Tech
Note
Most
DC motors are normally very easy to reverse,
simply changing the polarity of the DC input will reverse the direction
of the drive shaft. This changeover process can be achieved via a
simple changeover switch or for remote or electronic control, via
a suitable relay. When using a switch or relay always check the contact
current ratings and allow for larger currents to be switched, as different
mechanical loads and instant reverse can draw much higher currents
than when the motor is being run unloaded. Another big advantage of
DC motors is that variable speed control is easy and can achieved
with just a suitable variable resistor / rheostat or variable DC power
supply. For more precise control and maximum efficiency there are
many other electronic PWM (pulse width modulation) solutions, although
these tend to have added complexity. Most DC motors are designed to
exhibit the same speed and output torque in either the forward or
reverse direction. Drive shaft speeds rpm (Revs Per Minute) are quoted with motor unloaded.
World's
Smallest Motor ?
KV70
