3 things you should know about motor alarms

By Schneider Electric | July 5, 2022

Traditional motor control protects motors in the event of an overload. Advanced motor starters provide access to data, such as running current, voltage, and status, but equipment designers often struggle with how to use this information practically. But recent innovations in motor control and protection now make it easy to monitor a much larger realm of performance issues and statuses and apply it in a practical manner.

Alarms are the key to making data more practical to realize new equipment capability. They open doors to better information, increased performance, and even more revenue. Here are three things you should know about motor alarms.

Did you know that motor current rises relative to the amount of loading on the motor? Motors are sized to perform a certain amount of work (horsepower, or HP). Thus, there is a "normal" current operating range when motors are working.

Did you know that normal loading isn't usually 100% of full load amps (FLA)? In most cases, designers typically allow some cushion when sizing motors. Also, motors tend to be most efficient when operating between 60 – 80%.

Did you know that certain conditions or issues can cause the motor current to rise or fall outside the normal range? Undercurrent can occur when the motor current is under the normal operating range. This could mean the equipment isn't being loaded up (and could be turned off to save energy), or it could mean other issues like pump cavitation, a broken conveyor belt, the compressor system needs maintenance, or it is time to replace the filter.

Overcurrent is when the motor current is higher than the normal operating range. This could mean loading is unusually high, the compressor system needs maintenance, or possibly a downstream valve is closed. A steep rise in current (called a "jam") also indicates an issue such as debris blockage or a mechanical bind.

Either way, when your motor current is operating outside of the "normal" range, you need to take action.

Having access to motor current and voltage is not new, but it's difficult to know how to use this information. Sure, a PLC program can be written to read and respond to abnormal motor current, but it's not easy to set or adjust. TeSys island motor control has solved this conundrum.

Alarms allow the programmer to easily set when a particular alarm parameter triggers a warning. For example, an undercurrent alarm can be configured in the motor starter settings to be 60% of the motor FLA.

Let's suppose an installer notices this alarm is too sensitive during commissioning. Changing the sensitivity isn't an issue with TeSys island. The undercurrent alarm setting can adjust up or down easily. Then, it can be tested again to confirm the correct sensitivity.

Alarms, instead of traditional motor controls, are capable of informing operators or maintenance teams when action is needed.

This can help end users tremendously by giving them the information to help run efficiently, increase output, and keep equipment healthy. This also allows them to manage maintenance proactively instead of reacting to unplanned downtime.

But there is another way alarms can help OEMs increase revenue, and that is through post-sale monitoring services and replacement parts. Knowledgeable maintenance staff and operators are retiring faster than they can be replaced. This technology gives OEMs an opportunity to provide more services to keep their equipment running.

Who knows the most about how to maintain a machine? The original equipment manufacturer, of course.

Motor alarms are easy to configure, adjust, and protect with TeSys island motor starters. click here to learn more.

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