Types of Automatic Transfer Switches and How They Work

Providing power to your home or business in the event of a power outage or other electrical problems can be useful or even critical depending on your industry. The best way to do this is to use a generator. Generators are devices that generate electricity for some amount of time using a source of fuel like natural gas in order to replace power from the city or utility plant.

What many people don’t know about generators is that they are not the only piece you need. There is another piece that must be considered called an Automatic Transfer Switch, or ATS. An ATS is a device that acts as a brain between utility and secondary power. It acts in the event of power interruption to switch over to secondary power and control the system with little or no input from you.

After reading this guide about ATS systems, you will be more prepared to understand your power needs and decide what solution is best for your business.

Understanding ATS Systems

ATS systems act as a brain between your building, utility power and the generator. They detect changes in power and act accordingly to maintain electricity for your building with the help of a generator. If utility power cuts out, the ATS will turn on your generator and switch to it. When utility power is back, it will shut down the generator and switch back to utility power automatically.

This system, besides convenience, is there to prevent even small losses of electrical power which can be devastating for your business. The ATS and generator are sized according to the needs of your building or system. Ultimately, the intelligent backup and power transfer provided by the ATS helps maintain business continuity and prevent costly or potentially deadly failures in environments such as hospitals, heavy industries or other businesses.

Types of ATS Systems

There are four types of ATS systems that can be installed depending on the needs of the building(s). All types of switches have the same ultimate goal of managing electricity in a safe and expedient way; however, each design meets different criteria and is used for different applications. The electrical power professionals at Buckeye Power Sales can help you determine exactly what type of ATS you need and how to design it for your specific needs.

  1. Open Transition ATS – The open transition switch or break before make switch is used in systems that can handle the brief interruption in power when switching between utility and local backup power. This delay is typically less than a second long but allows for a safe transfer ensuring that no utility or local employees or people around the devices are at risk. A variation of this type of ATS is called a Programmed Transition switch which pauses between utility power and generator power. This allows residual voltage in circuits to decay prior to restoring power.
  2. Closed Transition ATS – The closed transition system is used in spaces where even a brief interruption in power cannot be tolerated. This ATS has internal systems that allow for both power sources to be on simultaneously and to allow a seamless switchover that maintains safety standards. These systems are more complicated and more expensive than open transition systems.
  3. Soft Loading Transfer Switch – This switch is similar to the closed transition ATS but has the ability to adjust the amount of load it handles from situation to situation. This dynamic capability comes at an extra cost but allows businesses to have greater flexibility against more situations that may require backup power.
  4. Bypass Isolation ATS – This is the most complicated but highest capability ATS system. It is comprised of two systems typically running in parallel allowing for inspection, maintenance and testing to be performed while in use. Setups involving Bypass Isolation ATS systems are typically used in the most sensitive business spaces such as critical life support systems, telecommunications, air traffic control stations and other similar priority 1 setups.

Standards, Certifications and Regulations

Given the complexity and sensitivity of businesses that need this level of protection, there are many codes and standards that govern these devices and their use. Standby power systems can be very complex, especially when connected in parallel with utility power. Buckeye Power Sales and their highly trained staff are experts at handling the selection and sizing of ATS and generator systems.

The team at Buckeye Power Sales can help you and your business understand every regulatory and legal compliance standard such as Underwriters Laboratories, National Electric Code and National Fire Protection Association standards, not to mention all local laws on these topics.

If you need legally mandated backups systems or are interested in having the security and peace of mind that comes with power backup systems, contact Buckeye Power Sales today to make an appointment. Our highly capable staff can help you understand and work through your needs while maintaining the strictest security and legal standards in the business.

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