In earlier days instead of plc or dcs like controllers relays are used as controllers. Relay contact symbols are shown with the same numbers or letters.
Automotive Relay Guide 12 Volt Planet
How to read a relay schematic. Electrical control circuits are drawn with the standard. Nowadays also for controlling small systems relays are using as controllers. Nets are represented as lines. Reading a schematic diagram is similar to reading a book. When theyre integral to the control unit the diagram will often refer to it but it wont be a serviceable relay. Wiring diagram for automotive relay wiring diagram mega switches relays and wiring diagrams 2 youtube how can i add additional circulator relay to existing thermostat.
Because of this feature it eliminates most dedicated control wiring that would normally be wired from relay to relay ie. The following schematic shows the basic circuit. Due to this digital communication between relays a typical dc schematic diagram alone is not an adequate method for describing the system. Now lets look what is electrical relay diagram. A trip output contact from one relay to the input coil of another relay. In one of the previous post in instrumentpedia i have described how to read an electrical drawing.
Normally open no contacts connect the circuit when the relay is activated. Connect the relay with hc11 port pins this is used to control on switches. It is read from left to right and from top to bottom. The circuit is disconnected when the relay is inactive. Relay configurations and types. How to read relay wiring diagram another image.
Commit the following rules to memory. But you can also use the. C denotes the common terminal in spdt and dpdt types since relays are switches the terminology applied to switches is also applied to relays. Running high amps through a small switch would cause the switch to burn out and fail possibly starting a fire. They are usually represented by zig zag lines with two terminals extending outward. The function of a relay is to control a high amp circuit like a starter motor or head lights using a low amp switch circuit.
Schematic nets tell you how components are wired together in a circuit. Traditionally relay terminals were numbered using double digits but. It is also called form a contact or make contact. Reading wiring diagrams and understanding electrical symbols reading wiring diagrams and understanding electrical symbols to understand how to read ladder wiring diagrams we are going to start with a simple power supply switch and light then we will move on to our control panel. Now all that remains is identifying how all of the symbols are connected together. Here i am giving the standard symbols used for the electrical relay diagram.
Recognizing electrical schematic symbols here are some of the standard and baisc symbols for various components for electrical schematics. Circuit symbols of relays. Nets nodes and labels. The numbers 85 86 30 87 87a or other numbers for different relay configurations are normally moulded into the plastic next to each pin and also shown on the circuit schematic. Relays are common in circuits and also housed within control units. Understanding which components are which on a schematic is more than half the battle towards comprehending it.
Electrical symbols are always shown in their off or deenergized position. Resistors are the fundamental components of electrical schematics. The diode prevents relay from arcing by giving a return path for the energy stored in the magnetic field of coil extending the life of relay. To read electrical schematics the fundamental electrical schematic symbols should be understood. In addition to the basic make break and changeover configurations above iso relays are available in a number of other common configurations which are described in the table below. A relay switches one or more poles each of whose contacts can bethrown by energizing the coil in one of three ways.
The transistor allows the hc11 to control the medium sized coil current of relay. Then well talk about how those symbols are connected on the schematics. Comparing to other controllers it is very cheap. A very high resistance or open circuit reading can indicate a damaged coil.
Gallery of How To Read A Relay Schematic
