I am carrying out design appraisal of Rubber Tyre Gantry (RTG) crane. Manufacturer intends to provide a Genset with an engine of 397 KW and generator of 480 KW (600 KVA at 0.8 pf). Total load connected to genset is one hoist motor (1x185 KW), four gantry motors (4x30 KW), one trolley motor (30 KW). In addition to this there is an auxiliary load of 30 KW which includes lighting, control system power etc. Hoist, Gantry & Trolley motors are VFDs. Manufacturer has envisaged that hoisting & trolley operation may be simultaneous but has not envisaged gantry operation with hoisting. Further, though hoisting motor is of 185 KW, 230 kw power is required for hoisting operation during acceleration with rated lifting load. Manufacturer has stated that hoist motor can deliver 1.45x185 kw and hence motor is okay for 230 kw requirement. Similarly, I have checked the peak power requirement for trolley and gantry.
Maximum voltage drop allowed is +,- 5% as per the standard. Is there any thumb rule for sizing the genset ? I suppose since all main motors are VFDs, starting load should be restricted. Do you agree ? Engine & generator both have efficiency of 95%.
I would like to know if Geset sizing is okay. What happens to requirement of reactive load. Though generator is of 480 KW, engine is only of 397 kw, implying availability of only 397 KW. Please give your comments. I require your attention at the earliest.
Maximum voltage drop allowed is +,- 5% as per the standard. Is there any thumb rule for sizing the genset ? I suppose since all main motors are VFDs, starting load should be restricted. Do you agree ? Engine & generator both have efficiency of 95%.
I would like to know if Geset sizing is okay. What happens to requirement of reactive load. Though generator is of 480 KW, engine is only of 397 kw, implying availability of only 397 KW. Please give your comments. I require your attention at the earliest.
