In high ambient temperature conditions like those found in metal-heating applications, electrical enclosures need cooling units in order to enhance performance and prevent failure. The acceptable operating temperature for most electrical devices exceeds 104°F (40°C).
Typically, devices placed in cooling enclosures include variable-frequency drives (VFDs), servo drives, programmable logic controllers (PLCs), starter kits, power supplies, inverters, relays, terminal blocks, indicator lights and transformers. These systems can be protected by a cooling unit that uses either a water or water/glycol mixture. In addition to temperature, however, operators often are concerned about condensation. Moisture around electrical equipment can cause corrosion, compromise resistivity and increase the risk of short circuiting, which can lead to equipment failure.
High Temperature Processes Present Cooling Challenges. In high temperature processes involving metal heating, melting and joining, the heating equipment can take a lot of time and, therefore, use a lot of energy. In addition, the effective removal of heat — cooling — is necessary to maintain structural rigidness as well as to solidify the material in processes such as welding. Additionally, the equipment requires physical contact for frequent maintenance. Safety also is a concern with traditional welding or heating processes.
Yet, in metal heating, melting and joining applications, induction heating avoids many of the limitations of convection heating. Because it generates heat from within the object rather than transferring it via an external heat source, induction heating can use less energy. One example is automated, induction longitudinal welding, a high throughput process.
Options for Cooling Equipment Effectively. When high temperature ambient conditions exist, convection alone may not be able to adequately maintain an acceptable operational temperature. An air-cooled liquid chiller is suitable for removal of concentrated heat from process equipment, according to Pfannenberg Inc., Lancaster, N.Y.
Factors to be considered when choosing a system for cooling an induction process include cost, space availability, existing utilities, energy and water usage, equipment location, potential for freezing, level of reliability required, and maintenance.
Specific Features Can Optimize Operation. For instance, a smart controller in the cooling system can set the minimum and maximum water temperature with an alarm. In addition, a flow switch can be used to trigger an alarm if the flow is too low, protecting the equipment from being cooled. Oftentimes, the chiller can be designed with a nonferrous tank and piping to reduce corrosion. An easy-to-read fluid-level readout simplifies monitoring flow. To minimize floor space requirements, operators may want to select chillers that have a small footprint for equivalent capacity.
By using the proper temperature setting points, operators can improve performance and increase the lifetime of devices. Highly efficient cooling technologies can generate cost savings and preserve electrical equipment. Air-cooled liquid chillers are well suited for removal of concentrated heat from process equipment.