A vacuum contactor is a specially designed device that is responsible for containing electrical contacts in a closed vacuum interrupter which is also known as a vacuum bottle. A vacuum contactor enables the switching to occur quickly and breaks the action of the contacts even in rough conditions. It is primarily used in controlling the switching mechanism of a power unit.
Chint Vacuum Contactor offers an exclusive range of vacuum contractors to customers. These vacuum contactors are used in different industries and sectors to fulfill wide-ranging needs in an effective style. As their size is very compact and small, they tend to occupy very small space. Due to their space efficiency, it is well appreciated by the customers. These are widely used to control electric motors, capacitor banks, large heating units, and other electric loads. Their unique feature is that they are designed using the latest and latest technology. These contractors are famous for delivering consistent performance for a longer period.
Operating Mechanism
A contact material must be chosen that ensures the expected electrical shelf life. The material should be able to maintain its mechanical integrity, maintain a low contact resistance, and maintains its HV withstand capability. The most important is that the material should be resistant to contact welding. Additional advantage if it is a low surge material or it should resist voltage escalation. The internal design of the shielding must effectively prevent the deposit of too much metal vapor onto the internal ceramic walls for the life of the VI. The lower part must be capable of maintaining its performance for the mechanical and electrical life of the contactor.
A vacuum contactor contains a vacuum interrupter and an operating mechanism. A vacuum interrupter would work in arc extinguishing when there is passing the normal current and cutting off the working current. It cannot distinguish between overload current and short-circuit current. The vacuum contactor consists of a holding coil that has an iron core and an armature. When the iron coil is energized, the armature moves towards the coils. As a result, the contactor is closed. Whenever the iron coil is de-energized, the vacuum contactor gets disconnected. The holding coils are of primarily two types, i.e., AC and DC. The working principle is primarily based on the electromagnetic principle; whenever the magnet is red hot, it would magnetize. The contactor unit would be switched on by energizing the coil. The red-hot part of the coil attracts the movable part, but the control voltage is ON condition.
Main parts of Vacuum Contactor
A vacuum contactor consists of an insulating frame, a metal base, a driving arm, a switch, and a switch drive infused with an electromagnetic system. A vacuum switch tube consists of a lower cover, an upper cover, a ceramic tube, and metal bellows. The outer covering is made up of insulating material like porcelain to structure it into a grooved porcelain tube. There is a big creepage distance and great mechanical strength. The material is known for its heat and impact resistance. A pair of contacts are compressed in the switch tube. It is made sure that the contact material is wear-resistant and has low cutting value. This condition is very helpful in satisfying the breaking performance. It efficiently reduces the overvoltage which happens due to the blocking during breaking process. It greatly improves the shelf life of the vacuum switch tube. It is the metal bellows which move axially, resulting in the moving contact to open and close.
Applications of Vacuum Contactor
Vacuum Contactors find their use in a variety of circuits. The list is as follows:
- Typical loads which consist of motors or transformers which are small
- The load current is continuously low or moderate i.e., smaller motors or transformers
- The circuit is switched off or on multiple times in a day
- The circuit requires high tenacity, i.e., around 1,00,000 operations
- Starting voltages are lower, which is needed to diminish the starting duty and voltage variations in the system
- To continue the process, which is in concurrence with fuse replacement time.
A vacuum contactor has a strong ability to extinguish, high and low voltage resistance, high operating frequency, no arcing, compact size, lightweight with long shelf life, and maintenance cycle.
