Control circuits pdf

Notice that the stop pushbutton is in series with coil M, and that the start pushbutton is in parallel with M contacts 2–3. The entire control circuit in this example is in parallel between line and line 2. These basic relationships can be found in many control circuits. A very common form of latch circuit is the simple ”start-stop” relay circuit used for motor controls, whereby a pair of momentary-contact pushbutton switches control the operation of an electric motor. A wiring diagram gives the necessary information for actually wiring-up a group of control devices or for physically tracing wires when trouble-shooting is necessary.

DC-DC converter control circuits Datasheet -production data Features Output switch current in excess of 1. A reference accuracy Low quiescent current: 2. The interlock contacts installed in the previous section’s motor control circuit work fine, but the motor will run only as long as each push button switch is held down. If we wanted to keep the motor running even after the operator takes his or her hand off the control switch(es), we could change the circuit in a couple of different ways: we could replace the push button switches with toggle. A control relay is an electromagnetic switch that opens and closes a set of contacts when the relay coil is energized.

The relay coil produces a strong magnetic field which attracts a movable armature bearing the contacts. Control relays are mainly used in low-power circuits. Based on your observations of these two diagrams, explain how electromechanical relays are represented differently between ladder and schematic diagrams. Interpret this AC motor control circuit diagram, explaining the meaning of each symbol: Also, explain the operation of this motor control circuit. At this point the problem could be mechanical or electrical.

We will focus on just the electrical circuit faults for now. The electrical power used to energize a circuit in which a particular output is expected is sometimes referred to as ”excitation. Bridge circuit power supplies are another example of an ”excitation” source. This is a very important, but often misunderstoo aspect of DC motor control.

Electrical Circuits A complete path, or circuit , is needed before voltage can cause a current flow through resistances to perform work. There are several types of circuits , but all require the same basic components. A power source (battery or alternator) produces voltage, or electrical potential. In this book, we try to avoid or at least minimize discussions on the theory and instead focus on showing you how to troubleshoot electrical equipment and control circuits. The book helps to increase your knowledge and skills in improving equipment productivity whilst reducing maintenance.

Learning 1- Basics of Motors and Motor Controls. This is an excellent book, requested to make control circuits easy to understand for the electrician that is unfamiliar with controls. LADDER LOGIC Ladder diagrams Ladder diagrams are specialized schematics commonly used to document industrial control logic systems. They are called ladder diagrams because they resemble a ladder, with two vertical rails (supply power) and as many rungs (horizontal lines) as there are control circuits to represent.

In Theory and design of Electrical and Electronic Circuits you can find primarily the generalities of circuits. A power circuit provides significant electrical capacity to operate something that does a lot of work, for example high power heaters or multi-horsepower motors. This type of flow control circuit bleeds off excess fluid to tank.

A bleed-off circuit works best in hydraulic circuits using fixed-volume pumps. And a bleed-off circuit only works with multiple actuators if they operate one at a time. If not under control , useful work will not be done and machinery or machine operators might be harmed. One of the advantages of transmitting energy pneumatically is that energy can be controlled relatively easily by using valves.

This is done, using ladder logic diagram, statement lists, or control flowcharts software, by representing the logical conditions, sequences, and interlocks required for operating equipment or a machine in an automatic sequence. To understand how to troubleshoot control circuits. When using a step-by-step analysis approach to troubleshooting, the first step should be.