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Coolant circuit secured: drives for pumps

Cooling circuits cannot do without pumps. 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. Depending on the pump type and task, there are even more 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, the drive speed must be absolutely stable. 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, such as peri­staltic pumps, also require high torques when starting up, espe­cially when the tubing is cold. Safety extra-low voltage is also often an issue because compact dimen­sions reduce the space avail­able for insu­lated sections. Many appli­ca­tions also have EMC require­ments

Figure 1: The ebm-papst modular drive system includes various BLDC internal and external rotor motors with different outputs and sizes. (Image | ebm-papst)

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, the drives must also be able to with­stand high temper­a­tures. 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 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 brakes (Fig. 1). There are suit­able encoders with high reso­lu­tion for demanding posi­tioning tasks as well as industry-stan­dard connec­tion tech­nology with plugs or 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). 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.

Figure 2: The modular drive system allows users to customize the right solu­tion by combining different modules. (Image | ebm-papst)

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.

Figure 3: The ECI/VDC motors have already proven their capa­bil­i­ties in many different types of pumps. (Image | ebm-papst)

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%. Both 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. 3). Even elec­tro­mo­bility wouldn’t be possible today without powerful pumps.

Quick-charge stations, their power elec­tronics, charging cables and any existing buffer storage need cooling concepts that can be easily inte­grated and work reli­ably over a long period of time, even under some­times very harsh envi­ron­mental condi­tions (Fig. 4).

Cooling circuit appli­ca­tion

With charging capac­i­ties of up to several hundred kilo­watts, the cables are liquid-cooled, with pumps and drives for the pumps an indis­pens­able part of the process. The internal rotor motors from the modular drive system have proven them­selves as the driving force in these appli­ca­tions over many years. One example of this is the ECI-63 internal rotor motor, which, thanks to its high power density, is typi­cally used as an effi­cient pump drive for cooling charging cables in the level 3 range with charging currents of up to 500 A (Figs. 5 and 6).

Figure 4: ebm-papst offers effi­cient pump drives for the cooling circuit and compact fans for inte­rior cooling of quick-charge stations. (Photo | ebm-papst X Midjourney)

With vari­ants in the 150 to 370 W power range, the compact drive covers a wide range of appli­ca­tions. Thanks to high-quality compo­nents, even ambient temper­a­tures of up to 80 °C are no problem for the inte­grated elec­tronics. This is why the temper­a­ture-resis­tant and reli­able ECI-63 drives, like the smaller ECI-42 vari­ants, are also used as pump drives in the cooling circuits of modern high-perfor­mance servers. However, speed/torque controlled external rotor motors from the VDC series are also ideally suited to cooling solu­tions, and addi­tion­ally enable users to make infer­ences about pres­sure and coolant flow, for example, due to their torque manage­ment.

Figure 5: Effi­cient ECI-63 pump drive for cooling charging cables. (Image | ebm-papst)

Figure 6: BLCD internal rotor drives in the ECI-63 series – here the motor char­ac­ter­istic curve with a stator length of 60 mm – can cover an output of up to 370 watts. (Image | ebm-papst)

This means addi­tional sensors are not required in the appli­ca­tion, which has a posi­tive effect on the system control of the charging station. The elec­tron­i­cally commu­tated VDC drives like­wise operate at high levels of effi­ciency and meet strict EMC regu­la­tions. The modular drive system also offers the right acces­sories 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 task in ques­tion. In addi­tion, ebm-papst also offers solu­tions for customer-specific require­ments.

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