SOLUTIONS - Moeller Electric Parts

Hot StoneNZM protects and monitors pizza ovensFreiberger Lebensmittel is a company that operates two electrical stone ovens for its pizza production atits Berlin plant. The essential components of these ovens are NZM series circuit-breakers from Moeller.These are intelligent switching devices that integrate a wide range of electronic components and arecommunication enabled via the Data Management Interface (DMI). Thanks to the DMI, NZM circuitbreakerscan be parameterised, switched and monitored remotely. The diagnostics information simplifiespreventative maintenance and allows faster troubleshooting in the event of a fault.24Electrically heated continuous feed ovensnaturally have a high current requirementand with the pizza ovens used at Freibergerthis is P = 450 kW. This corresponds to themotor rating of a V12 combustion engine withover 600 HP. The power is supplied from two1250 kVA low-voltage transformers that areconnected in parallel and have a short-circuitlevel of approx. 60 kA. Two NZM3 630A circuitbreakerswith a 150 kA short-circuit breakingcapacity are used for switching off this kind ofpower rating safely in the event of a fault. Themaximum rated current must be set exactly sothat immediate disconnection is possible in theevent of an overload caused by a fault, in orderto ensure optimum protection of the operatingpersonnel and the ovens.The rated current of the oven primarily dependson the amount of dough mix to be heated, i.e.the number of pizzas in the oven, as well asthe required feeding speed and the number ofbaking shelves. In the event of a short-circuit, thecircuit-breaker must be able to disconnect thepizza oven in 0.04 s.Configurable protective functionThe circuit-breakers of Moeller‘s new NZMseries guide the power to the connected loadsand disconnect them reliably in the event ofoverloads or short-circuits. They can be used forsystem and cable protection, motor protection,or selective and generator protection. The releaseelectronics unit forms the core of every NZM,and is used to not only detect the actual currentsquickly but also to evaluate them at the sametime. The circuit-breakers disconnect reliably ifthe adjustable release thresholds are exceeded.This prevents damage to machines or plants. Inpower distribution systems, incoming circuitbreakersand several outgoer circuit-breakersare arranged hierarchically and their parametersmatched up selectively so that unaffected sectionsof the system can continue to operate withoutany interruption. Circuit-breaker parameters canbe shown graphically in the form of trippingcharacteristics for optimum setting, thussimplifying commissioning.Preventing downtimes and managing powerefficientlyThe release electronics unit derives importantoperating and diagnostics data from the actualFor Moeller Electric Sales and Support call KMparts.com (866) 595-9616