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Motor control centers are usually used for low voltage three-phase alternating current motors from 208 V to 600 V. Medium-voltage motor control centers are made for large motors running at 2300 V to around 15000 V, using vacuum contactors for switching and with separate compartments for power switching and control. [3]
Also, keep in mind that ignition is based solely on the amount of natural light present and not on the height of the sun, so "unwanted ignition" may occur, for example in the presence of compact clouds associated with a significant drop in ambient light on the sensor (e.g., when there is a storm). To avoid this, twilight switches can be ...
Contacts may be operated by humans in push-buttons and switches, by mechanical pressure in sensors or machine cams, and electromechanically in relays. The surfaces where contacts touch are usually composed of metals such as silver or gold alloys [3] [4] that have high electrical conductivity, wear resistance, oxidation resistance and other ...
AC contactor for pump application. A contactor is an electrically controlled switch used for switching an electrical power circuit. [1] A contactor is typically controlled by a circuit which has a much lower power level than the switched circuit, such as a 24-volt coil electromagnet controlling a 230-volt motor switch.
In larger lighting systems, for example warehouses or outdoor lighting systems, the required current may be too high for a manual switch. In these systems light switches control lighting contactors, a relay that allows the manual light switch to operate on a lower current, with smaller wiring than would be required in the main lighting circuit.
Schematic diagram of an opto-isolator showing source of light (LED) on the left, dielectric barrier in the center, and sensor (phototransistor) on the right [note 1]. An opto-isolator (also called an optocoupler, photocoupler, or optical isolator) is an electronic component that transfers electrical signals between two isolated circuits by using light. [1]
Three photoresistors with scale in mm Large CdS photocell from a street light. A photoresistor is less light-sensitive than a photodiode or a phototransistor.The latter two components are true semiconductor devices, while a photoresistor is a passive component that does not have a PN-junction.
A lighting control system is intelligent network-based lighting control that incorporates communication between various system inputs and outputs related to lighting control with the use of one or more central computing devices. Lighting control systems are widely used on both indoor and outdoor lighting of commercial, industrial, and ...