Marine motors

[davhardy]

Most 3 phase motors installed on board naval ships and other vessels are star (Y)connected. This contrasts with most industrial machines which are delta connected. Can anyone advise the reason for this? It may be associated with the normal 440V 60Hz ship supply being a floating 3 wire system but I am not certain.

What would be the problem, if any, in applying a delta connected motor on board a ship?.

Would apreciate any advice.
Regards

Dave H

 

[aolalde]

davhardy:

Industrial applications are not restricted to delta connection of three phase motors; I have seen both connections in small, medium and large size motors.

I don’t know if there is a regulation or naval standard asking for motors restricted to wye connection.

Wye connected windings with solid grounded neutral almost completely suppress the triple harmonics (3rd and odd multiples).

Considering the insulation stress, when properly spaced, the wye connected motors have a gradual reduction of potential toward the neutral reducing the electric field stress of the insulation. Delta connected motors put the line potential to each end of the phase winding.

However I had not seen any report blaming delta connection as cause of premature insulation failures.

 

[jbartos]

Suggestion: Y-winding motor can be made lighter and physically smaller than Delta winding motor. These are important criteria for the shipboard applications.