Ground fault, ship - Electrician Talk - Professional Electrical Contractors Forum
CLICK HERE AND JOIN OUR COMMUNITY TODAY, IT'S FREE!
Go Back   Electrician Talk - Professional Electrical Contractors Forum > Electrical Forum > General Electrical Discussion


Reply
 
Thread Tools Display Modes
Old 05-22-2016, 01:44 PM   #1
Junior Member
 
Join Date: May 2016
Location: Western Canada
Posts: 3
Rewards Points: 6
Default Ground fault, ship

Two generators running in parallel, had several brownouts: some shut down circuits activated, lights in and out emergency switchboard changed over to E/G. It happened several times within an hour and was noticed that the main switchboard ground fault indicating lights showed a ground fault when it occurred. Later it was found an air compressor had an exposed wire intermittently touching the metal junction box. Also when one of the gen. was on line by itself only, the MSB ground fault indicating lights also indicated a very slight ground fault, almost unnoticeable when in parallel with others. Compressor ground fault corrected. It took a while to trouble shoot the one on the gen. Finally it was found that the gen. had a faulty suppressor (I don't have the detail yet).

Not like some other vessels that I had worked before, there are no drawings for the starter panels (MCC). I remember working on some ship that a similar ground fault did trip the breaker of the equipment which was not an essential one, to protect the upstream equipment and thus the electrical plant (selective timing?). I believe it is done by sensing the unbalanced voltages among the phases. It did not happen this time.

It seems there is a serious voltage drop, big enough for it to change the ESB over to the E/G.

Not sure if the generator's suppressor fault was a pre-existing one or it was caused by the air compressor ground fault. I would imagine there is some difference if the ground faults are of the same phase or on different phases. Is it possible that it is a pre-existing condition but by itself the plant is OK, only when there is another ground fault that compounds the situation causing brownout or even blackout?

Tired to google the above but not much help. Even got confused as one of the documents using the terms "insulated neutral" and "isolated system" in the same page. The good thing is that it jogs my memory that I had a short course on electrical ground protection 40 years ago (for 33kV, irrrelevant to ship's and it was beyond me), a pass time between shore leaves, but that is all I could remember.
dwong is offline   Reply With Quote
Join Contractor Talk

Join the #1 Electrician Forum Today - It's Totally Free!

ElectricianTalk.com - Are you a Professional Electrical Contractor? If so we invite you to join our community and see what it has to offer. Our site is specifically designed for you and it's the leading place for electricians to meet online. No homeowners asking DIY questions. Just fellow tradesmen who enjoy talking about their business, their trade, and anything else that comes up. No matter what your specialty is you'll find that ElectricianTalk.com is a great community to join. Best of all it's totally free!

Join ElectricianTalk.com - Click Here JOIN FOR FREE


Warning: The topics covered on this site include activities in which there exists the potential for serious injury or death. ElectricianTalk.com DOES NOT guarantee the accuracy or completeness of any information contained on this site. Always use proper safety precaution and reference reliable outside sources before attempting any construction or remodeling task!

Sponsored Links
Advertisement
 
Reply

Tags
ground fault, ship

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
installer cut off ground on SER cable cubgirl Residential Electrical Forum 43 05-21-2016 08:12 PM
Very odd ground fault on 3 phase delta Stew985 Linework 23 05-15-2016 11:58 AM
Phantom Voltage? touchtester Residential Electrical Forum 9 04-25-2016 09:20 PM
Ungrounded Delta 480 Station Service with ground reference App4DaWin General Electrical Discussion 30 04-14-2016 12:12 PM
220 vokt ground fault breaker Morg12345 General Electrical Discussion 6 02-26-2016 09:34 AM


All times are GMT -4. The time now is 09:22 AM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.1
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Our Pro Sites Network
ContractorTalk.com | DrywallTalk.com | HVACSite.com | PaintTalk.com | PlumbingZone.com | RoofingTalk.com