How To Select An Automatic Transfer Switch (ats)

By Author: Mark Blades
Total Articles: 22
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Selecting the right generator with all its appropriate features is crucial for any standby power system. Equally important is the selection of the right automatic transfer switch for a seamless power supply. These devices are used to automatically transfer the load from the utility power source to the backup power source in scenario of a power outage. Selecting the right automatic load transfer switch requires considering various factors like the type, size, type of load, continuous current rating, voltage rating, style, compatibility, reliability, pricing etc. We look below at some of the considerations when purchasing these transfer devices.

Mode of operation

Automatic switches fall into four main types owning to their mode of operation and associated power interruption.

1.Open-Transition- These devices first open the source they are connected to and then connect to other device. Due to this, there is an interruption for a short time.

2.Fast closed-Transition- These do not open before connecting. They work by paralleling two sources first and then disconnecting the initial source when both become ...
... available.

3.Soft closed-Transition- Here the devices function by actively synchronizing the sources while transferring live sources and then connecting them together using a ramp load impulse to the backup power source.

4.Sub-Cycle Transfer- Here a slight interruption occurs between sources within the quarter of the electrical power cycle. It is predominantly used in UPS devices.

Selecting the right mode entails understanding the load required the type of application etc. For instance, a hospital would prefer switches without any power interruption since life support systems run on it. In contrast, an executive office space could probably take that few seconds of interruption.

Continuous current rating

This is the next factor to consider. The selected switch must be well capable of supplying current continuously for a minimum of 3-5 hours from the power source. Usually, the current ratings for such switches range between 30 and 400 Amps. You must ensure to match the ATS rating with that of the main breaker in the electrical control panel i.e. for a 100-amp main breaker, your ATS must also carry 100-amp.

Type of load

There are different load types like the
•Restrictive loads motor
•Total systems loads
•Electric discharge lamps and incandescent lamp roads.

Almost all generators as well as transfer switches are marked and the load type it can handle, specified. It is often recommended to opt for an ATS that can handle the total system load as it better deals with a wide range of loads.

Voltage rating

An ATS counts among those few electrical devices that can connect two unsynchronized power sources. This becomes extremely critical as the ATTS must be capable of providing adequate insulation to deal with increased voltage stress.

ATS styles

While the client may specify the style, it is available in three major styles which are –

•Standard switches- This is an old-fashioned styles in which the ATS is installed along with its sub panel. It is rarely used today and is considered an obsolete model.
•Load centers- Here the ATS and the circuit is combined as a single circuit. However, it is of limited variety as it can power only small loads of the house. It is capable of handling just 8-16 mission critical circuits simultaneously.
•Service disconnects- This ATS is ideal for larger generators that use power up to 200 Amps for any household or business requirement. It is often installed in between the electrical panel and the meter and the service entrance disconnect energizes the entire panel. While it is the costliest of the three, it is most easy and convenient to install when compared to the load center.

Conclusion

To select the most appropriate ATS for any particular situation, it is important to understand the applications as well as the client’s needs. The switch needs to be reliable as well as automatic with minimal to no interruption for all types of situations.

Blades Power Generation UK is the exclusive choice for all those looking for quality power panels, automatic transfer switches, generator switchgears, generators both old and new and all other associated products. Backed by strict quality checks, expert advice to make the right choice and the most competitive prices, our customers' satisfaction makes us thrive. Contact our expert team for more info.