ATS Explained: A Guide to Automatic Transfer Switches
An ATSfacilitates the continued operation of electrical systems during power outages. TheAutomatic Transfer Switch (ATS)is part of any electrical system and serves the primary function of transferring the supply of Electrical Power between two sources without manual intervention by an operator or user.
In the event of a failure or outage of the primary source of power, the ATS senses that there has been an event and transitions the supply within the user’s electrical system automatically. For example, if the commercial building or hospital has a total power loss from the utility grid, the ATS would automatically transfer the existing electrical supply for the user to the generator or backup supply of electrical power (battery backup) or alternate energy source (solar) without any manual intervention.
This event can be very seamless if there is an ATS installed in the facility; therefore protecting sensitive electronic equipment from damage, as well as providing comfort and peace of mind for users of that facility.
Objectives of Automatic Transfer Switch
The main purpose of the ATS is to ensure the electrical supply is available continuously. However, there can also be other objectives that the ATS provides. Examples of these objectives may include providing alternating voltage supplies, the continuity of electric power to various systems, reliability of electric power supply, the reduction of electrical shock hazards, and enhancement to general safety; depending on the design and construction of the ATS. It guarantees that vital electric systems continue to work during outages even if the primary power source fails, such as lights, communication systems, medical equipment or industrial settings.
Here are the primary purposes of installing an ATS in different environments:
- To provide seamless power switching/transfers in areas like hospitals, data centers and factories.
- To provide comfort and security at home during prolonged outages with backup generators.
- To ensure ready backup in applications such as with solar power systems, batteries, etc.
- To protect your equipment from sudden power loss and extended periods of power loss (downtime).
How Automatic Transfer Switches Work
The way an ATS functions is to continuously scan the status of the main source of power and switch to an alternate power source (backup) depending on availability and stability. Here’s how it happens:
1. Constantly monitors the existing main power for voltage/frequency stability. 2. When there is a disturbance (e.g., power outage, voltage drop), the ATS signals for the backup to start (e.g., generators, batteries). 3. Load is switched from the main power after backup is stable. 4. On restoration of A/C supply (main power), the load is switched back to A/C supply and the backup sources are shut off. 5. During this entire cycle there will be no gaps or delay in providing a power supply.
Types of Automatic Transfer Switches
There are a variety of automated transfer switches you can choose from depending on your needs and combination of power sources. Let’s examine some general types of Automatic Transfer Switch:
1. Open Transition ATS: The open transition ATS uses an open transition method to switch from one power source (primary) to another (secondary). The primary power source is disconnected first then the secondary power source is connected, giving a momentary interruption of electrical service. Open transitions are most commonly used in non-critical applications.
2. Closed Transition ATS: Closed transition ATS overlap (or connect) both the primary and secondary power sources (also known as a seamless switch) during the transition from one power source to another. This method of transferring the load provides uninterrupted service, making it ideal for environments that require continuous power (for example hospitals, etc.).
3. Static Transfer Switch (STS): Similar to a Closed Transition ATS, the Static Transfer Switch (STS) provides faster load transfers to a secondary power source using power electronic devices. Therefore, STS’s are extremely well suited to be utilized with extremely sensitive equipment.
4. Special Purpose ATS: ATS that are designed to accommodate alternative sources of energy, such as solar or wind; with the use of an ATS specifically designed for either solar inverters or battery back-up systems, special purpose ATS can very effectively accommodate the design of these unique types of power configurations.
What are the Key Specifications of an Automatic Transfer Switch?
When you are doing research for your new Automatic Transfer Switch, knowing your specifications for your ATS is critical to ensure that it is compatible with your power supply system. The following are the key specifications that you will need to consider:
1. Voltage Rating: Make sure that the voltage rating of your ATS matches the voltage rating of your power supply system - the most common voltage configurations are 1 phase and 3 phase.
2. Amperage Rating: Verify that the amperage rating of the ATS can support the required electrical loads in your power supply system.
3. Transition Type: Depending upon your power continuity requirements, you must determine which of the three transition types meets your needs (open, closed, or static).
4. Control Features: Most new advanced Automatic Transfer Switch units are equipped with advanced control features such as remote monitoring, manual override or independent control and programmable settings.
5. Compatibility: Make sure the ATS is compatible with your generator, battery backup, or solar energy system so that they operate at maximum efficiency.
Uses of Automatic Transfer Switches
Automatic transfer switches are deployed in numerous industrial and commercial applications. Here are some of the common areas you will see the ATS being used:
- Generators - Homeowners or commercial businesses often install a standby generator and ATS system to provide backup power when their electrical utility company has an outage.
- Renewable Energy - If you have a solar inverter or wind energy system you can install an ATS to optimize switching between the utility grid, solar energy source, as well as to your battery backup.
- Industrial Applications - Large-scale industrial facilities use ATS devices to provide stable electrical power in applications that require heavy machinery or other sensitive equipment.
- Medical Facilities - Hospitals, clinics and other medical providers use ATS to maintain ongoing operation of critical medical devices such as life-support machines during a utility power loss.
- Infrastructure for IT - Data centers are utilizing ATS equipment to prevent electrical interruptions or power loss to servers and network infrastructure; interruptions could create significant expenses.
Common Questions about Automatic Transfer Switches
What is an example of an automatic transfer switch?
A common example of an ATS can be found in residential homes that have ATSS paired with home standby generators. When there is an outage, the ATS starts the generator and transfers the electrical load from the electrical utility company to the generator. When the electrical utility company restores service, the ATS will stop the generator and transfer the load back to the electrical utility company.
What does an automatic transfer switch cost?
The price of an ATS varies due to several factors including its capacity, features, and compatibility. Basic residential ATS systems can be purchased starting at a few hundred dollars; on the other hand, ATS systems designed for industrial applications or customized ATS could be thousands of dollars.
Can I install an automatic transfer switch myself?
Installing an ATS is an electrical installation considered high voltage and it would serve you best to hire a qualified, certified electrician. Hiring a qualified, certified electrician will ensure that your installation will be completed safely and in compliance with local building codes.
Conclusion
Automatic transfer switches play an essential role in providing seamless electrical interconnection by providing maximum ease of use, maximum safety, and maximum efficiency. Automatic transfer switches are valuable so they are used to secure critical electric infrastructure, protect high-value electric equipment, and provide electric power security for residential homeowners. There are many varieties of automatic transfer switches with various applications available for purchase; however, it is up to you to determine which automatic transfer switch serves your needs. Always seek guidance from electrical professionals and make sure that you buy a quality automatic transfer switch so that your electric systems are protected.
We would love to help you explore automatic transfer switches including automatic transfer switches for generators, automatic transfer switches for solar applications, and automatic transfer switches for battery backup applications; please do not hesitate to contact us if you are interested in obtaining an automatic transfer switch.