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    60 Hz Hum, and What it Feels Like

    Peter W.
    Peter W.

    Posts : 1397
    Join date : 2016-08-07
    Location : Melrose Park, PA

    60 Hz Hum, and What it Feels Like Empty 60 Hz Hum, and What it Feels Like

    Post by Peter W. on Fri Mar 29, 2019 10:41 am

    As an aside, I toured the Veolia Steam Plant in Philadelphia, yesterday. This plant has been in continuous operation since it opened in 1909, and is quite a remarkable place. I got to be up-close-and-personal with the equipment, including the steam and gas turbines, the boilers, pumps, controls, switchgear, powerhouse and uplink.

    Standing under the main step-up transformer (2,300 VAC to 23,000 VAC) is a truly visceral experience. Once one feels that level of "HUM", one will never mistake 60 for 120 ever again.

    Relevance:

    60 HZ hum suggests a bad or failing rectifier.
    120 HZ hum suggests bad or failing filter caps.
    50 & 100 for our Euro and Asian friends.

    Amazing amount of mechanical-feedback devices in use in these plants - it seems that VFDs and  great many "modern" grid-tie devices are simply not sufficiently reliable at these levels.

    I also looked for 4-pole, double-throw knife-switches for Dave - and they would have given them to me from the older, now moth-balled equipment. But I would have needed a winch and a fork-lift to move them. Sorry, Dave!
    deepee99
    deepee99

    Posts : 2206
    Join date : 2012-05-23
    Location : Wallace, Idaho

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    Post by deepee99 on Fri Mar 29, 2019 3:06 pm

    Peter,
    Thanks for keeping an eye out for me. I have heard 60Hz up close and personal. Grand Coulee Dam is not far from us.
    -d-
    avatar
    StevieRay

    Posts : 47
    Join date : 2009-01-09
    Age : 57
    Location : Central VA

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    Post by StevieRay on Fri Mar 29, 2019 3:21 pm

    Yep, being in an enclosed space around distribution transformers is also downright SCARY -- what if one decided to blow?  Arc Flash gear, my butt -- you might only be a dark spot left on the floor.

    I've been either working in an Industrial manufacturing facility or selling electrical and (mostly) automation goods and services since 1985.  it never ceases to amaze me at the things i see, both dangerous and enchanting -- so much and yet so little has changed through the years!!!
    deepee99
    deepee99

    Posts : 2206
    Join date : 2012-05-23
    Location : Wallace, Idaho

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    Post by deepee99 on Fri Mar 29, 2019 3:34 pm

    We went to a wind farm in southern Idaho. Our normally friendly and outgoing dog took cover near those transformers and shook like he was passing peach-pits.
    Speaking of AC (or DC for that matter), you don't fully understand the "work on live circuits with one hand behind your back" axiom until you've been nipped once.
    erhard-audio
    erhard-audio

    Posts : 180
    Join date : 2017-04-07
    Age : 61
    Location : Tucson, AZ

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    Post by erhard-audio on Fri Mar 29, 2019 4:52 pm

    in the late 70's I worked on a large dam/pump house project with ASEA, these days ABB. It was all high voltage DC motors with high voltage and high current thyristor drives, high voltage AC sub stations...heck EVERYTHING was high voltage.
    One soon learned to respect that gear and listen to it. The hair on my arms used to stand up whenever I was close to any high voltage devices, interesting and scary stuff.
    No wonder I got twitches these days...... affraid

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