Industrial Control Devices: Switch, Relay, Solenoid and Timer
CONTROL DEVICES
Switch Abbreviations NO (Normally Open) and NC (Normally Closed) represent the electrical state of this switch contacts when the switch is not actuated.
Manually Operated Switches - Switch is controlled by hand. - Forms of switches i) Toggle switch (Types of switches:- ➢ Single Pole Single Throw (SPST) ➢ Single Pole Double Throw (SPDT) ➢ Double Pole Single Throw (DPST) ➢ Double Pole Double Throw (DPDT) ( Electrical ratings are expressed in terms maximum interrupting voltage and current; should not be exceeded. ( AC and DC ratings are not the same for a given switch. The DC current rating of a switch would have a lower magnitude than the ac rating.
[pic]
Figure 1: Toggle Switches
ii) Slide switch ( uses a simple slide action to produce the same connections as a toggle switch. (used as a mode switch to select a certain mode of operation such as HIGH and LOW. [pic] Figure 2: Slide Switch
iii) DIP (dual in-line package) switches ( small switch assemblies designed for mounting on PCB. ( The pins or terminals on the bottom of the DIP switch are the same size and spacing as an IC chips. [pic] Figure 3: DIP Switch iv) Rotary switch ( often used for more complex switching operations, such as oscilloscopes and multimeters. ( wafer switch # the main shaft passes through the center of one or more ceramic, fiberglass or phenolic wafers on which the terminals and contacts are mounted. # the center section of each wafer can be rotated, passing a common contact to one of the many stationary contacts mounted around the wafer’s perimeter. [pic] Figure 4: Rotary Switch
v) Thumbwheel switches ( used on numerical and computer-controlled equipment to input information from the operator to the computer. ( Their specially made decks
Switch Abbreviations NO (Normally Open) and NC (Normally Closed) represent the electrical state of this switch contacts when the switch is not actuated.
Manually Operated Switches - Switch is controlled by hand. - Forms of switches i) Toggle switch (Types of switches:- ➢ Single Pole Single Throw (SPST) ➢ Single Pole Double Throw (SPDT) ➢ Double Pole Single Throw (DPST) ➢ Double Pole Double Throw (DPDT) ( Electrical ratings are expressed in terms maximum interrupting voltage and current; should not be exceeded. ( AC and DC ratings are not the same for a given switch. The DC current rating of a switch would have a lower magnitude than the ac rating.
[pic]
Figure 1: Toggle Switches
ii) Slide switch ( uses a simple slide action to produce the same connections as a toggle switch. (used as a mode switch to select a certain mode of operation such as HIGH and LOW. [pic] Figure 2: Slide Switch
iii) DIP (dual in-line package) switches ( small switch assemblies designed for mounting on PCB. ( The pins or terminals on the bottom of the DIP switch are the same size and spacing as an IC chips. [pic] Figure 3: DIP Switch iv) Rotary switch ( often used for more complex switching operations, such as oscilloscopes and multimeters. ( wafer switch # the main shaft passes through the center of one or more ceramic, fiberglass or phenolic wafers on which the terminals and contacts are mounted. # the center section of each wafer can be rotated, passing a common contact to one of the many stationary contacts mounted around the wafer’s perimeter. [pic] Figure 4: Rotary Switch
v) Thumbwheel switches ( used on numerical and computer-controlled equipment to input information from the operator to the computer. ( Their specially made decks