Frequency convertor pressurized

In the following, a fully pneumatically operated control and monitoring unit as a safety device is described for a Group I pressurized enclosure, e.g. for a frequency convertor. 

Pressurization opens the way to a large-scale integration of components such as transformers, circuit breakers and contactors as well as frequency convertors into a single enclosure, thus replacing the multiple-housing switchboards in... 

Figure 6.20 Pressurized frequency convertor during assembly at the manufacturer s site.

Figure 6.30 Natural gas compressor at Groningen gas field/The Netherlands. Motor - Pressurized non-salient pole (synchronous) motor, frequency convertor fed. Type of protection EEx pe [ib] NO T3 Rated power 23 000 kW at 5400 min-1 Speed range 600... 6300 min-1 Voltage up to 2 x 3600 V Current up to 2 x 2030 A ...

Rotating electrical machines shall be tested at standstill and running with 0.9X 1.0X their rated speed. The rotor causes a certain turbulence of the test gas, resulting mainly in a considerably increased dp/dt value [2] and enhanced peak pressure. Cage induction motors may be fed from outside with an adjustable voltage and frequency via a frequency convertor, motors with sliprings or commutators need an auxiliary drive, e.g. a small cage induction motor powered by said frequency convertor. 

Frequency convertors - in the low voltage range - are designed according to flameproof enclosure - d - (Fig. 6.104) or to pressurization - p (Fig. 6.20), combined with e -terminal compartments for the most part. 

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