Sometimes instead of a pulley, a wheel with grooves on its circumference (Fig. 142) is used for rope transmission. The use of rope for the transmission of power is more common in Europe than in the United States. The advantages claimed for this method of power transmission are:

(a) A larger amount of power is transmitted.

(6) A rope can be run in any direction or to any distance.

(c) Smooth and quiet running is obtained.

(d) Electrical disturbances are absent.

(e) Economy is obtained in first cost and in maintenance. (/) There is an absence of slip.

For successful work the pulleys must be large in diameter and must have a smooth surface where the rope bears upon them. The speed and the load on the rope must be only such as experience has shown to be economical. When these conditions are fulfilled a rope drive is one of the most satisfactory methods of transmitting power.