Bukhovtsev-et-al-Problems-in-Elementary-Physics

ELECTRICITY AND MAGNETISM 363
n
H
ing and their area, and H is the intensity
of the magnetic field of the
stator. which is directly proportional
to the current.
Upon excluding cCi from these equations,
we find that
U 2nMR
n= kH- k2H2
The relation between
shown in Fig. 476.
nand H is
Fig. 476
2nMR
If H H > H o , the speed increases
when the current grows in the windings of the stator. and decreases when H>Hm:
If the motor operates without load (M =0). the speed will be n= k~ ,
i.e., it always decreases with an increase of H.
616. The intensity of the current flowing in the winding of the motor
will be determined by the e.m.I, of the mains