ELECTRICAL CONTROL PANELS- FROM BEGINNERS POINT OF VIEW For controlling the equipments, electrical control panel is used. They provide power, control, and operator devices that allow an operator for providing a piece of equipment. For controlling every piece of equipment in the industry electrical control panels are used and it is very tough for describing all the device combinations possible as every industry and the most companies have defined preferences. If you are a fresher and need to learn about the control panels fast, take your time. Find someone for helping you and someone who knows about your work. Begin from the base and build up from there. The Basics Of Control Panels The logical operating sequence is controlled by the control components. Here are major control component type descriptions: Control Relays: The simplest electrical device for control is the control relay. It has a coil that can be energized and de-energized by an electrical voltage and contacts that change logic state based on the coil state. Other devices like contactors, pilot, light, etc are turned using in Control relays for on and off purpose. Timing Relays: It is the simplest control device as they control relays with built-i timers for controlling their contacts change state and are used for switching on and off the devices like contactors, pilot lights,etc at specific times. ON TIMER– For changing to on state it has contacts after on delay when coil is energized. Off TIMER– While coil is de-energized contacts change to off state after off delay. ONE SHOT TIMER– When coil is energized it has contacts for changing and remaining in on state and on time when coil is energized. REPEAT CYCLE TIMER– There is a repeated change in states of contacts (on/off) when coil is energized.
Programmable Logic Controllers (PLC): A collection of components (relays, timers, etc) in a package is called PLC. They are packed in various forms and is varied in price from under 100 $ to several thousand dollars. They also allow communications and are very flexible with communication but you need people with good computer skills, along with programming tools, softwares, cables, computer system, etc. for getting a good properly in your application. Here are few examples for detailing some of the control panel attributes. 1) Safety Ratings certificate from the 3rd party about its safety= UL508A (cULus) Short Circuit Current Rating (SCCR)= 5kA. 2) Enclosure Ratings NEMA Rating: NEMA 4x Outdoor Material: 304 Stainless Steel Mounting: Wall Mounting Door Mechanism: Lockable Handle with 3 Point Door Latch 3) Main Power Incoming Power 480V 3 Phase through a Main Circuit Breaker Outgoing 480 V Power 480 V 3 Phase 5.0 Hp Fan through a Motor Starter 480 V 3 Phase 1.0 HP Pump through a Motor Starter. 4) Control Power •120V and 24VDC •480V-120V Transformer •120V-24VDC Power Supply •Outgoing 120V Power •Chemical Pump through a Power Relay
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