DC Loading and Alternator Efficiency

What is it about the load that makes you think it would have any bearing on the efficiency of the generator? Am I missing something?

Or... how is a device meant for a DC source magically going to coax a DC current from an AC source, if that is what you are implying? Your statement about the rectifier is confusing.

The alternators are rated for 0.8pf lag. The derating will depend on deviation from 0.8pf lag towords lead. THe rectifiers will have low powerfactor and generate harmonics depending on scheme. Hence there would be loss and affect on efficiency

Why r u concerned,calculate the \DC load like any other load connected to the generator ,some efficiency loss on the rectifier is negligible.

You have not given the figures , type of load,alternator/Rectifier 3 PH or 1PH unless it is a heavy load where you need to consider harmonics from rectifiers.

friends,

I clearly want to ask that if we have 3 phase alternator of rating 3MW , 440V to feed load of 3MW (not consider single load it might be combination of many equipment total of which is 3MW), now some how same alternator have to connect to DC load(after disconnecting from previous circuit) so what will be the new load capacity which alternator can provide.

for dc load we have to convert ac to dc.

there must be some derating factors - I come to know that the efficincy will become 30% only. is this true, this figure is come from alternator suppliers.