Even coolant circuits cannot do without pumps these days. In quick-charge stations for electromobility, for example, they are responsible for supplying the cooling for the plugs and charging cables and are also used for server cooling in data centers. Pumps with different operating principles are used depending on the area of application, but they have one crucial thing in common: they need high-performance electric motors capable of driving them reliably and tailored to the relevant application requirements.
The basic requirements for pump drives include maintenance-free and reliable operation, smooth and quiet running and optimum noise characteristics so as not to disturb people in the vicinity. This is particularly important for patient care and laboratory workstations, for example. Depending on the pump type and task, there are then additional requirements. For example, if the primary aim is to ensure a smooth flow of the medium, such as when supplying cooling and process water or cleaning solutions, this requires a high level of control quality for the drive speed. Pumps for filling liquids also require maximum positioning accuracy. As pump drives are often operated around the clock, energy-efficient solutions are required almost in every case.
The motors must therefore offer a high degree of efficiency over a wide speed and torque range. Some pump types also require high torques when starting up, such as peristaltic pumps when the hoses are cold, or gear pumps that are exposed to arctic temperatures and pump very thick, viscous oils. Due to the compact dimensions often required in the devices, ebm-papst’s customers are increasingly favoring low-voltage drives in industrial drive technology, as the available insulation paths are small.
In many applications, there are also EMC requirements, for example under EN 60601-1-2 for medical electrical devices. In mobile pump applications, the motor must also be suitable for battery operation, meaning it must be energy-efficient, lightweight and take up little installation space. If the environment is hot, all the drive components, including the electronics and the bearing components, must be able to withstand high temperatures over their entire service life. This is often the case when coolant is pumped, for example in quick- charge stations or for server cooling.
The right drive from the modular system
Such a wide range of requirements doesn’t make drive selection easy. To help pump manufacturers quickly find what they are looking for, ebm-papst’s modular drive system includes BLDC internal and external rotor motors with different outputs and sizes, which can be combined with various gearbox designs – including for particularly quiet operation – with many reduction stages and other attachments such as brakes and encoders (Fig. 1). There are suitable encoders with high resolution for demanding positioning tasks as well as industry-standard connection technology with plugs and pre-assembled cables.
The modular system for drives with a diameter of 42 mm (ECI-42) or 63 mm (ECI-63) allows users to customize the right solution by combining different modules (Fig. 2). Available combinations and preferred types can be delivered within 48 hours of ordering. A great deal of application expertise is involved in the development of compact, electronically commutated, brushless internal rotor motors. This makes them perfect for use as pump drives, and their users benefit from complete drive solutions from a single source. Due to their high power density, the drives are very compact, which is beneficial to the device design and often enables more compact dimensions. If required, individual adaptations over and above the standard design can also be made, for instance with regard to mechanical interfaces such as spindles and gearwheels.
Different power classes for a wide range of applications
The ECI-42 brushless, electronically commutated internal rotor motors are available with stator lengths of 20 or 40 mm. They achieve outputs from 45 to 92 watts at 110 or 220 mNm nominal torque and 4,000 rpm nominal speed. With stator lengths of 20, 40 or 60 mm, the larger ECI-63 motors cover the power range from 150 to 370 W at up to 880 mNm nominal torque and 4,000 rpm nominal speed. Their efficiency is over 90%.
The motor series have already proven their efficiency in many different pump types, in gear and rotary vane pumps as well as piston, screw spindle and peristaltic pumps (Fig. 2). Now, they also ensure safe and reliable operation in many medical devices (Fig. 3). For example, an internal rotor motor with a diameter of 63 mm is the driving force in the gear pump of a hydraulic operating table adjuster as well as in piston and spindle pumps installed in chromatography systems. The 42 mm internal rotor version is ideally suited as a peristaltic pump drive for dialysis machines in laboratories. Here, the motor has been combined with a low-noise gearbox from the NoiselessPlus 42 series for ultra-quiet operation.
ebm-papst’s external rotor motors are also well suited to many pump applications. The electronically commutated VDC drives likewise operate at a high level of efficiency and meet strict EMC regulations. They lend themselves particularly well to continuous operation with very good speed consistency and have proven themselves in dialysis machines, for example, and as drives for piston pumps in systems for dissolving secretions in the case of respiratory complaints. The modular drive system also offers the right components for these motors, from the gearbox to the connection technology, so that the right drive can be found for almost any pump to meet the specific requirements profile of the application in question. In addition, ebm-papst also offers solutions for specific adaptations in consultation with customers.
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