Switch disconnectors and motor circuit breakers
Isolation of components from energized sections of the system is the simplest (no-load) switching operation. Isolation is usually necessary for safe maintenance, repair and replacement of power system components. Only after isolation, can a person approach the relevant equipment. Frequently it could be a legal requirement to have a visible break between live and workable parts. To reduce the probability of breakdown to the absolute minimum, a very large contact distance to be achieved with the switching device, is necessary. Such switching devices are commonly called disconnectors, disconnecting switches, on/off or emergency switches and load disconnectors.
What is an on/off switch or disconnector?
Load isolation (on/off) switches or disconnectors are distribution equipment distribution equipment widely employed in factories, commercial, and industrial settings for breaking circuits, manual switching and isolating mains supply.
Often referred to as power isolators, switch disconnectors are used to disconnect electrical equipment for repair and maintenance purposes or in the event of an emergency. Especially when comes to handling highly-powered electrical equipment, it is imperative to fully discharge the electricity before initiating any repair or maintenance activities. Beyond simply cutting off the electrical flow, the disconnector also aids in the separation of various components within the electrical system.
The operating principle of a switch disconnector is straightforward. It disconnects the current or power source, facilitating easy and safe execution of maintenance, inspection and repair tasks by electricians, mechanics or technicians. These switches ensure the safety of both equipment and personnel. By minimizing the risks associated with mechanical and electrical accidents, they contribute to the establishment of a secure working environment. This is especially crucial during periods of repair and maintenance activities.
Nevertheless, the primary purpose of on/off switches is to function as emergency off-devices. Consequently, they must be readily identifiable, easily accessible and constantly visible to operators. This is why switch disconnectors feature special colours to meet the requirements of relevant electrical standards and codes.
What we have in our homes is a simple button or handle and a plug to connect an electric device to the power supply. When we push the button, press the handle or unplug the cable, the device is de-energised. Unlike residential setups where disconnecting a plug turns off electricity, industrial machines and equipment are interconnected. In many cases, one unit may need to be disconnected for repair while others continue to function normally. Consequently, a straightforward pull of the plug is not sufficient in such industrial scenarios. That’s where diconnectors come in handy. They disconnect the electricity from the appliance. Cutting the power supply ensures the workers safety and prevents possible risks of electrical shocks.
How does it work?
The main function of a switch disconnector is to disconnect the electrical power. It contains two metal plates, which separate on the opening of the switch. When the switch is closed, the contacts come together they allow the flow of electric current through the circuit. Opening and closing of Sentera’s disconnectors is done manually using the rotary knob.
Why do you need to use a switch disconnector?
Industrial machinery needs regular repairs and servicing. However, performing such activities while they are actively consuming electricity is not feasible. Consequently, switch disconnectors or power isolators come into play. These devices effectively disconnect the electricity, enabling technicians to conduct repairs safely. The widespread adoption of switch disconnectors has become a standard practice in various equipment and machinery. The greatest advantage as well as their main purpose is the protection they provide against potential damage to equipment or harm to individuals.
Poles
Just like most electrical devices, switch disconnectors come in many varieties depending on the intended use. However, the most commonly used type of disconnectors is the so called “poles”. The pole is the portion of a switching device associated exclusively with one electrically separated conducting path of its main circuit and excluding those portions which provide a means for mounting and operating all poles together. When it comes to switch disconnectors, the term "poles" means the number of circuits a switch can control. So, switch disconnectors are often equipped with poles in different capacities. Sentera offers two-pole and four-pole disconnectors used in order to meet the requirements of an electrical circuit.
How do I choose the most appropriate switch disconnector?
A vast array of switch disconnectors are currently accessible in the market, each designed to fulfill specific requirements. Therefore, when hesitating on the purchase of a switch disconnector, it is crucial to pay attention to certain essential features. Amongst these, the rated current, which an appliance or equipment can endure, is paramount. Sentera offers them within the range from 2,2 kW to 30 kW.
Sentera’s EME5 series of disconnectors offer both manual or remote to disconnection of the power lines. They are reliable and provide complete protection of both staff and equipment. In addition, some product versions can also be used for direct starting, switching off and running squirrel-cage motors.
Area of use
A switch disconnector, also known as an isolator switch, is intended for isolating power from electrical equipment connected to a circuit. This is primarily done to ensure safety and security, especially during maintenance and repair activities. Also, disconnectors break electrical circuits to halt the flow of current therefore they are extensively utilized in various industrial and factory applications. During operations, disconnectors are paired with switches, linked with earthing wires to provide additional safety to professionals dealing with intricate electrical issues or conducting maintenance and repair tasks in work areas. However, disconnectors do not control circuits; their sole function is to safely isolate power flow.
The EME5 series of switch disconnectors find applications in various industries and settings. These devices are known for their ease of installation and commissioning, high levels of safety and reliability, low maintenance requirements due to robust design and the option to be locked, thus eliminating the possibility of accidental switching on.