2. Basic motor-control Circuit
-PILOT DEVICE
-Motor starter
PILOT DEVICE
a group of a components that include push-
button switches , limit switches and other
switches commonly found in motor control
circuit.
4. Figure 2. (a) fork lever roller yoke switch, (b)Roller arm limit switch, (c)
Top roller limit switch,(d) Wobble lever-actuated cat whisker limit switch,
(e) Side roller limit switch
Level switches
5. Control Circuit
-the control compnents ,which are the switches and coils that control the
load.
Load Circuit
- the load components such as motor that cause the system to perform
some type of action.
Figure 3. A Ladder
diagram of a control
circuit and a load circuit
6. Two-Wire Control circuit
Figure 4. (a) A wiring diagram of a two-wire control
circuit for a compressor motor (b) Ladder diagram
8. Three-Wire control circuit with Indicator Lamp
Figure 6. A wiring diagram
and a ladder diagram of a
three-wire control circuit
with a indicator lamp
9. Reverse Motor starters
Figure 7. A Ladder diagram and a ladder diagram
of a forward and reverse motor starter
forward reverse starter connection & working function & jo
10. Drum Switch
-a manual switch that allows you to manually reverse the direction
in which a motor is turning.
Figure 8. A drum switch
11. (a) (b) (c)
Figure 9. (a) Contacts of a drum switch when it is switched to the reverse
position. (b) Contacts of a drum switch when it is switched to the off
position. (c) Contacts of a drum switch when it is switched to the
forward position.
12. Figure 9. A single-phase AC motor connected to a drum switch and
A three-phase AC motor connected to a drum switch
13. Figure 10. A DC motor connected to a drum switch
14. Other Types of Pilot Devices
-Flow switch
(a device that monitors the flow of air, steam or liquid.
It sends a "trip signal" to a different device in the system, such as
a pump.)
-Level switch
(On-off switch that senses high or low liquid levels. A
displacer is used as the sensor and is located in an external cage
that mounts to the outside of a vessel.)
-Pressure switch
(a form of switch that closes an electrical contact when a
certain set pressure has been reached on its input.)