What is the difference between the vacuum pump condenser and ejecteur condenser power plant steam turbine?

As we know that in the last stage of Turbine low pressure sream is enter in to the condenser,because Condenser having more vacuum than Turbine. As per theory wnen1 kg of steam is converted in1 kg of water, there specific volume ratio will be1/1800.So when steam is converted in water volume will reduce.Volume is automatically created.

But to maintain vacuum in Surface condensor we need Ejector or Vacuum pump.Now Ejecter is just like Divergen/Convergent nozzle.when bleed sream will enter into Nozzle,it creates vacuum & converted into water.now this Ejector is connected with Main condensor.So it cotiniously maintains the vacuum in Condensor.In most of the Condenser we use Ejector.

But Motor driven Vacuum pump will also serve the same.Except any case if Motor driven Vacuum pump will trip, TG is in danger,May be trip in Low vacuum.Ft that you requir UPS driven/DC Driven Vacuum pump.

Vacuum system

For water-cooled surface condensers, the shell's internal vacuum is most commonly supplied by and maintained by an external stem jet ejector system. Such an ejector system uses steam as the motive fluid to remove any non-condensible gases that may be present in the surface condenser. The Venturi effect, which is a particular case of Bernoulli's principle, applies to the operation of steam jet ejectors.

Motor driven mechanical vacuum pumps, such as the liquid ring type, are also popular for this service.