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Brush­less DC extra-low voltage drives – ideal for pump appli­ca­tions

We encounter pumps almost every­where, even if they are some­times hidden deep inside the devices. They usually convey gases or liquids. Pumps are used in addi­tive manu­fac­turing processes and perform impor­tant tasks in labo­ra­tory and medical tech­nology, for example in analyt­ical processes such as chro­matog­raphy, in dial­ysis systems and for adjusting hydraulic oper­ating tables.


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 ebm-papst modular drive system includes various BLDC internal and external rotor motors with different outputs and sizes. (Image | ebm-papst)

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

The modular drive system allows users to customize the right solu­tion by combining different modules. (Image | ebm-papst)

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.

The ECI/VDC motors have already proven their capa­bil­i­ties in many different types of pumps. (Image | ebm-papst)

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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