elevmike
I bypassed this one due to the subject - motor question for DickDV.
A very major part of my business in the implementation of diesel generator systems. I have seen this and many other problems before.
Basically, the generator should have been sized for the largest load step. kW ratings mean nothing if the first load step is large.
Generally speaking, a generator can accept a 40% load step as the first step. The second step is then open to negotiation. Some generators can accept a 100% load step. These are only supplied if specified as they are expensive.
The basis is that the generator manufacturer usually supplies the smallest engine he can for the alternator size. This means that load steps are usually small. I commissioned a job recently where transisents were to be tested at 25% load steps. The last section of load from 75% loaded upwards could only be stepped on in increments of 5% or the set actually stalled. Very small engine for the alternator size. First time I have seen an engine stall on such small load steps (25%).
It may not be the generator suppliers fault either. it depends on how the job was specified. If your motor draws a high current on starting and that size load step was not specified, it is not the generator rep's fault but the specifiers fault. HE SHOULD HAVE SPECIFIED THE LARGEST LOAD STEP FROM COLD AND ANYWHERE ELSE IN THE LOADING STAGES OF THE SET!!!!!
Generally, if larger load steps are required due to inrush of this nature, the engine is sized up to suit the application. Sometimes the alternator has to be sized up as well.
With the set manufacturer supplying the lowest sized engine he can (probably lose the job supplying a larger engine) the engine may be just sized high enough to drive the load but not to handle the load steps. Another manufacturer may not have an engine of that horse power rating and have to supply an engine with a higher horse power rating. this means that the set from that guy would handle bigger load steps due to a higher horse power. If nothing was specified he would probably lose the job.
beerchug
