Electromagnetic Interference

Thread Starter

Boomer999

Joined May 2, 2013
15
Hi guys. Trying to solve a problem, and I am hoping some one on here can help me. My friend has a 3 phase milling machine and lathe in his shop. And one either one is in use, he cant use the wireless(not a cell phone) phone in his shop. I am guessing the motors are creating Electromagnetic interference. Is that correct? Or is it something else? If it is the motors creating EMI is there something that can be done to fix it?

Thanks for your help
Boomer
 

dl324

Joined Mar 30, 2015
8,866
What frequency is the wireless phone? Has he tried phones using different frequencies?
 

Alec_t

Joined Sep 17, 2013
10,354
Identifying the route the interference takes (conduction/radiation) could be helpful.
Is the phone base station powered from the same circuit that supplies the motors?
Does the phone work correctly if used in a different room while the motors are running?
 

Thread Starter

Boomer999

Joined May 2, 2013
15
Identifying the route the interference takes (conduction/radiation) could be helpful.
Is the phone base station powered from the same circuit that supplies the motors?
Does the phone work correctly if used in a different room while the motors are running?
The phone is 11o volts, so no its on a different circuit. I will have to ask him if it works in the office area. Thank you for your response.
 

Marley

Joined Apr 4, 2016
275
Do the motors in the machines use variable speed drives (VFDs or inverters) to control motor speeds? 3-phase motors don't normally create EM interference except when starting or stopping.

Does the workshop have a 3-phase supply or is there a converter?
 

Thread Starter

Boomer999

Joined May 2, 2013
15
Do the motors in the machines use variable speed drives (VFDs or inverters) to control motor speeds? 3-phase motors don't normally create EM interference except when starting or stopping.

Does the workshop have a 3-phase supply or is there a converter?
it is a 3 phase supply. power comes into a splitter box, 3 phases go out to the 3 phase panel, and then there is a single phase panel off of the splitter as well. There are no vfd on either machine. Both machines use gear boxes to adjust the speed.
Thank you for your response
 

Thread Starter

Boomer999

Joined May 2, 2013
15
Identifying the route the interference takes (conduction/radiation) could be helpful.
Is the phone base station powered from the same circuit that supplies the motors?
Does the phone work correctly if used in a different room while the motors are running?
The phone is in the office area. And it does not work in the back of the shop or the office area when either piece of equipment is being used.
 

Marley

Joined Apr 4, 2016
275
Hard to say what the cause is.

What happens if you use an AM or FM radio while the machines are working?
Try both wavebands. Tune to a fairly weak station when the machines are off. Then switch the machines on. Are the stations affected?

Are the machines properly earthed (grounded)?
 

Alec_t

Joined Sep 17, 2013
10,354
If the phone base station and the motors don't use a star (single-point) ground system then motor current could be causing voltage shifts on the base station's ground line.
 

BR-549

Joined Sep 22, 2013
4,936
Boomer,
You wouldn't happen to have a SDR radio dongle, that you could plug into the office computer, do you?
You can get one on ebay from a regional (quick) supplier for 10 - 15 bucks. 20 bucks for a high quality one.
Mine tunes, scans and displays 60 MHz to 1.2 GHz.
Extremely handy instrument for $20.
Not to mention what a great radio it is.
 
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