May 20, 2021 Contactors
Contactors are used for switching an electrical circuit on or off. It is basically a special type of relay. The difference between relay and contactor is that contactor is used in applications with higher current carrying capacity. Contactor load capacity is between 9A to 1250A while relay load capacity is between 5A and 15A. Contactors are a three-phase application while relays are a single-phase application. Safety components is the contactors are spring-loaded contacts and magnetic arc suppressor. The spring-loaded contacts can prevent internal short circuit, magnetic arc suppressor on the other hand remove or reduce sparks formed when contacts carrying currents are separated. The switching speed of contactors is slower compared to relays, while relays can switch faster and can be operated using electronic signals. Contactors also consume more power than the relays. Contactors are typically used for electrical equipment that is frequently turn on and close with the opening and closing of the circuit.
When the current is switch on the current passing through the contactor will excites the electromagnet that will produces a magnetic field. The magnetic field the armature into coil allowing the normally closed (NC) contact to complete the circuit between the fixed contact and the moving contacts. This allows the current to pass through these contacts to the load. When there is no more current passing through, the coil is de-energize and the spring pushes the armature away, breaking the connection and stopping any current from passing to the load.
There are several types of contacts. The first type of contactors is knife blade switch. Knife blade switch consisted of a metal strip or blade which would drop on to a contact. It had a lever for pulling the switch down or pushing it up. The downside of knife blade switch is that the contacts wear out quickly. Besides, the operator needs to be close to it, with high current carrying switched, leading to serious safety concern.
Manual Controller is second type of contactors. Manual controller is safe to operate with no –exposed unit, all of the components are properly enclosed. The size of manual controller is typically small. Manual controller has double break contacts that open the circuit in two places at the same time. It able to work with more current and divide the connection so it forms two sets of contacts.
Third type of contactors is magnetic contactor. It does not require human intervention, operates electromechanically and operated remotely. Thus, it helps eliminate the risks involved in operating it manually and putting operating personnel in potential danger. Only a small amount of control current is required by the magnetic contactor to open or close the circuit. This is the most common type of contactor used in industrial control applications.
Contactors are available through Quick Time Engineering Inc.
Quick Time Engineering Inc is an international company with offices and distribution networks in the USA, Hong Kong, Europe and Malaysia.
In its 20 years of operation since 1998, Quick Time Engineering Inc had emerged from a local engineering company with a single staff that provided solutions in factory automation to become nowadays a company that serves the Oil & Gas industries, EPC contractors, System Integrators and other industrial automation and process control companies worldwide. Customers from over 50 countries worldwide trust us with their need for process control instruments and industrial automation products.
For more information about Quick Time Engineering Inc , visit www.quicktimeonline.com or email enquiry@quicktimeonline.com
