The german trade associations demand that, for control systems of powerdriven metalwork presses, the contacts of contactors. Safety relays 5 the figure below shows a typical control circuit with a master control relay. Normally these contacts are not used in motor circuits. Perhaps the most common industrial use for contactors is the control of electric motors.
When a relay is used to switch a large amount of electrical power through its contacts, it is designated by a special name. Auxiliary contacts of contactors are used in control circuits and are rated with nema contact ratings for the pilot circuit duty required. An actuating current on a coil operates one or more galvanically separated contacts or load circuits. It is crucial to have a good basic understanding of the principles behind safety relays and safety circuits.
Communication ability full protection normal, reverse control of motor circuit. Only a small amount of control current is required by the magnetic contactor to open or close the circuit. Industrial control and systems controllers, contactors and. This circuit works fine, if we can assume that crb never welds. Control elements the elements of a control circuit include all of the equipment and devices concerned with the circuit function. The coil voltage of a contactor or relay can be installed for virtually any control circuit voltage, to provide complete flexibility for these devices both ac and dc, as the control circuit. Pdf schneider electric wiring diagram book engineer bilal nasir. When the coil is energized, the moveable contacts are closed against the stationary contacts, thus completing a circuit. Control circuit of dol starter control circuit of fully automatic starter auto transformer working and saving in copper material speed control. Maximum backup fuse for shortcircuit protection gl and gg. Motor control circuits ladder logic electronics textbook. Contactors for mediumvoltage motors greater than 1,000 volts are rated by voltage and current capacity. This includes enclosures, conductors, relays, contactors, pilot devices, and overcurrentprotection devices.
The control circuit has a small control coil while the load circuit has a switch. Contactors are used to electrically turn on or off high current, nonmotor loads or in motor loads where overload protection is separately provided. Safety relays are a special type of relay you can use to build a safety circuit. The employers liability insurance association demands that, for control systems of powerdriven metalwork presses, the contacts of contactors must be interlocked and opposing. The circuit that applies the voltage to the coil is referred to as the control circuit, because it controls the main device that the contactor or relay is switching. However, the basic difference between the relay and contactor is that the contactor is used in applications with higher current carrying capacity, whereas the relay is used for lower current applications. The top three contacts switch the respective phases of the incoming 3phase ac power, typically at least 480 volts.
Manual power control, automatic when associated with a contactor full protection and onoff control of motor circuit. The vcontact vsc contactor introduces the drive with permanent magnets, already widely used, experimented and appreciated in medium voltage circuit breakers, into the worldwide panorama of medium voltage contactors. Motor protection and control manual motor starters, contactors and. Nema and iec schematic diagram comparisons mz081001en. One coil, momentarily energized, closes the power circuit contacts, which are then. All dil contactor relays have doublebreak contacts. Contactor control through asinterface by way of terminals. Disconnection, short circuit and overload protection.
Siemens industrial controls catalog is an extremely interactive catalog with page links, bookmarks, and a search engine. When a relay is used to switch a large amount of electrical power. Contactor control automation technology plc hps systemtechnik. Abb offers protection against shortcircuits, phase failures and. Miniature and motor contactors, auxiliary contactors and. Industrial controls catalog industrial controls sirius. The interlock contacts installed in the previous sections motor control circuit work fine, but the motor will run only as long as each push button switch is held down. There are posts on the working of relays, types of relays and so on. The magnetic coil is switched directly on and off with the control supply voltage. The electro mechanical relay is a remote controlled switch capable of switching multiple circuits.
Voltage ue up to 500 v ac current ie up to 5000 a contactor type ac control circuit iorr800 iorr iorr1400 iorr1700 iorr2100 iorr2500 iorr3200 iorr3800 iorr4500 iorr5100 dc control circuit. All moeller contactor relays have doublebreak contacts. The electro mechanical relay is a remote controlled switch capable of switching multiple circuits, either individually, simultaneously, or in sequence. R contactors control of ac and dc power circuits up to 5000 a. It can be used for switching of small lights, sirens, indication lamps etc.
In summary, contactors operate electromechanically and use a small control current to open and close the circuit. Relays are switching devices used in any control circuit. Control panel technical guide how to quickly design optimized. Shortcircuit protection of the contactors without overload relay, see technical. To confuse things a bit, contactors are often fitted with auxiliary contacts which can be no or nc however these are used to perform additional functions related the control of the contactor. The coil voltage of a contactor or relay can be installed for virtually any control circuit voltage, to provide complete flexibility for these devices both ac and dc, as the control circuit can be completely independent of the load it is switching. To reduce power consumption in the contactor coils, latching contactors are used, which have two operating coils. Control circuits can be represented pictorially in various ways. A control circuit shown in green and a load circuit shown in red. 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. In the jog position, the holding circuit is broken and jogging is accomplished by depressing the push button. Voltage ue up to 500 v ac current ie up to 5000 a contactor type ac control circuit iorr800 iorr iorr1400 iorr1700 iorr2100 iorr2500 iorr3200 iorr3800 iorr4500 iorr5100 dc control circuit iore800 iore iore1400 iore1700 iore2100 iore2500 iore3200.
They are used for switching multiple control circuits and for controlling light loads such as starting coils, pilot lights, and audible alarms. The contactor operates by applying a control voltage to the contactor coil. All control circuit components are shown as directly as possible, between a pair of. When the start push button is pressed, the control relay. A simple circuit diagram either of the two start buttons will close the contactor, either of the stop buttons will open the contactor. Contactors electromechanical relays electronics textbook. Contactors contactor a control device that uses a small control current to energize or deenergize. Notice and disclaimer the information in this publication was considered technically sound by the consensus of persons engaged in the development and approval of the document at the time it was developed. The experience acquired by abb in the field of medium voltage circuit. For example, the contactor may transmit power to the motor, while the auxiliary contact is in the control circuit. Multipole lighting contactors 5060 hz power poles for type l or lx the kits below are used to add 30 ampere power poles to existing type l contactors when additional circuits are required. Lamp light control circuits electronics tutorial and emitter is used as a common terminal by the power circuit and by the control circuit, 2 gheorghe asachi technical university of iasi, power electronics laboratory being assimilated as a ground gnd point common emitter topology. Lamp light control circuits electronics tutorial and emitter is used as a common terminal by the power circuit and by the control circuit, 2 gheorghe asachi technical university of iasi, power. Contactors are used when no overload protection is necessary, and at lower levels of electrical current.
One of the more common approaches is to use control logic diagrams which use common symbols to represent control components. Possible to print the page to a pdf file or from your printer. Section view of 400 ampere twohigh rollout starters isolating switch open position spring loaded door interlock contactor door interlock upper compartment door type sla contactor low voltage control circuit fuses closed position isolating switch medium voltage control. The employers liability insurance association demands that, for control systems of powerdriven metalwork presses, the contacts of contactors. When the start push button is pressed, the control relay is energized, which in turn energizes the starter coil. Controls contactors and contactor assemblies mci electronics. Working of relays a contactor is also a type of relay. However, the basic difference between the relay and contactor is that the contactor. Download it today to see just how quickly you can select products and retrieve information. The essential guide of motor control and protection. Each of these terminals is jumpered and connected twice to a 4pole. Brochure r contactors control of ac and dc power circuits.
Contactors with nc poles, magnetic or mechanical latching devices on request. Control circuit of forward reverse starter electrical. Relays are used for switching of control circuits and cannot be used for power switching with relatively higher ampacity. Motor control circuits are often connected to lower voltages than the motor they control to make it safer for operators and maintenance personnel. Typical electrical drawing symbols and conventions. Find everything you need including iec and nema motor control, solid state control, control circuit components and circuit. Relay operation the operation of a control relay is similar to a contactor.