A new push for enclosure climatisation


he small compact thermostats KTO 111 and KTS 111 from STEGO feature a practical innovation: Push-In terminals ensure faster and tool-free connection. The small-sized regulators can be quickly connected within an enclosure or control cabinet to switch heating and cooling systems. These provide a constant climate, prevent the formation of harmful condensation, and enable trouble-free operation of sensitive electronics. With the new KTO / KTS thermostats, STEGO has taken the opportunity to adapt its regulators to meet the requirements of the enclosure manufacturing industry. KTO 111 and KTS 111 connect to the power supply tool-free using Push-In terminals on the front of the housing. The terminals provide constant pressure on the connection wires ensuring safety even during transportation of preassembled enclosures. It prevents wires from becoming loosened. Another advantage of the Push-In terminals is a 2/3rd reduction of installation time due to tool-free wiring.

NC and NO Contacts for optimal climate

The mechanical thermostat may appear to be small and possibly unspectacular but thermostats are important components in every enclosure. They regulate the

climatisation of electronic components within the desired temperature range and thus help protect against harmful condensation. The two new thermostats are designed as two-state regulators with a sensor element made of thermostatic bimetal. The flexible bimetal bends under the influence of temperature and switches a snap-action contact. The KTO 111 is a contact breaker (NC – normally closed - the contact opens when the temperature is rising) for regulating heaters. The KTS 111 is a contact maker (NO – normally open, the contact closes when the temperature is rising) for regulating filter fans, heat exchangers, cooling appliances, or switching signal devices. So, what is the advantage of using a thermostat duo over a thermostat with change-over contact? The combination of two single thermostats (NC and NO) is more economical and allows the user to individually set the temperature ranges for heating and cooling. On the other hand, the change-over contact provides a specific changing point between heating and cooling and is a good choice when space is at a premium. The Schwaebisch Hall, Germany-based company has put a lot of effort into the re-design of the thermostat housing. Now the thermostat has “more air to breathe”. Enlarged air gaps on the rear of the thermostat housing ensure an optimised air intake and

thus improved response time to temperature changes. Noticeable is also the curved, ergonomic housing design on the front with a large setting dial, which is easier to read and increases safety against unintentional adjustments: the

temperature setting can only be changed with a screwdriver.

STEGO´s head of development Peter Witsch points out the company’s special relationship to the enclosure and cabinet thermostat: “Our company co-founder and former head of development Hartmut Eisenhauer developed the bimetal thermostat for enclosures and control cabinets around 30 years ago. Since then, this product invention has become an established industry product. Therefore, we are committed to further extend the product benefits for customers with each re-design.”

Tried and tested in harsh environments

The operating temperature of the thermostats ranges from -45 to +80 °C (-49 to + 176 °F) in an environment with a maximum of 90 per cent relative humidity (non-condensing).

KTO / KTS are developed for protection type IP20 and protection class 2, achieve a verified service life of 100,000 cycles, and are suitable for the following switching currents: AC 250 V, AC 120 V, and DC 24 to 72 V. The maximum inrush current is AC 16 A for 10 seconds. The switch temperature difference is 7 K with a tolerance of ±4 K. They are mounted by the clip for a DIN rail. A special feature of the new thermostats is their suitability for use in high altitudes. The thermostats can be used up to 5,000 meters (in overvoltage category II) and up to 2,000 meters (in overvoltage category III), thanks to the optimised air gap and increased creepage distance. The thermostats KTO 111 and KTS 111 have standard agency approvals, such as safety approvals by UL and VDE. Aluminium enclosures for gas analysis electronics M

etcase’s portable instrument enclosures and 19” rack cases have become increasingly popular with electronics engineers

designing new gas analysis equipment. A key reason is that the enclosures can be ordered fully modified, ready for the production line. These stylish, robust aluminium enclosures are also ideal for other applications including networking, laboratory instrumentation, industrial control, sound and studio electronics, medical and wellness applications. COMBIMET 19” is Metcase’s most customisable and cost-effective range of standard 19” rack cases. The top, base and rear panels are removable. Both the top

22 July/August 2021

and base can be specified with or without ventilation. The large range of standard options includes heights from 1U to 6U. Three standard depths include extra-deep (610 mm) cases for server racks. There is also an open-top T version for optimum cooling and ease of access.

Components in Electronics

TECHNOMET 19” is the mini-rack version of Metcase’s most advanced instrument enclosures: its cohesive design has no visible fixing screws. Diecast bezels fit flush with the main case body for superior aesthetics. Each enclosure includes a removable rear panel and internal subrack/ chassis support rails. Recessed ABS side handles enable easy carrying. UNIMET and UNIMET-PLUS are smart, modern desktop instrument enclosures available with/without a tilt/swivel carrying handle that doubles as a desk stand. The handle can be adjusted to ensure the optimum viewing angle. The removable rear panel is recessed to protect connectors and switches. UNIMET-PLUS has four snap-in PCB guides, speeding up installations.

The enclosures are available in a range of standard colours including light grey (RAL 7035), black (RAL 9005) and a combination of light grey/window grey (RAL 7035/RAL 7040). Custom colours are available (with no extra cost for ‘always in stock’ colours). All four models are supplied fully assembled. A large range of accessories including PCB mounting kits, front panels and tilt feet kits is available.

As highlighted earlier, Metcase can supply all four models fully customised. Services include custom sizes, custom front panels, CNC machining, fixings and inserts, digital printing of legends and logos, painting and finishing.

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