Between Parallel Generator and Single

There is no such thing as a generator to be used exclusively in parallel.

However, there might be various limited and/or malfunctioning generators that can be used only in island (single) mode....

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I heard an issue told about special generaator for parallel. That why I want you guys opinion. thanks

Hmm? If it can work only in parallel, what happens until you get the other one(s) running??

........and do these other ones only run in parallel too? Curious minds want to know.

Oh, part 2: besides a Megger^® test (phase to ground), a continuity test (phase to phase) would be useful.

You seem to be out of your field!

All generators can work single or in parallel. The differenceis that you need some special extra equipment to be able to use a generator in parallel with another source of electrical power....

On the winding issue: Too complicated for you. just check if the winding reads to ground or body of the alternator, using a megger: This is an insulation test only. If the reading is less than 2 or 3 mega Ohms, then you might have a problem...

The KVA ratings of the two generators to be paralled must be within 3:1 for proper loadsharing.

Apart from meggar( IR test) test, P.I.( Polarisation Index ) test; i.e. ratio of I.R. value of 600 secs to 60 secs, sholud be done either by motorised meggar or P.I. tester ; in general for solid insulation, P.I. value should be greater than 2.0. Comparison of % inductance and resistance values ( Phase to Phase and Phase to Neutral ) should be checked by Electric Motor Checker instrument; for healthy generator, the % varaiation should be within 5%.