Slip Rings for Temperature Sensing

Since 1978, Mercotac® Brushless Slip Rings have been the premiere choice for a wide range of industries and applications, including use for thermocouples signals due to their numerous advantages, such as:

• No twisted wires (so no wire breakage)
• Continuous 360° rotation capability
• Long-lasting, no maintenance
• Very low unchanging resistance
• Capability to handle power and thermocouple signals via a single, compact brushless slip ring.

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Find Which Slip Ring You Need

Thermocouples are used in many industrial applications because they accurately measure temperature. They are comprised of two dissimilar metal wires, joined at one end. This junction of metals produces a very small voltage (typically in the millivolt range) that is proportional to the temperature. Because of the incredibly low and stable resistance of the Mercotac brushless slip ring this temperature-dependent voltage can pass through the Mercotac slip ring with a negligible voltage drop or electrical noise. The voltage readings are identical on both ends of the Mercotac, so there is no change in the temperature readings. This allows for a very accurate continuous temperature measurement from a rotating shaft to the stationary meter or temperature controller.

What makes a Mercotac brushless slip ring unique is that a conductive liquid metal is used to make the rotating connection unlike a standard brushed slip ring. This eliminates the need for brushes, which because of wear and tear can cause resistance change and electrical noise that introduces errors into the measurement. The liquid metal interface has a very low resistance, which minimizes the voltage drop across the Mercotac slip ring and is stable and unchanging for the life of the slip ring.

Thermocouples are an inexpensive and reliable way to measure temperatures. They are used in manufacturing processes where the temperature control is critical. The combination of a thermocouple and a Mercotac brushless slipring can be used to measure temperatures in a wide variety of rotating applications which includes heated rolls, packaging machinery, and laminating machinery. This allows for accurate and reliable temperature monitoring, which is critical for quality, safety, and efficiency. Additionally, the use of a Mercotac product eliminates the downtime and problems associated with standard brushed slip rings.

Here are some additional details about the Mercotac brushless slipring:

• The Mercotac uses a liquid metal interface that has a high conductivity, stable connection, and a low coefficient of friction.
• The Mercotac is designed with pre-lubricated bearings, so it does not require any maintenance.
• The Mercotac is available in a variety of sizes and configurations to meet the specific requirements of each application.
• The Mercotac can be used for both power and thermocouple signals all in the same brushless slip ring.

If you are looking for a reliable and accurate way to measure temperatures in a rotating application, then a thermocouple combined with a Mercotac brushless slipring are a good option.

A Mercotac brushless slip ring typically has a maximum operating temperature of 60 degrees Celsius. Some thermocouples, on the other hand, can operate up to 2000 degrees Celsius. However, the accuracy of the thermocouple will decrease at higher temperatures.

To protect the Mercotac from the high temperatures, it is often isolated from the rotating heat source by an insulating sleeve or barrier. This allows the Mercotac to operate at its maximum temperature while still allowing the electrical signal to pass through.

The following are some ways to insulate the Mercotac from the high temperatures:

• Using a heat-insulating sleeve to mount the Mercotac made of a high-temperature material, such as high temperature plastics.
• Extend the heat-insulating sleeve and the Mercotac away from the heat source.
• Use a heat sink or active cooling to dissipate the heat away from the Mercotac.

The specific method of insulation that is used will depend on the specific application and the temperature requirements.

Here are some additional considerations when using a Mercotac brushless slipring in a high-temperature application:

• The Mercotac must be properly insulated or cooled to prevent it from overheating.
• The Mercotac must be free to rotate.

Many companies, including in the test and measurement industry, utilize Mercotac Brushless Slip Rings to make precise thermocouple temperature measurements through rotating shafts. The Mercotac brushless slip rings are an ideal solution for accurate temperature measurements on rotating mechanisms. Mercotac's low-resistance, stable connection reduces downtime, signal measurement variability, measurement drift, and uncertainty, without the need for brushes that wear out.