At Schreier Industrial, our goal is to provide the best guidance and support to our customers by helping them improve maintenance programs and install new technologies that can prevent and predict issues, and provide comprehensive data about any failures in their systems. The installation of predictive technologies like ultrasonic air leak detectors or oil analysis systems all play a part in long-term improvement of the maintenance programs and overall manufacturing processes of all our customers. While implementing new technologies is one significant factor in taking steps to improving systems, adjustments to older or already in-place systems that don’t require replacement are also a key part of the services we provide. Improving your maintenance program and production systems can be as simple as the installation of a thermal overload relay in just the right place.

Thermal overload relays are a preventative maintenance measure that shuts down overheating electrical systems before damage is done to wiring, connectors, circuit boards, casing, or any other components of electronic or electromechanical assemblies. Many fabricators are beginning to standardize highly efficient thermal overload relays into electronic systems before they are integrated into a facility, but many older assemblies can benefit from the addition of relays.

Electrical systems are protected from surges by circuit breakers and fuses, but if a system begins to overheat in a temperature range with a 115% to 125% overage, the breaker or fuse is not triggered. However, this small amount of overheating can still cause significant damage to the components of any electronic or electromechanical system. To prevent this damage, thermal overload relays are key.

How Thermal Overload Relays Work

The thermal overload relay is installed at the connection point of the power source to the electronic system. Relays hold their “open” position as long as they are not exposed to overheated temperatures. Once exposed to any slight overage, they begin to melt, and the connection to power is closed.

Two types of thermal overload relays can be installed in an electrical system: solder melting point (or solder pot) relays or bimetal strip relays. Solder pot relays have soft solder points that will trip the relay to close as soon as they begin to melt. Bimetal strip relays have multiple strands of metals that have different expansions as they heat. If they are exposed to overages, they expand and warp due to the differing expansions, triggering the relay to close. Bimetal strips can also be used to analyze the exact temperature of the overage when comparing expansion rates of each metal.

Temperature overages under 125% are detected by thermal overload relays, and the system will shut down even at a minimum of 110% overage with state-of-the-art relays available today.

Implementing thermal overload relays into your facilities can prevent damage to your electrical systems that might otherwise be undetected until complete system failure. To learn more about installing thermal overload relay switches into your facilities, contact Schreier Industrial at (218) 402-0838 or today.