Gensets and Chiller Compressors

A genset needs to be sized to handle all the loads that will be imposed, plus sufficient reserve to be able to start the largest motor. The 120 hp chiller equates to 89.52 kw. Conservatively assuming a power factor of 0.85, this is 105.3 kva. With reduced voltage starting (or soft start or VFD), this looks okay, so long as no other large loads are present when starting the chiller. Once the chiller is running, other loads could then be added.

The chiller control system should also ensure that the chiller starts unloaded, and then loads up after reaching full speed.

Check also with the genset manufacturer. It may be rated as to the largest motor it can start under various types of starting.

Thank you for improving on my earlier answer. I think we are agreed that the OP's application looks good, and I am glad to have this additional information. I would give it 2 GAs if I could.

you need to check the Rating of the genset (Standby/Prime/Continues) if its standby set you need to discuss with genset engine manufacturer, second check Block load characteristics of genset engine manufacturer which will help you better.

crm

I would like to know the starter type for this compressor. If it is DOL, then definitely the DG set will sink during starting of this appliance. If reduced voltage starting, may be star-delta or auto-transformer, the DG set might just handle the situation, depends upon the base load on the set at the time of starting the chiller. A VFD would definitely help as all VFDs are soft starters inherently. The DG set will definitely handle the starting of this chiller if the chiller is driven thro a VFD. But a word of caution - check for harmonics from the VFD. It might cause voltage distortion in the DG set.