Much like in electric motor performance, keeping cool is important when making the decision between air and liquid cooling. Is it worth investing in liquid cooling?  Is it time to let go of the old fan system? These are questions that are all important to consider. Here, Nicola Acampora, Head of Sales at Hyve Group, organiser of CWIEME Berlin, provides a comparative evaluation of electric motor cooling systems.

The need for cool

Electric motors generate heat due to energy losses during operation — the more stress, the more the machine radiates heat that needs to be displaced. This makes it crucial to be aware of the operational temperatures and how to keep it within an optimal range. 

If unchecked, this heat can lead to short- and long-term degradation of the electric motor. Excessive heat can warp mechanical components or damage bearings, leading to immediate operational issues. There is also a significant difference in performance under “hot” conditions, meaning that finding the right cooling system for electric motors is imperative to its energy efficiency.

The longer an electric motor is subject to unproper cooling, the shorter its operational lifespan, as wear and tear will be accelerated. Prolonged exposure to high temperatures can deteriorate insulation materials, which poses a risk to both operation and safety. Without sufficient insulation material, electrical shorts can fail the entire machine, while flammable components might now be continuously exposed to high temperatures.

Is simple best?

A rotary fan is the simplest method to displace hot air surrounding an electric motor, promoting convection that allows cooler air to replace it.

An uncomplicated layout reduces the number of components and potential failure points, ensuring greater reliability and ease of troubleshooting. Installation and maintenance are also easier and cost-effective, requiring fewer resources to be committed to start and keep these systems running. A lightweight design also makes this ideal for agile or mobile tasks.

Cool, compact and consistent

Liquid cooling takes advantage of the high heat capacity in fluids like water and certain oils to absorb the heat energy emitted by electric motors. 

This can be done by funnelling the cooling system through the heat source itself or via a jacket that covers the entire component, which greatly improves the cooling efficiency. The more direct heat dissipation method also allows more control over the temperature, regulating the environment of the electric motor to a consistent level. Design flexibilities like compactness and shape are also made possible by the efficiency of liquid cooling.

Decisions, decisions…

Making the choice will often come down to each system’s limitations and challenges. 

Sticking with liquid cooling, the complexity produces a higher initial investment that might not be appropriate for smaller projects. On a similar note, higher expertise is needed to perform maintenance checks and repairs. Depending on the fluid choice, liquid cooling can also be sensitive to extreme temperatures, where there are risks of freezing or evaporation. This makes applications such as high-performance industrial machinery or electric vehicles an appropriate setting, demanding high thermal dissipation with relative environmental consistency.

Air cooling has comparatively lower performance, which might not keep up with electric motors that produce high heat intensity. If the design requires tight or enclosed spaces where air currents are harder to generate, a fan-based system will struggle. A generally hot operational environment might also make it hard to generate the necessary convection to cool down the electric motor. Its simple nature yields itself to lightweight, simple designs like portable power tools and drones.

Practical experience under application conditions is the most valuable data that can help the decision-making process, however this is not always possible especially when starting a project from scratch. To get around this, talk to industry experts and be inspired by modernised, proven solutions. The global coil winding and electrical manufacturing event, CWIEME Berlin, is a melting pot of ideas that inspires start-ups and industry leaders alike. This is an environment that facilitates conversation and idea-exchange with other professionals who would have overcome optimal operational temperature challenges.

Register your interest in CWIEME Berlin 2026, taking place from 19-21 May 2026, connecting the leading coil winding and electrical manufacturing experts.