Voltage inbalance on lighting load

[Tony@EEI]

i have temp service for a control houe @3 phase 208/120 volt,i have 120 volt lighting and 208/3phse ac units,with the lights on i have 6 amp on my neutral,i am bonded at the servie disconect,when my ac compressor engauges i trip at the generator,can you give me any advice on how to eliminate this problem?p.
i am able to run all 4 ac units if i leave the lights off and my neutral current is less than 1 amp,my lighting circuits are on A and B phase only

 

[iwire]

Is the breaker that is tripping a GFCI?

 

[Tony@EEI]

responce

responce

no this is a 100 amp main at the generator

 

[GoldDigger]

no this is a 100 amp main at the generator

My guess is that the line current in one or both of the phases from the lighting load only is high enough (at least 10 amps to produce 6 amps in the neutral if balanced between two phase lines) that combined with the starting surge of the A/C motor it is tripping at least one phase of the breaker, thus tripping the whole thing.

What are the FLA and LRA figures for the A/C?

You could have a problem with an undersized or defective generator breaker or a poorly matched trip curve. Just distributing the lighting load more uniformly might or might not help. A soft starting arrangement for the A/C may be the only way to go.