Full Load Copper Loss

Stanford can give that. Please telephone Stanford directly with the serial number of the alternator and ask for technical assistance.

Only manufacturer can give you this data, check the alternator datasheet, or contact Stamford,

Simply put:

Copper loss = losses due to the pure resistance of the copper wires in the winding, with the current flowing through them.

Cu losses = Resistance x I²

Since the temperature affects the resistance value, then you need to measure that resistance for each phase after running the unit at near full load for some time to stabilise the temperature, then measure each phase to neutral resistance. Then multiply that value by the square of the full load current in each phase (don't forget the √3 when getting the current value (unless on name plate). Then add the 3 values to obtain the watts... This is the nearest you can get on site without any sophisticated set up.

Otherwise get the info from the maker of the Alternator (the supplier of the set or OEM could do the same from a certificate test sheet in his possession usually).

You have to measure the winding resistance with a 'four wire' ohm meter ...

Rudy,

You are correct. I did not go into the details of how to measure very small resistance values because this will entail some knowledge of the delicate procedures to avoid substantial errors at these levels.

The OP could use a DC voltage source and measure the current flow then calculate the rsistance value of a phase winding. But then he should already be familiar with the topic. my object was to indicate what was meant by copper losses. there is also the losses in the field windings which I forgot to point out...

In any case he better get the values from the OEM or Manufacturer of the Alternator. They will probably give him a standard value of the losses for serially produced Alternators...

Thanks for pointing out.