Protection for Industrial Equipment
The fast acting magnetic operation of an E-T-A Circuit Breakers type 8340 proved to be the solution to
protect a range of plastics bending equipment.
Over the last 30 years, CR Clarke has developed an extensive range of products for fabricating plastics including local line bending, sheet heating, vacuum forming, plastic dip coating, diamond polishing and 3-dimensional colour printing.
Product development is at the heart of the organisation. As an example, the recently introduced LD range of Hot Wire Strip Heaters provide an accurate, powerful and quickly adjustable heating system for locally bending plastic materials up to 10mm in thickness. The machine comes with one double-wire doublesided
heater beam and power pack.
Thanks to the modular design, up to three additional heater beams can be added, each with an associated low voltage power tray. The LD range of strip heaters were originally fitted with simple thermally activated circuit protection. In operation, the time delay between detecting a short circuit and the power being cut could
cause damage to the heating wires. CR Clarke looked for a faster acting solution and contacted their supplier, E. Preston (Electrical) Limited, a switch and circuit protection specialist and established E-T-A
distributor.
Maurice Clarke, MD of C R Clarke, explained: “The recommended solution was an E-T-A type 8340 toggle-action, double pole circuit breaker protecting each low voltage output from the power tray. This has proved ideal as it offers very fast switching and provides two pole sensing and switching in the one component: this
enables the protection and isolation of both legs of the centre-tapped low voltage circuits used in our design, so that if either is short circuited, power is cut immediately before any damage is caused to the
heating wires.”
The E-T-A type 8340 is a very versatile circuit breaker for single up to four pole applications, with a wide choice of instantaneous magnetic or hydraulically delayed magnetic switching characteristics.
It is suitable for rail, panel or plug-in mounting in applications such as power supplies, telecommunications equipment, plant control systems and transportation. Options include auxiliary changeover contacts and a relay trip function. The type 8340 is available with current ratings from 0.02A to 50A at up to 240V AC or 80V DC.
“We knew from experience that by installing E-T-A products we were choosing circuit breakers with renowned quality and reliability, and we have been very pleased with the success of the products on our
Strip Heaters out in the field,” added Maurice Clarke.
Each Heater Beam incorporates two individually tensioned, low voltage resistance heating wires. Heating wires are fully adjustable for spacing and height, enabling materials from 1mm to 10mm to be heated. Options cater for thinner materials and for close-centre bends. The upper beams are mounted on a
hinged, spring loaded frame, allowing easy access for setting up and material loading. Beam positions are fully adjustable, with calibration strips at either end of the machine allowing quick and accurate setting. Clip-on slats support the material between the heater beams, preventing sagging between heated
regions.
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