7
FIGURE 9. PERMANENT–MAGNET STEERING
BATT
ARM
6928
Series Wound
Series wound motors have the field coils connected in
series with the armature circuit. The same current flows
through the armature windings and the field windings.
In a series motor, the torque varies inversely with the
speed. Under conditions of light load, there is high
speed and low torque. Under conditions of heavy load,
there is low speed and high torque. Series motors are de-
sirable in some hydraulic systems where a light load can
be raised fast and a heavy load at a slower speed. This
gives the effect of a two speed hoist system. The series
motor has high starting torque and quick acceleration.
This characteristic makes it ideal for lift truck traction
systems.
FIGURE 10. SERIES HOIST MOTOR DIAGRAM
BATT
ARM
6929
