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DC Motor Testing Facilities and Service

We take pride in offering high quality parts with detailed and accurate specifications. Our product datasheets are a result of our thorough testing procedures and as a result are the most comprehensive on the market. Below we’ve given you an insight into our test machines to demonstrate our commitment in delivering motors “On Time & To Spec”.

Coordinate Measurement Machine

Our CMM measures our motors with high precision. Offering a maximum resolution of 0.02mm, even our smallest motors can be accurately profiled.

  • Coordinate Measurement Machine
  • Coordinate Measurement Machine

During the test, the CMM takes a series of pictures after the limits are entered by the operator. Once complete it stitches the pictures together to build a model, from which we are able to check the dimensions of the motor.

The results from the measurements are checked against the limits on our datasheets to ensure the motors conform to specifications. See the Product Dimensional Specification for an example of the high level of detail we provide.

Torque Testing

Built for analysing our DC motors and gearmotors, the torque machine allows us to profile the motor’s behaviour over a variety of loads.

  • Torque Testing Machine
  • Torque Testing Machine

The unit under test (UUT) is attached to an electro-fluid brake, which in turn is attached to a torque sensor. Driving the motor at its rated voltage, we can then slowly increase the voltage on the brake to measure performance at increasing loads. We note the motor’s speed, torque and current draw between no load and when the motor can no longer turn (stall).

The results are used to ensure the part meets specification, and are also used throughout our datasheets as Typical Characteristics values. Most notably, these results help us calculate the motor’s output power and efficiency which are then plotted beside the current and speed over a range of torque. This graph is shown on our product pages and datasheets as Typical DC (Gear) Motor Performance Characteristics.

Commutation Profile Test

This is an important test for checking the motor meets its construction specifications and can spot defects or problems with the motor commutator mechanism.

  • Commutation Profile Machine
  • Commutation Profile Machine

The shaft of the UUT is connected to, and driven by, a separate stepper motor. The stepper motor has over 800 steps per revolution, and at each step we measure the inductance and resistance between the terminals.

From the results we can build a complete 360° profile of the motor to check values such as Maximum Terminal Resistance as well as a variety of Typical Characteristics. We don’t normally include the results graph from this test in our datasheets, but if you are interested you can see an example in the DC Motor Commutator Profile section on this page of our datasheet help guide.

Vibration / Resonator Sled Test

Our vibration and resonator sleds are used exclusively on our vibration motors and linear resonant actuators to provide important information about vibration strengths, frequencies and other characteristics.

  • Vibration / Resonator Sled
  • Vibration / Resonator Sled

The vibrating motor is attached to a 100g sled, which is suspended by silicon bands (for a better damping factor). The sled also has a PCB which supplies the motor with power, and includes an accelerometer. Over a range of voltages we are then able to measure the motor’s vibration strength and frequency, in addition to the current draw. We can also measure the dynamic response times (lag, rise, and stop) for haptic applications.

The process is the exact same for the vibration motors and LRAs, with the exception that the LRAs are driven with a sinusoidal wave at their specified resonant frequency. They also have an additional test where the voltage is fixed at their rated voltage and the frequency is swept from 0 Hz to 250 Hz as the vibration strength is measured.

The results are used in a number of ways, but most notably in the Typical Vibration Motor / LRA Performance Characteristics graph found at the start of our datasheets and product webpages. In addition to the graphs, we can use the measured results to calculate other values, and include all of these throughout the datasheets to check conformity or to build typical characteristic profiles for the motors.

Longevity Test

Motor lifetime is a key factor for some applications and our longevity test machine can test up to 48 motors at once. This test currently only supports our vibration motors.

  • Longevity Test Machine
  • Longevity Test Machine

With 48 sleds on a long PCB each housing one motor, half are turned on for two seconds then off for two seconds. The other half compliment the first, staying off for two seconds then turning on for two seconds ensuring that there are always 24 motors turning. Each sled also has an accelerometer attached so we can tell when the motor fails, accurate to within 4 seconds. Each test batch runs for 720 hours, which means getting results take a long time!

As this is our newest machine, we are still in the process of collating results through our product line. We will be able to provide figures for standard lifetime values such as Mean Time To Failure (MTTF) and Failures In Time (FIT) in due course, check the product's datasheet for more information.

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