Electrical Power Systems Technology

Operational Power Control Systems 429

circuit will operate just like the circuit of Figure 16-1. The “jog” position

is used so that a complete circuit between L1 and L2 will be achieved and

sustained only while the start pushbutton is pressed. With the selector

switch in the “jog” position, a motor can be rotated a small amount at a

time, for positioning purposes. Jogging or inching is defined as the momen-

tary operation of a motor to provide small movements of its shaft.

Figure 16-1. A start-stop pushbutton control circuit with overload protection

(one-line diagram)

Figure 16-2. A start-stop control circuit with low-voltage protection and control

from three locations

Figure 16-3. A start-stop control circuit with a safe-run selector switch

Figure 16-4. A start-stop pushbutton control circuit with a jog-run selector

switch