400 Hz. Motor Generator 1

[EEJaime]

Good Morning,

I am working on a project at an airport where we need to re-work some of the 400Hz. 480v. Ground Power supplies for the aircraft and loading bridges. The existing rotary frequency converters are old "Hobart" units, which I can't find any information on. This is not our specialty, so I have a limited list of information sources. Internet searches have provided some vendor information, but I am looking for information which will provide some system design guidelines, technical specifications, space requirements, etc.... Any information that someone can point me to, would be greatly appreciated. The loads the new Airbus A380 and it's associated dual stacked loading bridges require are larger than the existing system can support so the system will need to be expanded to accomodate the added loads.

Thank you in advance for your assistance.

EEJAIME

 

[mc5w]

Back in the early 1980s I was able to get a drawing and schematic from Hobart for a motor generator that they had built for the Signal Corps during World War 2. This unit was really a welding generator that was readily adapted for charging a 24 volt battery which requires 32 volts open circuit and 28 to 30 volts closed circuit to fully charge the battery. You just need to talk to the right person.

Have you asked the Airbus people for a referral to an MG set manufacturer?

Marathon makes some 400 Hertz generators that are connectable for 120 volts delta, 240 delta, 120Y208 volts, and 240Y416 volts. You probably can get them to build you units that are 277Y480 volts for your application. Your load is probably greater than their standard units. Since Marathon also makes motors they could build the whole blooming thing for you.

You would need to also order these as 2 bearing units which does not cost extra. You would then need to direct couple a motor to the generator possibly using a variable frequency drive at say 55 Hertz into the motor or whatever it takes to get 400 Hertz.

You also need to watch the surge rating of the 400 Hertz generator to be sure that it is adequate for inrush and locked rotor current.

You could also use a variable frequency drive to produce 400 Hertz that then goes through a drive isolation transformer. Both the drive and transformer in this size range would need to be special order since most 100 KW and larger drives are only rated for 200 Hertz maximum. The drive would also need a continuous rating greater than or equal to the inrush current of your load and the locked rotor rating of your motors that start across the line. This could make the VFD option more expensive than and MG set.