Water cooling flameproof

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

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

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

Rated voltage 1000 V Max. motor rated power 511 kW Cooling water cooled Dimensions Height x width x depth 1000 x 2860 x 800 mm3 Added volume of flameproof compartments 1.5 m3 Weight (total) 3700 kg Type of protection EEx de I. (b) Frequency convertor according to Fig. 6.104(a), doors of flameproof compartments opened. 

Where a.c. supplies exist, transformer-rectifiers are the most economical source of d.c. for cathodic protection systems. In the case of pipelines, standard transformer-rectifiers, either oil or air cooled, can be employed. They range in size from 5A, 5V for small systems to 100 A, 48 V for major pipeline schemes. A typical output for a well-coated cross-country pipeline in the UK would be 5 A, 48 V. In the case of sea-water jetties where the voltage required is usually low because of the lower sea-water resistivity, a typical rectifier size for a major installation would be 500 A, 18 V. For offshore pipelines and loading platforms where a fire hazard exists, it is usual to employ certified flameproof or intrinsically safe rectifiers to overcome any possibility of fire hazard should faults develop in the unit. 

Following the philosophy of explosion protection, the piping for cooling water shall be considered as empty and, as a part of the environment, filled with the gas-air mixture according to the grouping of the motor. (This is the practice when type testing such a motor for flameproofness.)... 

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