Electric Motor Test Bench: How to Test an Electric Motor


In this article, we unveil the journey of conceptualization, design, and realization of our portable test bench, from the point of view of a Motor Controller Manufacturer.
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The Importance of Testing Electric Motors

Electric motors are the backbone of many industrial systems. Ensuring their optimal performance is fundamental to achieving operational efficiency and robustness. Comprehensive testing, facilitated by an efficient electric motor test bench, is essential for maintaining the integrity and performance of systems based on the use of electric motors. And for us, a company that focuses on the creation of flexible and advanced motor controllers it is essential to be able to analyze the results and quality of new technologies on the field.

What is an Electric Motor Test Bench

Test benches are specialized tools designed to rigorously assess and validate the various parameters of electrical motors and controllers. These parameters encompass a wide range of crucial factors such as temperature, current, torque, speed, voltage, noise, and more. By subjecting these components to controlled and repeatable testing conditions, manufacturers can verify their performance, efficiency, and safety before they are integrated into vehicles or other applications.
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Some of the essential components included in the Electric Motor Test Bench are:
  • Motor: The motor is a machine designed to convert electric energy into mechanical energy.
  • Torque Sensor: A torque sensor measures the torque (or twisting force) applied to a rotating system. Torque sensors can provide real-time torque measurements that are essential for engine and transmission testing, power generation, and industrial automation data collecting.
  • Encoder: An encoder is a sensor that converts motion or position into an electrical signal. It can be used to determine the speed, position, or direction of the shaft. There are various types of encoders, like rotary encoders that measure the rotational position and linear encoders that measure the linear position. Encoders are commonly found in industrial controls, robotics, photographic lenses, computer input devices, and many other applications
  • Load: the load refers to the resistive element or device that simulates the operational load that a motor would experience in a real-world application. The load ensures the motor is tested under conditions that replicate its actual use. It can be a specially designed device or a general propose motor.
In the same system, we need to note the presence of the Crankshaft that connects all the elements together, the Motor Controllers that power the motor, and finally the Power Supply that powers the full system.

Key Parameter of Test Bench Testing

Conducting regular testing of electric motors provides a wealth of benefits. It ensures standard and safety measurements. Here are some of the Parameter you can collect in a test bench:
Power Factor
Noise Level
Insulation Resistance
Measurement Unit
RPM (Revolutions per Minute)
Newton-meters (Nm)
Percentage (%)
Degrees Celsius (°C)
mm/s or g
Amperes (A)
Volts (V)
Decibels (dB)
Megaohms (MΩ)
Instrument Used
Torque Sensor
Power Analyzer
Temperature Sensor
Vibration Analyzer
Power Factor Meter
Sound Level Meter
Insulation Resistance Tester
Measures the rotational speed of the motor to assess its ability to maintain or achieve specific speeds under different load conditions.
Quantifies the twisting force exerted by the motor, indicating its power and efficiency in driving mechanical systems.
Calculated by comparing the motor’s output power to its input power to evaluate energy conversion efficiency.
Monitors the motor’s operational temperature to ensure it operates within safe and optimal temperature ranges.
Measures the amplitude and frequency of vibrations to detect imbalances, misalignments, or wear that could indicate potential issues.
Assesses the electric current flowing into the motor to ensure it’s within the specified ratings and to study the motor’s electrical load handling capacity.
Measures the electrical potential difference to ensure the motor receives the correct voltage for optimal performance.
Indicates the effectiveness of electricity usage. A low power factor suggests inefficiencies in electrical power conversion.
Assesses the noise emissions of the motor during operation, ensuring it complies with environmental and safety standards.
Measures the resistance of the motor's insulation to prevent electrical failures and ensure the safety and reliability of the motor.

Why we designed our test bench

Our specially designed test bench is a precise machine that helps us check our products with the highest level of reliability. It lets us control and keep an eye on all the important and essential parameters in our controllers. Having controllers of different sizes and performances – from the smallest SOLO Pico with 8A of electric current, to the most powerful SOLO Mega, which can handle up to 120A we now can test them in various conditions, collecting and analyzing log data.

Using this high-tech equipment, we can examine all sorts of controller details, like temperature, current, how fast they spin motors, and how much power they use. Being a versatile machine, it also allows us to test a variety of motors. It comes equipped with a magnetic powder brake that lets us adjust the load, ranging from 0 to a substantial 65 Newton-meters (NM) of torque, which could be checked in real-time by the Torque sensor. We can also simulate different scenarios by using various gear ratios:

1. Such as 1:1 with a direct shaft, connecting the motor with the load (as shown in the image below)

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2. Other ratios from 1:2 to 1:3 are performed by a timing belt gear (like shown in the image below) with a maximum rotational speed of up to 7500 RPM on the motor side.
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This flexibility enables us to put our controllers through rigorous tests, mirroring real-world conditions and ensuring they perform reliably across different setups and loads. It’s a crucial part of our commitment to delivering top-notch electric products in the ever-evolving field of electrification. Safety Protocols: Safety is paramount during the testing process. Adhering to protocols and guidelines ensures not only the safety of the personnel but also the integrity of the motor and testing equipment.

Design Philosophy

The heart and soul of any effective test bench lie in its mechanical design. From the very inception of our project, we recognized that our primary objective was to create a machine that was not only versatile but also adaptable to a wide array of testing scenarios. This adaptability was paramount in the rapidly evolving landscape of electrical motors and controllers. Thus, the mechanical design became the linchpin of our vision.
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Universality Quest and The T-Slot Plate as a Solid Foundation

The central idea was to build a test bench that could seamlessly accommodate different motors, loads, and dynamic sensors. This universality was key to its purpose. We envisioned a tool that could stand the test of time, adapting effortlessly to the ever-changing demands of the industry. To establish the cornerstone of our design, we turned to the dependable T-Slot plate. This versatile and adaptable plate was chosen to serve as the foundational layer of our test bench. Its T-shaped slots provided a convenient means for effortless mounting and precise positioning of a diverse array of components. The T-Slot plate, a fixture commonly found in manufacturing and engineering applications, delivered the structural robustness and modularity essential to our project. Furthermore, we incorporated two identical mounting brackets, each featuring a symmetrical arrangement of holes with dimensions measuring 50×100 mm in the lower section. This strategic addition expanded the versatility of our design, allowing us to accommodate a wide range of dynamic structures, from straightforward shaft connections to intricate timing belt gear transmissions.
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Layers of Electrical Connectivity

Building upon the T-Slot plate, we incorporated two additional layers dedicated to electrical connections. These layers housed power supplies, control elements, connecting terminals, and other essential components required for testing. The goal was to provide a comprehensive and easily accessible interface that could handle up to 150A of electric current.
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By integrating these layers, we ensured that power distribution and control were never an afterthought. Engineers and technicians working with our test bench could easily configure the electrical connections required for their specific tests. This approach simplified the setup process, reduced downtime, and enhanced overall efficiency.

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Power and Control at Your Fingertips

The control panel of our test bench embodies the core principle of simplifying the machine control process while ensuring real-time visibility. It features an intuitive interface that uses the green lamp to indicate an active state and the red lamp to signal safety-off conditions for the AC line, providing clear and immediate feedback to operators. Additionally, a prominent safety mushroom-type button was featured on the panel, providing an immediate means to trigger a safety-off state when necessary. Moreover, the control panel is designed to offer the most effective means of adjusting the load value. Beginning with a manual potentiometer for straightforward control, it also lays the groundwork for future enhancements, as an example the integration of PLC-based logic, allowing the system to emulate automotive testing procedures and maintain a comprehensive log of the entire testing procedure, ushering in a new level of precision and automation in our testing processes.
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The Pursuit of Precision

While the mechanical design had to facilitate this precision by maintaining robustness and adaptability, the importance of precise control over parameters like current, voltage, and torque cannot be overstated in ensuring the accurate testing of our controllers.

The most potent tool for achieving this exceptional level of precision during testing is our proprietary online software named SOLO Motion Terminal. This remarkable software seamlessly integrates with the controllers, enabling us to meticulously fine-tune and closely monitor the parameters critical to our testing processes directly on a browser.

In essence, the mechanical design of our test bench represented a delicate equilibrium between versatility, accessibility, and precision. It served as the blueprint for a tool capable of meeting the demanding flexibility requirements of our company. This steadfast commitment to mechanical excellence continues to drive our endeavors in testing new motors and spearheading the development of groundbreaking products in the electrification industry.

Test Procedure and Product Performance

Evaluating the capabilities of a new motor-controller couple is a meticulous process that demands careful consideration of various parameters. Each step of our comprehensive test procedure is essential for understanding the product’s performance and ensuring its reliability. This thorough examination encompasses both electrical and thermal aspects to prevent overheating and guarantee optimal functioning. Below, we outline the key stages of this in-depth assessment:

No-Load Assessment

The initial step involves running the motor-controller couple under no-load conditions to establish a baseline, including idling current.

Progressive Load Analysis

We incrementally apply loads, step by step, to assess the system’s performance, focusing on maximum speed, torque, and current capabilities.

Steady-State Examination

Finally, we reach a steady-state condition, subjecting the motor-controller pair to its maximum rated current for an extended duration, often up to 1 or even 2 hours. This phase is critical for evaluating thermal performance and ensuring long-term reliability.

For the thermal assessment, we employ a specialized thermal camera. This camera provides us with a detailed view of the temperature distribution across the motor, load, dynamical elements, and controller, enabling us to pinpoint potential areas of concern and ensure that the product operates within safe thermal limits, even under rigorous conditions. This systematic approach enables us to uncover the full range of capabilities of our motor-controller couples and guarantees that our products operate effectively without any risk of overheating.

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After a long and dedicated journey, marked by continuous improvements, adjustments, and rigorous trials, we have reached a compact electrical test bench that exudes flexibility and prowess. One of our defining achievements was the development of a custom water cooling system, enabling our test bench to effortlessly handle the highest possible loads while maintaining peak performance. Today, we use this powerful tool that not only unveils the intricacies of critical parameters within the motor-controller system but also offers the invaluable capability to store and assess this wealth of information in a flexible and safe way. After the finalization of this test bench, it was not only used for internal tests but was used together with suppliers, eager to validate their motors, who approached us with the idea of utilizing our testing capabilities and our motor controllers for their applications.
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