What Should Be On Your ATS Maintenance Checklist?

An automatic transfer switch (ATS) is a critical component of an emergency power system. The ATS ensures critical loads maintain power by transferring to an emergency power source when the utility power falls below predetermined limits.

The ATS is sometimes called the brain of a Emergency Power System as it continuously monitors the power coming from the utility. The ATS automatically transfers power from the utility to the backup generator if power drops to selected levels.

All electrical equipment requires routine care to ensure consistent operation. However, a piece as integral as an ATS requires a particular level of care. If performed consistently, the following steps will ensure your ATS remains in peak operational condition.

  1. Ensure mechanical integrity

Look for broken, loose, or badly worn parts. Abrasions, wears, and cuts can cause deterioration of insulation and wiring. Similarly, keep an eye out for melted plastic, metal that has discolored or oxidized, or a burning odor. All of these could be signs of overheating.

Secondly, make sure the ATS is clean and unobstructed and most important the ATS is lubricated for ease of transfer. Automatic transfer switches are often found in industrial settings, meaning dust, dirt, and moisture commonly accumulate. Cleaning the ATS with a vacuum, a brush, or cloth is appropriate—compressed air or blowers are not, as they can cause debris to become lodged in the transferring mechanism.

The final step in ensuring mechanical integrity is, checking that moving or current-carrying parts are appropriately lubricated. The transfer solenoid mechanism—which transfers the power source from the utility to the generator—should be lubricated. Finally, tighten the control wires and check the main contacts, with a Infrared Camera.

  1. Check dropout & pickup

An ATS regularly monitors the voltage and frequency of its sources. As a result, several criteria exist for initiating the deployment of the ATS—beginning with dropout voltage before transferring the emergency source. If utility voltage dips below the level set by a facility, the ATS will detect an unacceptable power source and initiate power transfer to the emergency source. 

On the other hand, pickup voltage is the criteria that identify when power source is acceptable. The pickup voltage is required for the ATS to re-transfer the load back to the standard source, usually utility power. Pickup voltages are commonly set at a higher level than dropout voltages to avoid unnecessary cycling.

Both dropout and pickup voltages are calibrated depending on the unique needs of a given facility. Therefore, carefully calibrating the dropout and pickup voltages of an ATS will ensure precise operation.

  1. Calibrate timing

Unnecessarily cycling an ATS can cause wear and tear. To avoid unnecessary cycling, an ATS uses a timing delay to check the stability of a power source. Once it detects a low-Voltage situation, the ATS will monitor the power source. A low-voltage situation could be an anomaly, but it could also be ongoing. The ATS will switch to emergency power if the power source remains low after the time delay.

As with all parts of an ATS, the timing feature should be regularly tested and calibrated. Finally, check that the engine-start feature properly works to ensure an AUTO START feature is operating properly.

Trust the experts

Automatic transfer switches are complicated, dangerous pieces of electrical equipment. Specialized training is required to install, modify, and maintain an ATS safely. At EPC Electric, we follow strict safety protocols to protect the wellbeing of our technicians, our client’s personnel and property, and the general public.

We service all brands and types of emergency power systems, and our work adheres to the strict guidelines of the National Fire Protection Association (NFPA). Get in touch with us today to learn more.

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