[Sneap] sparking problem

[spencer trimble]

I had a problem at Fla State Univ. FN where a spark was getting into the 20 HP drive motor and traveling thru the shielded power leads to the tank feed thru where the spark would destroy the feed thru on the outside of the tank.
The final solution was to put copper screen wire over the motor cooling entrances, as that was where the spark was entering the motor. Don't know if your motors are air (gas) cooled, but if they are this worked for me.
Good luck,
Spencer Trimble
FSU RETIRED



From: ahaberl at albany.eduTo: sneap at tunl.duke.eduDate: Mon, 2 Feb 2009 10:14:27 -0500Subject: Re: [Sneap] sparking problem
Tom,
    Among other things, you need 250 volt MOVs to ground on every wire at the motor.  It wouldn't hurt to also have them at the exit from the tank.
 
    Art Haberl
 

----- Original Message ----- 
From: Miller, Thomas Edward 
To: sneap at tunl.duke.edu 
Sent: Sunday, February 01, 2009 8:34 AM
Subject: [Sneap] sparking problem










SNEAPERs:
 
I need your advice. For our 2 drive motors inside the tank we have PI filters inside a metal box in series with the 2 motors. Connections from the tank feedthrus are made with copper conduit to the box and then to the motor. It was found that spark damage inside the copper conduit between the wires and the copper conduit had damaged the wires that are between the motor and PI filter box. What was done was the PI filter box was mounted outside the tank and the conduit connecting both the PI filter box to the tank feedthrus and the tank feedthrus to the motors was replaced with plastic conduit. What this did was bring the spark energy outside the tank where it can now damage equipment outside the tank. 
 
What is your recommended solution, i.e. how have you guys done it?
 
I would like to have a better robust filtering for the motors on the inside to prevent the spark energy from getting out of the tank and a better conduit system. Seems like spark energy is traveling thru the motor 208 VAC wires and needs to be removed right at the motor. Any help would be great.
 
Thank you. Cheers!!!!
 
  Tom Miller
  Purdue University
  millerte at purdue.edu



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