When switch to Liquid Cooled motors?

To prevent the motor from overheating, this heat must be dissipated. Uncooled motors dissipate the heat into the machine housing to which they are mounted and into the surroundings via convection. Air-cooled motors have a fan that blows air onto the motor housing, thereby cooling it, motors with liquid cooling are cooled with water and glycol that flow through cooling channels in the motor.

Water cooling is a highly efficient method of transferring heat away from the motor. Cooling efficiency is maintained even at lower speeds, ideal for constant torque applications. Combining water and electricity might seem like a bad idea, but it has clear advantages compared to current models. Water cooling enables improving the power production capacity of a permanent magnet motor, thus reducing the size of the motor. Moreover, the motor is completely safe.

When to choose a Liquid Cooled motor

Liquid cooled motors carry a range of benefits over air-cooled types. Let's see all.

1. Limited Footprint

2. Higher Power Needed

3. Efficiency

4. Low Noise Emission

5. High Ambient Temperature

1. Limited Footprint

Compared to other cooling methods, electric motor power is up to 50% higher with liquid cooled models, this means that electric motors can be sized smaller, with a smaller footprint. Liquid cooled electric motors can also be installed close other components, as there's any overheating risk.

2. Higher Power Needed

Liquid cooled motors are mainly recognized for their adaptability compared to standard air-cooled motors, as they offer higher power compared to an equivalent standard motor frame size. The liquid cooling dissipates the heat achieving high power levels without overheating of the motor.

3. Efficiency

Liquid cooled motors have been designed to optimize energy efficiency, but they are also perfectly suitable for use in variable speed applications. Variable speed can generate immediate operating profits, potentially up to 50% energy savings and increased productivity as a result of improving the process and reducing machine downtime.

4. Low Noise Emission

Thanks to their limited need for external components, such as ventilation/fans, noise levels are significantly reduced compared to air-cooled motors from -10 up to -20 dB (A). The liquid-cooled technology also ensures a clean surrounding environment, as there is generally no pollution associated with airflow.

5. High Ambient Temperature

When the ambient temperature is high, air cooled and uncooled electric motors can no longer achieve optimal output because the air can no longer absorb the heat sufficiently: the result is a derating. The effectiveness of the water cooling is not contingent on the ambient temperature, and there is no loss in performance

Air Cooled vs Liquid Cooled

Let's now analyze the same electric motor model (SMAC 200-052) and let's compare it in the air and liquid cooled version.

SMAC 200-052 Air Cooled

Power	7,5 kW
Duty Cycle	S2 60
Motor Length	151 mm
Motor Weight	19 kg
Efficiency	up to 94%

SMAC 200-052 Liquid Cooled

Power	8,0 kW
Duty Cycle	S1
Motor Length	151 mm
Motor Weight	19 kg
Efficiency	up to 97%

As we can seen from above table, electric motor will maintain the same dimensions and the same weight once transformed to liquid-cooled version. However electric motor power will pass from 7,5kW S2 60 (short time duty) to 8,0kw S1 (continuous duty). Efficiency will also benefit about liquid cooling system.

Benevelli Liquid Cooled Motors Range

A huge range of liquid cooled motors it's available at Benevelli, low to high voltage with IEC, NEMA or SAE interfaces.

Type	PMAC IPM
Output Power S1	1,5 to 30kW
Voltages	24 to 600V
Protection IP	54 - 66 - 67 - 6k9k
Cooling	water - glycol
Efficiency	up to 98%

Efficiency Map

What's the solution?

Many applications want smaller, lighter, and more torque dense motors. Motors have thermal limits so one main challenge in reducing their size is better cooling. It's desired to get the same torque at a smaller size without sacrificing performance and efficiency.

Liquid Cooled Motors are the solution.