FIGURE 4
FIGURE 5
The plot in Figure 4 shows that:
• The maximum speed ω no_load
happens when the motor shaft is
free of external loads, with τ = 0.
Example: Magmotor
S28-150
The guide calculates the values
(shown in Figure 5) for the popular
Magmotor S28-150 connected to
one NiCd 24V battery pack. The
guide’s “teaching point” — aside
from providing sample calculations —
is twofold.
Typical
Brushed
DC Motors
The Magmotor
example can be
repeated for several
other motors. Table 1
shows a few of the
most used motors in
combat robots and
their main parameters.
Several parameters are
based only on motor
specs (as a standalone
item). Their actual values in a
battery/controller/
wire/motor system would not be as
good. (Note: Kt and Kv — not used
elsewhere in this summary — are the
motor torque and motor speed
constants.)
32 SERVO 01.2011
