Electric magnet Field

Do anyone know the district you need to be from a 440 3phase electric motor


3 Comments

1HP? 50HP?

by LondonAndy - 2022-09-04 07:08:46

The age of the motor and size are relevant here - an older, poorly maintained motor might throw out more EF than a new one. 

ELECTROMAGNETIC COMPATIBILITY GUIDE

by Good Dog - 2022-09-05 10:22:27

This document while published by Medtronic should be applicable to most pacemakers:

https://www.medtronic.com/us-en/patients/electromagnetic-guide/tools-industrial.html

I must tell you that their recommendations are extremely conservative! I am sure they are written and reviewed by their lawyers! I worked my entire career on and around both induction and synchronous motors (and exciters) in sizes up to 11,000 volts and 4,000 horsepower. I always approached them cautiously, but have essentially leaned right up against them while they were running without ever experiencing an issue. I even once stood within a foot of an operating turbine generator at the Niagara Falls power plant. I would not recommend that to anyone, but my point is that I was always aware of the danger and was cautious, but I never experienced a problem. The PM manufacturer advises that if an electromagnetic field from a device or piece of equipment does negatively impact your PM and/or how you feel, that you should simply back-away from it. It is highly unlikely to cause any permanent problem.

It is always good to be cautious when in doubt.

Sincerely,

Dave

nice

by dwelch - 2022-09-07 00:07:58

Nice, thanks Dave for that link.

Not enough information about the motor to know, just dont hug it.  

I did stand near the generators at hoover damn, before I knew that was probably not a good idea.  Also visited a sub station on a field trip for college.  Learned about this stuff later when working around a shake table and management somehow decided they should worry about medical devices in visiters to find out they had an employee with one...scheduled to be in the shaker room that week (they told me not to go in, we worked with medtronic, rented a gauss meter, and I would literally have to hug the transformer when the shaker was operating in order to be within a strong enough field, and then it would just confuse the device maybe I pass out and fall away from the transformer, maybe it doesnt affect me, I didnt try). 

Also was in what they called a faraday lab next to good sized three phase and dc motors and generators for another college lab, handling cables that connected these things to each other.  Maybe a few feet away.  Also before I knew an of this.  No ill effect.  These things were I think older than my dad, not long after I graduated that equipment went into the college museum.  We did sign a release saying we understood this lab could cause death.

I dont know about todays pacers but 1 gauss Is the number I remember back then, if you can get specs on the product in question or can get your hands on a good meter (not the $20 thing that used to be advertised on this site) you can do your own measurements.  I suspect you need to get very close to the motor and then you are more likely to get hurt in other ways that can hurt everyone not just a pacer patient (sticking your hand into whatever the motor is driving, touching contacts/wires, etc).

 

 

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