Positive SSL
1 有一5kW、100V直流分激式發電機,場電阻為100Ω,當供給額定負載時,應電勢為120V,若電刷壓降忽略不計,則電樞電阻約為多少Ω?
A 0.68
B 0.53
C 0.47
D 0.39

`I_L =P/V_t` = `(5xx10^3)/100`=50A

`I_F=V_t/R_F`=100/100=1A

`I_A=I_L+I_F`=50+1=51A

`E=V_t+I_AR_A`→120=100+51×RA

RA=0.39Ω