Article: An Introduction to Vibration in Electric Machines

This article introduces noise and vibration in electric machines, discussing their sources and where they can be found. It will also characterize noise, vibration and harshness in electric machines, identifying some of the main features to look for and why they are important.
There will also be discussion regarding the reasons for testing both noise and vibration together; why engineers in these areas need to have knowledge of both; and why communication is key. There will also be an overview of the HBK eDrive solution.

A Simple Measurement Chain – Electric and Mechanical Vibration

The diagram above depicts an overview of the electric powertrain. There is a battery with DC electric current that goes into an inverter. This inverter switches on and off tens of thousands of times per second – it is a Pulse Width Modulation signal (PWM). This DC energy is being converted using pulse-width modulation to AC with a high frequency content.

This high frequency voltage and current then goes into a motor and creates high-frequency magnetics. These high frequency magnetics are creating high frequency torque. A lot of this gets averaged out to form DC, but if it is analyzed in detail, there is noise created by these high frequency magnetics and voltage. The chain is DC voltage to AC voltage, to magnetics, to torque and speed.

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Contact Our Expert Mitch Marks

If you have any questions concerning Electric Power Testing, we are here to support you.

Mitch Marks is among HBM's many experts in electric machine and drivetrain testing. He is a Business Developer for electrification at HBK - Hottinger, Brüel & Kjær with a Masters in electrical engineering. If you have any questions regarding our products or applications, please get in touch with Mitch.