The Essentials of Automatic Transfer Switches in Electrical Systems

In the realm of electrical engineering, the importance of reliable power cannot be overstated. Automatic Transfer Switches (ATS) play a pivotal role in ensuring this reliability, acting as the linchpin in the seamless transition between power sources.

Automatic transfer switches are vital for maintaining power and ensuring safety. Craig & Derricott is a leading specialist in automatic transfer equipment, with installations throughout the UK. Their products help prevent power loss in critical facilities like hospitals, airports, data centres, shopping centres, water infrastructure, and railways.

What are automatic transfer switches?

An Automatic Transfer Switch is an electrical device that alternates a load between two sources, typically in power backup systems. It automatically shifts electrical loads from a primary power source to a backup when the primary fails, thus ensuring a continuous power supply for essential operations. For instance, in a building that receives power from the grid, an ATS will switch to a generator if the grid power fails.

Why ATS is important.

The ATS is vital in emergency power systems at crucial installations where continuous power is imperative. It monitors the voltage and frequency of the primary power source and initiates the backup generator upon detecting a power outage or significant deviation. After verifying that the generator is providing stable power, the ATS transfers the load from the utility to the generator. When the grid recovers and is stable, the ATS reverts the load to the primary source and signals the generator to shut down following a cooldown period.

Furthermore, different configurations of the transfer switch can supply power to essential circuits or entire electrical subpanels. For example, arranging the ATS for load shedding under generator power to shut down non-essential circuits like heating and cooling. There are two main types of ATS, based on their operation:

Open Transition (Break-before-Make) ATS

This popular type briefly interrupts power when transitioning between sources, disconnecting from the current source before connecting the new source, resulting in a very short power outage.

Closed Transition (Make-before-Break)

In this type, there is no interruption in power during the transfer. It connects the new power before disconnecting the old one, allowing for a seamless transition. This is crucial in applications where even a short interruption in power supply is unacceptable.

In the UK, the choice between open and closed transition ATS depends on the specific needs of the application. For applications where a momentary power interruption is manageable, open transition ATS are popular due to their cost-effectiveness and simplicity. For critical applications where power continuity is paramount, closed transition ATS are prevalent despite their higher cost and complexity.

Engineering resilience into power systems

The practical implications of incorporating an ATS into electrical systems are profound. With more copy products on the market, choosing a reputable manufacturer known for quality, reliability and support is critical. Moreover, ATS selection can come under several disparate British standards depending on the application, tripping-up the unwary.

Expert providers like Craig and Derricott have extensive experience in their applications and selections and strong channel partners like BPX. They offer great after-sales support, including availability of spare parts and technical help.

In addition to a two-year warranty, Craig & Derricott offer the service of commissioning on all Automatic Transfer Switches. This ensures the ATS is working as expected and capable of maintaining a fully operational state during its working life.

BPX: The Distribution Backbone

The role of BPX in distributing quality electrical components, including ATS units from manufacturers like Craig and Derricott, highlights the importance of reliable distribution channels in the engineering world.

BPX’s expertise in the field ensures that engineers have access to the best solutions on the market, coupled with the support necessary to implement these systems. Their partnership with Craig and Derricott exemplifies the synergy between innovation and accessibility, bringing top-tier ATS technology to a wider audience of engineering professionals.

We offer a wide range of C&D products. The ATS starts with the Mercia line of digital ATS panel switches it extends to metal enclosed standard ATS versions to single and dual bypass models and mimic. Contact our technical support.


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