Application
Motor & Drive Testing
Measuring input and output power, efficiency and electrical parameters on motors, drives and pumps.
Why this measurement is difficult to get right
Motor and drive testing compares electrical input against mechanical or thermal output, so efficiency is the headline result and every measurement error propagates into it. Testing a variable-frequency drive adds the complication that the waveform is neither sinusoidal nor at a constant frequency.
The practical requirement is measurement bandwidth. An instrument that averages over a period longer than the drive switching cycle will produce a stable but incorrect figure, and the error grows as the drive output becomes more distorted.
What has to be measured
- Three-phase and single-phase input power to the drive or directly to the motor.
- Output-side voltage and current where the motor is supplied from a drive.
- Power factor and frequency across the operating range, including low-speed operation.
- Winding and bearing temperature, and coolant flow where liquid cooled.
Which instrument measures what
| Quantities to measure | Instrument family |
|---|---|
| Input and output electrical power and efficiency | Digital power meters with AC/DC and multi-phase capability |
| Current measurement without breaking the circuit | Clamp meters |
| Winding and bearing temperature | Temperature measurement and transmitters |
| Coolant and lubrication flow | Flow measurement |
| Torque and speed at the shaft | Industrial sensors and load cells |
Practical considerations
- Bandwidth and sampling rate must exceed the drive switching frequency by a comfortable margin; averaging an unfiltered PWM output produces a misleading reading.
- Confirm whether the instrument supports the phase configuration in use, since three-phase measurement requires either three elements or a documented method.
- Thermal testing runs are long, so data logging and export are usually required rather than optional.
Frequently asked
Motor & Drive Testing questions
Why is bandwidth important when testing a motor drive?
A drive output is a switched waveform. If the instrument integrates over a period longer than the switching cycle it cannot capture the true RMS value of the current, so efficiency figures are systematically wrong.
Quoting for motor & drive testing
Send the measurand, the range and the conditions, and we will confirm the instrument family, the configuration and the lead time.
Request for quotation
Request a quotation - Motor & Drive Testing
Send the technical detail and we will confirm availability, lead time and terms. In-stock items ship within 48 hours; customized specifications typically take 2-10 days. Minimum order quantity is 1 pc.