What‘s The Advantage And Disadvantage Of Four Winding Transformer?

The busbar voltage is 11kV.

What is the motor voltage for Thruster B?

Sorry,I did not state fully,and there would be another transformer for Thruster Utilities...

That sounds like a disadvantage.

What is a "thruster" here?

Electical propulsion of a ship....propeller

Since the system is for marine craft, one has to follow the code laid out by the classification society & IMO regulations. Pray, who are the consumers, you are talking about on a marine craft?

the price of the transformer may have been the cause for the choice... and the space it occupies. one thing I do not understand are those motor driver´s.

what are they doing exactly?

If the supply to thruster B fails, the supply will be maintained to thrusters A and D, meaning that the ship continues to have mobility, albeit at a reduced rate.

If there was no duplication of supplies to thrusters, then a single failure could leave the ship "dead in the water", which would have safety implications for all on board.

Try looking up Kramer variable speed drives. That transformer isn't all it appears.

Your opinion, I am afraid, is all wrong & wild imagination. The inbuilt design, is capable of performing under all circumstances. Sit down with your Chief Engr. with your schematics & get your doubts clear. If you are not the electrical Officer, sit down with him. If still you don't get an answer, wait till the next survey, see if your Class surveyor will oblige you. Or get somebody to pen your thoughts coherently on this thread. Good Luck!

Maybe you are right...

thanks for your advice..

I don't claim to know much about these kind of drives,. But it looks like the four winding trasnformer is giving the equivalent of six phase (using two secondary widings) connection to the inverter. this will reduce harmonics and provide a smoother supply. The third secondary winding to thr. Utilities is to separate the supply to the electronics from the main drive power supply, perhaps because a different voltage is required and or to provide a cleaner supply to the electronics. (a level of separation from the dirty supply to the inverter).

I think you are right.

GA but I'm thinking that this is an AC Thruster Drilling Rig, 11kv bus and 4500kw thrusters point to the new rigs with ABB water cooled medium voltage inverters running the thrusters. For sure that kind of transformer is used to drive a 12 pulse DC SCR Rectifier for the reasons you say.

Yes Sir. Your presumption about this being a drilling/oil rig is also correct.

I'll really go out on a limb now and say it's one of the Transocean Deepwater DP Drill Ships (lost the only DP Semi the Horizon, the Nautilus is moored) built for R&B in Korea.

So their using this transformer to optimize 12 pulse because the DC front end of the Thruster Inverter's are 12 pulse? I can buy that but would like conformation, the Inverters I worked on were on the Drilling end, I don't even know if the thruster inverters were regenerative.

We hope, the OP will confirm or refute soon.

Semi-submsersible drilling rig is right. With DP3 dynamic positioning and mooring positioning . built for COSL in china.

Thank u very much.

You and all other participates did clear my doubts .

You all make CR4 an excellent discussion forum..

The answers are simple for electrical engineers . . .

You have a primary . . . .

You have a Delta and a Star secondary windings feeding a 6-phase rectifier . . .

You have a service power or utility winding.

This is a little out of my realm of experience, but if memory serves me correctly, a delta-wye transformer will give you the ability to drive a twelve pulse rectifier to drive the DC link on the motor controller.

Check out page 21 of this document from ABB.

http://www05.abb.com/global/scot/scot201.nsf/veritydisplay/6dff3290e5f2d651c125788d00393a58/$file/abb_technical%20guide%20no.6_revc.pdf

This is probably an even better reference.

http://www.mtecorp.com/12pulse.pdf

Good luck with your quest !!

"What's The Advantage And Disadvantage Of Four Winding Transformer?"

Each is designed for a specific purpose/service. They can not be subjected to any comparison.

Advantage:

1. Space saving

2. Less Copper, cost saving

3. Harmonics will be absolutely zero, system will not be affected by harmonics due to

load.

4. You can operate different voltage equipments / 3ph 3wire + 3 ph 4 wire together.

Mr. Potter.

Don't comment on concepts you don't understand.

You wrote: Harmonics will be absolutely zero, system will not be affected by harmonics due to load.

This is wrong. Go back to school. You can reduce the harmonics but never (cost effectively) eliminate them completely.