Recent content by wzhit

Last post We bought a filter and connected the ground cable with a different scheme, and now the noise is reduced by about 50%. One can't pay too much attention to ground cables. Thank you everyone for your help.

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As is well-known, mechanical vibrations and electrical currents can introduce noise. To avoid the mechanical vibrations, I took the load cell away from the motor(in fact, it is a thrust), say, put the load cell on the ground. For sure there is no load. To keep the electical current there, I used...

I found the noise in the output of both the load cell and displacement sensor. See the previous post: When the load cell is put on the ground and is connected to the motor via a cable, the noise is there; if disconnecting the cable, the noise disappears. It clearly shows the noise is...

Now, the question is: if all the motors, or PM AC synchronous motors, have the low frequency noise. I mean firstly I want to know if it is possible to solve the problem for me. Maybe it is a general problem, and I can do nothing. Thanks to everyone.

This idea is very interesting,haha. I'm to consider it.

My replies: I measure the displacement and force via displacement transducers and load cells. The signals have been shown by a scope, and the noise is there. The noise is introduced by the running motor. It has something to do with electricity or EM field. The same thanks to you!

I try to response to your reply. 1 I tried to use a Meta System power supply for all the devices except the motor. This indicates two ground cables are connected, one for the motor and the other for all other devices. However, the results didn't change better. 2 As for an isolation...

Good questions! I forgot to mention this. First, it is not the vibration of the specimen. When the load cell is put on the ground and is connected to the motor via a cable, the noise is there; if disconnecting the cable, the noise disappears. It clearly shows the noise is due to the EM...

Thanks for your reply. AC=50Hz, RPM=3000 I know less about the mechanics of the PMSM, and can you explain more why there should be not any noise less than 10Hz?

I am using an electric motor to impose displacements on a specimen, but when the motor is on, there is too much noise in the displacement and force signal. Everything seems to be nice when the motor is off. The frequencies of the noise are less than 10Hz, too low to be filtered. In...