Define critical field resistance for a DC generator.
1
It is the highest value of resistance of the series field circuit with which a DC generator can build up its voltage.
2
It is the highest value of resistance of the shunt field circuit with which a DC generator can build up its voltage.
3
It is the lowest value of resistance of the shunt field circuit with which a DC generator can build up its voltage.
4
It is the lowest value of resistance of the series field circuit with which a DC generator can build up its voltage.