1 year ago

MDA Technologies 2/2014

MDA Technologies 2/2014

Drive technologies The

Drive technologies The smart way of conveying liquid to highly viscose media Holger Seybold The control of mobile pumps with a drive controller offers several benefits. In addition to smart operation with smooth conveyor output control, the additional weight of a controlled gear can be dispensed with. This means a much improved handling comfort for the user. In Wertheim, Lutz Pumpen develops and produces complete systems around the refilling and bottling of liquids. The range goes from drum and container pumps to double membrane pumps and centrifugal pumps for flow rate monitors. The drum and container pumps are designed for mobile use. These eccentric screwtype pumps serve refilling and bottling of liquid substances up to highly viscose media such as syrup or adhesives. They are usually operated at the device with a simple on/ off switch. The speed and, as a consequence, the conveyed volume, is determined by the motor speed or the combination with a gear. The drive constellation used depends on the viscosity of the medium and the desired conveyor output. The following applies: The more viscous the medium to be conveyed or the higher the desired conveyor output is, the larger the motor output has to be. To cover areas of use that are as wide as possible, the pump systems by Lutz are built in a construction kit principle. This way, several pump-motor combinations are possible The pumps as such differ by flow rate and viscosity of the medium to be conveyed, while the flan- 01 The eccentric screw-typepumps for liquid to highly viscous media are controlled by a drive controller 32 MDA Technologies 2/2014

Drive technologies ge-connected motors are not only structured in compressed air and electrical motors, but are also available with different outputs. Conversion to drive controllers To meet the market requirements for speed control of the electrical motors, adjustablespeed gears have been used until now. They are, however, heavy, which clearly increases the overall weight of the pump. The higher weight and size are a disadvantage specifically in pumps for mobile use; handling is not comfortableeither. The gear also causes additional power loss. “It was time to use frequency converters” Wolfram Entzeroth, sales manager Europe at Lutz Pumpen, summarises the matter. Instead of a mechanical solution in the form of an adjustablespeed gear, the pump manufacturer wanted to offer an electronic motor control in the form of a drive controller. The specification for this was that all switchgears and controls must be directly at the device, so that the pump can still be operated independently and easily. The purchasing department reviewed many drive controllers of various manufacturers for the requirements posed that Volker Fertig and Klaus Saemann defined before the development depart- ment and finally found what it was looking for at Kostal. The drive controller of the Inveor series met all factors and are also available in 18 performance classes and 4 sizes. Due to the perfectly integratable film keyboard, the controllers can be completely operated at the device and thus can make do without switching box or any other external operating units. With the dimensions 233 × 153 × 120 mm of the size A used, the robust die-cast housing is very compact while also complying with protection type IP65. An adapter plate is used to directly install the controller to the terminal box of the rotary current motor of the pump. At the same time, the adapter plate contains a contact strip with a plug connection that simplifies the connection. The 3-phase motor can be wired to either in a star or delta circuit. Only the common power cable is used for mains connection — as before. High operating comfort The key item in the overall concept is the film keyboard at the Kostal drive controller. The buttons “Start” and “Stop” are selfexplanatory and therefore perfectly foolproof. The regular pump operation is stored in the configurable key I. The dial switch (potentiometer) controls the motor speed and thus the displacement. The key II is preset to empty the suction pipe. The motor turns backwards at a low fixed speed to convey the content of the suction pipe out downwards. This function prevents the remaining liquid still in the suction tube from spilling onto the ground after pulling out the pump. In the background, a more elaborate technology than the simple operation would suggest is working. “The Inveor controllers have an integrated soft PLC that assumes control of the motor,” says Wolfgang Beck from Kostal sales. “In addition to a minimum speed that prevents standstill of the pump, start-up ramps are programmed to implement a soft conveyor start. Additionally, depending on the motor, a motor current threshold, blockage recognition and temperature monitoring are possible.” If a safety circuit triggers, the LED of The link to the video Behind this link, you can find the video of a Lutz pump with Inveor drive controllerfrequency converter 02 The film keyboard with its simple operationis the key to use of the drive controller in mobile pumps MDA Technologies 2/2014 33


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