what determine the alternator output current

[tor12]

Do alternators obey Ohm’s law? The alternator output voltage is proportional to the rotor excitation current. When reducing rotor excitation, the output voltage drops and the load resistance stays constant. Can why still use ohm law to determine the output current.

Example alternator 480 v / 4 ohm current output is 120 a if why now reduce rotor excitation output voltage drops tu 220 v / 4 ohm output current is 55 a can why calculete like this.

Another example is car alternator have 900 w of pawer tu give that pawer with 13.7 v output current is 65 a and load resistance is 0.21077 this all calculation are based on ohm low.

Can why calculate like this of course every equipment must support rated current

also i understand principle of impedance can why calculate a show i above examples

 

[kenny7askew]

alternator on my cooper s was useless,seemed like every winter i needed a new one

 

[dmxtothemax]

As alternators are an inductive device
Then it is NOT just ohms law and straight DC resistance.
Your dealing with impedance not just resistance.

 

[Lucien Nunes]

Under normal running conditions, the output of an alternator is limited instantaneously by demagnetisation (caused by output winding reaction) and over a longer time constant by thermal dissipation. Without voltage regulation, the dynamic output impedance comprises both electrical and magnetic components and is not a straight line over the entire output range because the magnetisation curve is not linear. With voltage regulation in use the effective impedance is the slope of the regulator, not the machine characteristic. Only under momentary short-circuit conditions is the impedance of the winding predominant.