction motor and has an operating range of more than 300 miles. The model has a top speed of 120 mph as well as some unique features, such as a 17-in. infotainment touch screen with 3G Internet coimectivity. 

The electric drive is a three-phase squirrel-cage induction motor with the stator and rotor sealed in thin stainless-steel cans which prevent the process fluid from coming in contact with the stator or rotor windings. The cans are supported by the laminations to contain the system pressure of 2000 psi. The motor is enclosed in a heavy pressure vessel which is designed to hold the full system pressure in the event of a can failure. The motor and bearings are cooled by the use of a small auxiliary impeller. 

It is necessary to consider the environment to choose the proper motor endosuie. Explosion-proof motors usually have a UL label certifying that they are suitable for the defined classified area. The UL label, however, is suitable only for 60 Hz sine-wave power. When an explosion-proof motor is operated on adjustable-frequency control power, the 60 Hz sine-wave UL label is voided. In addition, induction motors are normally rated for 40 C (104°F) ambient temperature. Use in a higher ambient temperature may require additional cooling or overframing. 

Motors shall be squirrel cage induction type with (totally enclosed, fan-cooled) (encapsulated) (splashproof) enclosure and roller-type bearings with NEMA Class A insulation. Motors shall be (single... 

Electric motors select synchronous for low speed usual application for either synchronous or induction 500 to 2100 rpm 150 to 500 kW. Usually use total enclosed Fan cooled (TEFC) enclosure, efficiency 84 to 95%. 

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