High torque low speed motors are used in a variety of applications and they come in a variety of forms. Electric high toque low-speed motors can be powered by either DC (direct current as from a battery) or AC (alternating current as from wall socket).
The motors can be direct drive or have a gearbox that enables them to run at variable speeds. Gear ratios can be anywhere from 1:1 to the extreme 1:1000. A gear ratio of 1:2 means that the input shaft and the output shaft turn at different speeds with one turning twice as fast as the other. Some DC motors can easily reverse direction by simply changing the polarity.
Typical of mechanical systems, power and speed are tradeoffs. Instead of the word "power", the technical term "torque" is used in the context of rotational motors.
High torque low-speed motors are designed for applications that require a lot of power, but not a lot of speed. These high torque motors can rotate against large resistance and are especially suitable for applications that require a large initial starting torque. However, they do not rotate very fast. Hence they do not have a high RPM (revolution per minute).
In specifications, you often will see a sloping speed-torque curve where torque decreases as speed increases.
In certain applications, the speed can actually be zero with no rotor rotation. For example, an induction torque motor is designed to supply a constant torque whether it is turning or not. It can run indefinitely under a locked-rotor condition without damage to itself.