Thermocouples and Digital Control Panels

The superiority of heaters are not defined in just by the superiority of heating elements. The real superiority is in the quality of the thermocouples and the digital control panel that accompany these heaters as well. The performance of heaters depends significantly on how accurately the temperature can be managed. As well as how precisely the controls work within the tolerance levels that the applications allow.

The control panel is responsible for the overall performance of industrial heaters and even heat distribution. The control box (also known as the terminal enclosure) contains the entire control mechanism including the digital control panel that maintains the stability of liquid contents by preventing the process of overheating deterioration of the fluid. WATTCO™ builds control panels per custom specification and its intended application, assuring the maximum efficiency and performance of the heaters.

The Type and Specification

There are generally four different types of control panels that are used on the industrial heaters:

  1. Basic control
  2. Advance control
  3. Contactor stages
  4. Base Load SCR.

The Basic control type is used for heaters that have a thermostat. It comprises of limit controlling mechanism, timers as well as additional components.

The Advance control type is appropriate for various electrical installations used with various heaters types both inside and outside. The Contactor stages type is used for multi-stage heaters that are used for heating various solutions such as water, oil, chemical, or gas. The Base Load SCR type is a step-controlling device. It is used in the Contactor stages, known as the solid-state power control.

Control panels are typically used on heaters that generate 30 to 200 Amperes. At the same time, special accommodations can be made for heaters that exceed 200 Amps, as high as 4,000 Amps watt density, equivalent to 600 Volts of power output. The design of digital control panels consist of internal wiring, switches, various fuses along with heat sensing mechanism such as thermocouples or resistance temperature detectors (RTD). The control panels are then encased within various types of housing called terminal enclosures.

The Terminal Enclosure

WATTCO™ designs the terminal enclosure using various standards defined by National Electrical Manufacturers Association (NEMA). There are three type in particular that are most common types of enclosure types: NEMA-1, NEMA-4 and NEMA-7. All of these are designed with different emphasis for use in different application types. NEMA-1 is the basic standard that is suitable for most standard non-hazardous applications.

All WATTCO™ control panels come in NEMA-1 standard or higher for that matter. Other types address various environmental concerns and are customized accordingly. NEMA-4 standard enclosures are moisture proof and provide (4x) water resistance over the standard enclosures. They are used mostly for outdoor applications protecting the device against moisture, humidity, and other extreme environmental effects using a robust technology. In many extreme cases, NEMA-7 standard enclosures are used for protection against extremely hazardous environments. It is explosion proof and therefore suitable for heating flammable chemical or gas, protecting the control panels from going haywire in case of accidents that may break out.

Ilan Toledano is the Vice President of Marketing and Sales, North America, at Wattco, a maker of electric heating elements and controls. To learn more from Wattco, call (800) 492-8826 or visit www.wattco.com.