Biomedical Engineering Reference
In-Depth Information
FIGURE 3-12
Relationship
between motor
speed and torque for
a DC motor.
FIGURE 3-13
Effect of changing
the applied voltage.
The output power,
P
mot
(W), supplied by the motor is equal to the product of the torque
and the speed.
P
mot
=
ωτ
(3.24)
Therefore, at the two extremes no power is output, and a maximum occurs at the
center of the graph where
2. This relationship, which equates to
the area of a rectangle below the curve, is shown graphically in Figure 3-14.
ω
=
ω
n
/
2 and
τ
=
τ
s
/
3.2.2.3 Real Motor Characteristics
A 2W Maxon motor designed to operate from 15 volts has a no-load speed of 7160 rpm
(750 rad/s) and a stall torque of 5.53 mNm. The relationship among the torque, output
FIGURE 3-14
Relationship among
speed, torque, and
output power.
(a) Low speed.
(b) Moderate speed.
(c) High speed.
