The grounding issue put forth by the technical people you post in that doc indicate to me that they are clueless. If this is a standard induction motor as the prime mover and based on your indication that the input current is 115 amps
@480 that would seem to indicate about a hundred HP motor. I would be inclined to think that your 200 amp input breaker is way to small even if started unloaded.
Not so fast.. . . . hold on to your horses.
The disjointed question elicit responses that often lead to confusing and convoluted answers –and also become a
“horse and pony” show
The above response is one of them.
The post above is replete with statements that indicate lack of understanding of MG Sets. But that’s OK.
It would have been better if presented in an interrogative . . . not a faulty declarative form.
Incomprehensive responses open a slew of questions that can lead to a more in-depth examination of the issue at hand.
As mentioned by OP this application pertains to aircraft.
Having been involved in Military projects-- since the company that I worked for years ago—our company (a consulting firm) took responsibility in designing equipment (in collaboration with Military personnel) intended primarily for the support of the military establishment.
Check out MIL-STD-704.
We had our own Research and Development Department typical of big government contractors like United Technologies, Lockheed, Northrup Grumman et al.
I’m not a military personnel who is bound for the battlefield. . . just a civilian engineer contractor through my employer.
I am now retired however.
M-G Sets are the “go to” systems for aircraft power systems but they are also used in ships and mobile equipment. (rocket launchers etc.)
The big supplier of these units is
Ward-Leonard.
GE also is a big player in this field.
The claim by other posters that M-G Sets are inefficient is flying in the face of naivete (utter ignorance).
M-G Sets are indispensable in the design of equipment when it comes to efficiency and reduced weight.
And operating at 400 Hz is also a bonus. . . hence used in aircraft.
To OP:
A 400 Hz electric motor for example has less iron compared to a regular induction type at 60 Hz motor.
Smaller physical size on motors and generators
Another curiosity in the query – is, why (OP) is perplexed on how to ISOLATE the MG grounded neutral.
The ISOLATION of the Motor Neutral from the GENERATOR Neutral is explicitly noted in the single line diagram.
Neutral isolation between M and G is important
(check the foot note on the single line diagram)
Pay close attention to the recommendations by the manufacturer . . . . they’ve been around longer than any of us in this midst.
I have few question to ask. . . but I will hold off until you had a chance to read the following article.
I will ask those questions if only to elucidate what seem to be muddled. Of course it is contingent upon whether you are still interested in forging forward,
Asking more question only complicate things even more.
We’re here to answer questions as best we can. . . not answering with another question.
To get familiar with the advantages and disadvantages of 400 Hz
power systems, Google the title
“The Basics of 400 Hz Power System”
The following is an informative "White Paper" from EC&M.
h
ttps://www.ecmweb.com/basics/article/20897812/the-basics-of-400hz-power-systems
