Delta Supply and star generator - 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


Like Tree8Likes
  • 1 Post By frenchelectrican
  • 3 Post By micromind
  • 2 Post By micromind
  • 1 Post By brian john
  • 1 Post By frenchelectrican
Reply
 
Thread Tools Display Modes
Old 03-25-2018, 08:08 PM   #1
Junior Member
 
Join Date: Mar 2018
Location: Toronto
Posts: 17
Rewards Points: 34
Default Delta Supply and star generator

Hello everyone,

I am relatively new to this field of electrical design. In my current assignment I am working on the upgrade of some old water treatment plants with new equipment. The supply coming to one of the site is delta connected (verified from local hydro). In my design I am using a transfer switch and plan to connect a backup diesel generator to it.
My question is
(1)Does it matter if generator is star connected?
(2)Other new loads would include a pump, few heaters and a SPD. Does delta supply affect them?
(3)Do I need to contact hydro and ask them to upgrade the supply to a star? since generator is already purchased.

Any help in this regard is much appreciated. Please explain in detail since I am newbie.

-haiderster
haiderster 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
 
Old 03-25-2018, 08:12 PM   #2
fertilizer distrubuter
 
Ultrafault's Avatar
 
Join Date: Dec 2012
Location: Missouri
Posts: 1,250
Rewards Points: 554
Default

what grounding configuration do you have on your delta supply?

Sent from my SM-N910P using Tapatalk
Ultrafault is offline   Reply With Quote
Old 03-25-2018, 08:27 PM   #3
Senior Member
 
brian john's Avatar
 
Join Date: Mar 2007
Location: Gilbert's Corner VA
Posts: 30,893
Rewards Points: 3,560
Default

How many leads does the generator have, reconfigure it if possible.
__________________
Ah, but I was so much older then, I'm younger than that now
brian john is online now   Reply With Quote
Sponsored Links
Advertisement
 
Old 03-25-2018, 08:56 PM   #4
Modérateur
 
frenchelectrican's Avatar
 
Join Date: Mar 2007
Location: Philippines
Posts: 8,693
Rewards Points: 21,898
Default

What size the generator it is set up what ya plan to get it? ( if you know the model number if possible )

What voltage and conferation it is on the uility side it is now ? and please make a note which type of grounding on delta system that will make the differnce on that.

The reason why I ask due myself and couple other guys posted a very good point on the system.

there are few generators that can be reconnection on the spot. and genrally it cheaper to change connection on the generator than try to redo the uility side that will really eat up time and money.
__________________
Bleu est beau.
frenchelectrican is offline   Reply With Quote
Old 03-25-2018, 09:31 PM   #5
Junior Member
 
Join Date: Mar 2018
Location: Toronto
Posts: 17
Rewards Points: 34
Default

It is a Generac 60kW SD060 generator.
At the utility side it is 600V delta and I suspect it is ungrounded as I saw ground fault detection panel with 3 lights.
For generator leads ...I am not so sure if there are 12 or less...I have to ask the supplier.

-haiderster
haiderster is offline   Reply With Quote
Old 03-25-2018, 11:29 PM   #6
Senior Member
 
Join Date: Nov 2017
Location: Massachusetts
Posts: 615
Rewards Points: 1,230
Default

Quote:
Originally Posted by haiderster View Post
It is a Generac 60kW SD060 generator.
At the utility side it is 600V delta and I suspect it is ungrounded as I saw ground fault detection panel with 3 lights.
For generator leads ...I am not so sure if there are 12 or less...I have to ask the supplier.

-haiderster
I believe its 12
bostonPedro is offline   Reply With Quote
Old 03-26-2018, 03:19 AM   #7
Modérateur
 
frenchelectrican's Avatar
 
Join Date: Mar 2007
Location: Philippines
Posts: 8,693
Rewards Points: 21,898
Default

Quote:
Originally Posted by haiderster View Post
It is a Generac 60kW SD060 generator.
At the utility side it is 600V delta and I suspect it is ungrounded as I saw ground fault detection panel with 3 lights.
For generator leads ...I am not so sure if there are 12 or less...I have to ask the supplier.

-haiderster
Quote:
Originally Posted by bostonPedro View Post
I believe its 12
If it was wired for 480Y277 or 208Y120 then yes it is common to find 12 lead but for straight 600 volts I think it come in either 6 or 12 lead.
micromind likes this.
__________________
Bleu est beau.
frenchelectrican is offline   Reply With Quote
Old 03-26-2018, 10:33 AM   #8
Bilge Rat
 
Join Date: Aug 2007
Location: Fernley, Nevada (near Reno)
Posts: 6,912
Rewards Points: 3,432
Default

If the 600 volt ∆ has 3 lights, it is not grounded. The 3 lights are a ground fault detector.

Provided that no ground fault is present (all 3 lights glow dimly), using a 347/600 star gen will work. The system doesn't care about voltage to ground, only phase to phase.

Since it sounds like a pretty simple system, before making the actual connection, de-energize the system and megger each phase to ensure that no ground faults exist. Also megger each load that is not directly connected to the main system.

Before you merger the system, you'll need to disconnect the ground fault lights.
micromind is offline   Reply With Quote
Old 03-26-2018, 10:46 AM   #9
Senior Member
 
Bird dog's Avatar
 
Join Date: Oct 2015
Location: South East US
Posts: 6,438
Rewards Points: 582
Default

Quote:
Originally Posted by micromind View Post
If the 600 volt ∆ has 3 lights, it is not grounded. The 3 lights are a ground fault detector.

Provided that no ground fault is present (all 3 lights glow dimly), using a 347/600 star gen will work. The system doesn't care about voltage to ground, only phase to phase.

Since it sounds like a pretty simple system, before making the actual connection, de-energize the system and megger each phase to ensure that no ground faults exist. Also megger each load that is not directly connected to the main system.

Before you merger the system, you'll need to disconnect the ground fault lights.
For the NEC, wouldn't you also have to make the system a corner grounded delta? (The OP is from Canada--CEC would apply)
__________________
EARTH FIRST! We'll strip-mine the other planets later.
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Popcorn munching forum observer
"The supreme art of war is to subdue the enemy without fighting." Sun Tzu
Bird dog is online now   Reply With Quote
Old 03-26-2018, 11:53 AM   #10
Modérateur
 
frenchelectrican's Avatar
 
Join Date: Mar 2007
Location: Philippines
Posts: 8,693
Rewards Points: 21,898
Default

Quote:
Originally Posted by Bird dog View Post
For the NEC, wouldn't you also have to make the system a corner grounded delta? (The OP is from Canada--CEC would apply)
Yes and no depending on the ground fault detection system is.

But if the exsting ground fault detector is working you can use it as it is., however if you plan to remove the ground fault detector system then you have to corner grounded it.
__________________
Bleu est beau.
frenchelectrican is offline   Reply With Quote
Old 03-26-2018, 12:53 PM   #11
Senior Member
 
Join Date: Nov 2008
Location: east coast
Posts: 1,925
Rewards Points: 2,302
Default

Where I work we have a transfer switch that one source is wye and the other is delta. It works OK but when checking phasing there is always a larger than normal difference between similar phases. (NA-EA, NB-EB, NC-EC). Thank goodness we had a engineer with us when we were checking it out. He did some quick calculations and said our connections were OK.
From that experience I would label the transfer switch that one source is wye and the other source is delta and that there is a voltage difference between similar phases.

LC
__________________
What tools do I need to carry? Use the NEC as your guide keep all your tools ACCESSABLE but keep your everyday tools READILY ACCESSABLE.
Lone Crapshooter is offline   Reply With Quote
Old 03-26-2018, 06:09 PM   #12
Bilge Rat
 
Join Date: Aug 2007
Location: Fernley, Nevada (near Reno)
Posts: 6,912
Rewards Points: 3,432
Default

If there are no ground faults and the ground detector is working properly, you'll measure 347 from each phase to ground with a DMM. If the meter is low impedance, it'll affect the readings.

The 2 systems will operate the same even though one is high impedance grounded and the other is solidly grounded.

It's a bit different when a ground fault exists......the utility system will give an indication while the gen, being solidly grounded will trip a breaker, blow a fuse or blow something else up.

I believe it'd be code compliant if both the utility and the gens grounding systems are compliant since only one can supply the load at any given moment.

Last edited by micromind; 03-26-2018 at 06:11 PM.
micromind is offline   Reply With Quote
Old 03-26-2018, 08:50 PM   #13
Senior Member
 
brian john's Avatar
 
Join Date: Mar 2007
Location: Gilbert's Corner VA
Posts: 30,893
Rewards Points: 3,560
Default

BUT, Would an In-Phase Monitor on an ATS would function?
micromind likes this.
__________________
Ah, but I was so much older then, I'm younger than that now
brian john is online now   Reply With Quote
Old 03-26-2018, 10:08 PM   #14
Bilge Rat
 
Join Date: Aug 2007
Location: Fernley, Nevada (near Reno)
Posts: 6,912
Rewards Points: 3,432
Default

As far as I know, the in-phase monitor in a transfer switch looks at phase to phase voltages. I've never seen one that uses phase to neutral.

That doesn't mean they don't exist, it's just that I've never seen one.
micromind is offline   Reply With Quote
Old 03-26-2018, 10:12 PM   #15
Modérateur
 
frenchelectrican's Avatar
 
Join Date: Mar 2007
Location: Philippines
Posts: 8,693
Rewards Points: 21,898
Default

Quote:
Originally Posted by brian john View Post
BUT, Would an In-Phase Monitor on an ATS would function?
Brian John .,, typically most Inphase monitor useally read phase to phase but few models do read phase to neutral ( depending on the spec and the customer request. )
micromind likes this.
__________________
Bleu est beau.
frenchelectrican is offline   Reply With Quote
Old 04-12-2018, 01:23 AM   #16
Junior Member
 
Join Date: Mar 2018
Location: Toronto
Posts: 17
Rewards Points: 34
Default

thanks everyone for the replies, ...just to summarize
- can I connect a Y generator to a transfer switch with a delta ungrounded supply connected to the other side (yes/No?) Please note I have VFD as the main load 1X25HP
-Any special consideration about the generator grounding and how would it effect during fault condition. Do I leave the neutral floating or bond it to frame. Do I provide a grounding electrode at the generator? I still need to bring the bonding conductor to the service panel to ground it there right?
-Can I use 4 pole transfer switch and treat generator as a separately derived system? Any problem with this configuration?
-Do I need to install ground fault indication lights at the main service breaker as per the code?
haiderster is offline   Reply With Quote
Reply

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



All times are GMT -4. The time now is 06:08 PM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.1
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Our Pro Sites Network
ContractorTalk.com | DrywallTalk.com | HVACSite.com | PaintTalk.com | PlumbingZone.com | RoofingTalk.com