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How To Choose The Right ATS For Your Diesel Generator?

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ATS, also called Automatic Transfer Switch which frequently used in diesel generator.

It can ensure an uninterrupted power supply during power outages.

It automatically transfers a power supply from its primary source (city power) to a backup source (generator) when it senses a failure or outage in the primary source (city power) until utility power is restored.

ATS for diesel generator

In simple terms, an ATS automatically detects when the mains power source fails and switches to the backup generator to provide power to essential appliances and equipment.

This article will delve deeper into the functions, types, benefits, and considerations of an ATS on a generator.

The Primary Functions Of An ATS Include

Automatic Detection: The ATS continuously monitors the utility power supply and triggers the transfer switch to the generator when it detects a power outage or voltage fluctuations.

Seamless Transfer: The ATS ensures a smooth and quick transfer of power from the utility grid to the generator, minimizing downtime and preventing disruptions to connected devices.

Load Management: The ATS is capable of managing the distribution of power to different circuits or appliances, prioritizing critical loads during a power outage.

What Are The Benefits Of ATS On A Generator Installation?

ATS offers numerous benefits for residential, commercial, and industrial users, including:

Uninterrupted Power Supply: An ATS ensures a seamless transition from the utility power to the backup generator, providing uninterrupted power during outages and emergencies.

Increased Convenience: With an ATS in place, users do not have to manually switch between power sources, saving time and effort during power outages.

Protection of Appliances: The ATS helps to safeguard sensitive appliances and equipment from power surges and voltage fluctuations, ensuring their longevity and optimal performance.

Enhanced Safety: By automatically switching to the generator during power outages, an ATS prevents accidents, injuries, and fire hazards that may occur when using candles or alternative power sources.

Why Is An Automatic Transfer Switch ATS Important?

An automatic transfer switch ATS panel is important because it helps to prevent the mains power from coming into contact with the generator, which could damage the generator.

Additionally, it prevents the generator from backfeeding the mains during a failure, which could endanger the lives of electricity utility workers.

It is required necessary when installing a generator at premises with a Mains supply.

ATS Installation

How Does An Automatic Transfer Switch ATS Work?

An automatic transfer switch ATS panel works by automatically switching between the mains and generator in the event of a power failure.

There are two main types of automatic transfer switch panels: ones with built-in mains detection and ones without mains detection.

Automatic transfer switch ATS panels with mains detection monitor the mains supply and, upon detecting a mains failure, disconnect from the mains and signal the generator to start.

Once the generator is running, it sends an “available” signal back, prompting the ATS to switch to the generator supply.

Automatic transfer switch ATS panels without mains detection rely on the generator or another source to detect a mains failure.

When a failure is detected, the generator sends a signal to the ATS to disconnect from the mains and start automatically.

Once the generator is running, it sends a signal back to the ATS, which then switches to the generator supply.

ATS control box inside

What Are The Advantages Of An Automatic Transfer Switch ATS?

Advantages of an automatic transfer switch ATS

  • You don’t need to switch it every time the mains fails and you want to run the generator. It will start automatically. Even if you aren’t nearby, the generator can auto-working. Unless you remember to turn off the generator.
  • Wiring – there are no control cables needed, just the electricity supply cables.

    Do Necessary Need An ATS For A Diesel Generator?

    Almost definitely need it.

    Even if your generator only powers lighting, an automatic transfer switch drastically simplifies processes and makes your restoration of vision a matter of seconds, rather than minutes.

    There are a few situations that don’t necessarily require an automatic transfer switch. For example, many residential homes and structures don’t need one to power a refrigerator or other small appliances, though even then an automatic transfer switch adds a lot of benefits.

    High-powered appliances and equipment carry a massive load, and connections made directly without the use of an automatic transfer switch (ATS) can be extremely dangerous, incurring risks like physical harm and even electrical fires or the loss of commercial equipment.

    Is An ATS And AMF Similar In A Diesel Generator?

    Both ATS (Automatic Transfer Switch) and AMF (Automatic Mains Failure) are designed to switch the electrical load of a system from the normal supply to a standby supply and back again.

    Normally this would be from the Mains to a Generator.

    This is accomplished by the use of an electronic control module that monitors both supplies and a pair of interlocked contactors, switches, or circuit breakers that switch the supplies.

    Under most conditions the Mains is available and its contactor closed, when the Mains fails the control module sends a signal to start the generator.

    The only difference between an ATS and an AMF is how the generator is started.

    ATS – includes a volt-free contact that the generator uses to start/stop via its set-mounted control panel – GCP.

    AMF – includes a generator controller with start/stop (cranking) plus speed, oil pressure, water temperature, and fuel level alarms.

    AMF Genset Controller

    Thus if the system has a generator with its own Generator Control Panel (GCP) then an ATS is suitable.

    They are also suitable for switching from Mains to Mains supplies.

    If the standby supply is from a generator without its own Generator Control Panel (GCP) then an AMF is required

    What Are The Ampere Ratings For ATS Used In Diesel Generators?

    Automatic transfer switches for diesel generators are manufactured to meet continuous current ratings of 40-4000 amperes.

    Typically, the most commonly used ampere ratings include 40, 63, 80, 100, 125, 160, 200, 250, 300, 400, 630, 800, 1000, 1250, 1600, 2000, 2500, 3000 and 4000 amperes.

    ATS Amperes

    How Far Can A Diesel Generator Be From The Automatic Transfer Switch ATS?

    Usually is 18 to 21 meters between the generator and the automatic transfer switch ATS.

    This cuts down on generator noise. It also increases efficiency, since electricity weakens over distance.

    Do Need To Turn Off The Main Breaker When Running A Diesel Generator On An Automatic Transfer Switch?

    If the Genset is equipped with an automatic transfer switch ATS, you don’t need to turn off the main breaker when using a generator.

    Because the ATS will automatically monitor the mains power and turn it on/off.

    But if the Genset doesn’t have ATS, it requires turning off the main breaker manual.

    What Is The Difference Between An ATS And An MTS?

    ATS: An ATS is known as switchgear, this will connect between the generator and the main supply coming in or grid supply.

    It will constantly monitor the power supply and in the event of a power cut will automatically send a signal to the generator to start up and also switch your power supply from mains/grid power to the generator supply.

    This process is taken care of with no need for human interaction and takes just seconds to complete from power-off to power-on.

    This ensures minimal disruption for the user and total peace of mind.

    We advise an ATS as the best solution for our customers as it’s easy to use and fast-reacting, this will ensure that you stay powered up with no fuss and no stress either.

    MTS: An MTS will do basically the same as ATS but as the name suggests, it’s a manual type.

    In the event of a power cut you would need to start the generator and also manually switch power supplies over on the switch gear.

    Also, it would be up to you to monitor the power supply to see when restored and switch it back on again.

    The fact that you need to start and stop it manually.


    An ATS on a generator is a vital component that provides seamless and reliable backup power during utility outages. By understanding the functions, types, benefits, and considerations of an ATS, users can make informed decisions when planning for backup power solutions for their homes or businesses. Whether it’s a residential or commercial application, an ATS on a generator offers peace of mind and ensures an uninterrupted power supply when it is needed the most.

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    Ke Wong

    Ke Wong

    Hey, I’m Ke Wong joined WALT POWER in 2011. I spent a dozen years focused on generator set & load bank technology and solutions for the power & energy industry. WALT Power is a reliable & leading manufacturer & supplier in China, as a business director, I am so proud of our knowledge is more and more popular not only for engineers, and generator distributors but also for end-users. Hope you are enjoying our article, if any questions or comments welcome to send me sales at