The Electrical Contractor Network

ECN Electrical Forum
Discussion Forums for Electricians, Inspectors and Related Professionals

Books, Tools and Test Equipment for Electrical and Construction Trades

Register Now!

Register Now!

We want your input!

Featured:
   

2017 NEC and Related
2017 NEC
Now Available!

   
Recent Posts
Sprinklered equipment 26-008
by bigpapa
12/02/16 04:24 PM
On Delay Relay with Auto Reset
by Potseal
12/01/16 09:59 AM
Wow, that was close!
by jraef
11/28/16 07:06 PM
Earthquake in New Zeeland
by RODALCO
11/27/16 11:25 PM
Calling all Non-US members!! (Non-US only)
by Tjia1981
11/27/16 06:33 AM
New in the Gallery:
12.5A through 0.75mm˛ flex (just out of curiosity)
Shout Box

Top Posters (30 Days)
gfretwell 13
HotLine1 9
Texas_Ranger 8
Trumpy 8
sparkyinak 7
Who's Online
0 registered (), 81 Guests and 4 Spiders online.
Key: Admin, Global Mod, Mod
Page 1 of 2 1 2 >
Topic Options
Rate This Topic
#69960 - 09/26/06 11:12 AM back up generators
jersey Offline
Member

Registered: 02/19/05
Posts: 13
Loc: Hopatcong N.J. 07843
I am installing a 35 kw generator to backup a 70 amp 3 phase sub panel. My question is if the building has a delta high leg service, will this effect the generator?

Top
Work Gear for Electricians and the Trades

Work Gear for Electricians and the Trades
Work Gear for Electricians and the Trades
Arc Flash Clothing, Gloves, KneePads, Tool Belts, Pouches, Tool Carriers, etc. etc....

#69961 - 09/26/06 11:34 AM Re: back up generators
LarryC Offline
Member

Registered: 07/05/04
Posts: 776
Loc: Winchester, NH, US
ASSume voltage is 120/240 center tapped delta.

What are the loads on the sub panel? All single phase, all 3 phase, or mixed? If mixed, can the generator supply them, or are you going to use a transformer? Remember the issues with SDS and grounding through transfer switches.

Top
#69962 - 09/26/06 12:27 PM Re: back up generators
jersey Offline
Member

Registered: 02/19/05
Posts: 13
Loc: Hopatcong N.J. 07843
With the 3-3 phase refridgerator units and single phase 240v water pump each leg was drawing around 31 amps apiece. Thera are other small loads.

Top
#69963 - 09/26/06 12:34 PM Re: back up generators
resqcapt19 Offline
Member

Registered: 11/10/00
Posts: 2209
Loc: IL
Can you get a generator that will supply 120/240 3 phase 4 wire?
Don
_________________________
Don(resqcapt19)

Top
#69964 - 09/29/06 07:06 AM Re: back up generators
jersey Offline
Member

Registered: 02/19/05
Posts: 13
Loc: Hopatcong N.J. 07843
the guardian type. They make 3 phase generators

Top
#69965 - 09/29/06 07:33 AM Re: back up generators
resqcapt19 Offline
Member

Registered: 11/10/00
Posts: 2209
Loc: IL
jersy,
 Quote:
the guardian type. They make 3 phase generators

They are all 3 phase wye connected units. That is not the same as a 3 phase delta system with a high leg. I have never seen a generator that could be connected 3 phase delta with a high leg. I have only seen that configeration on transformers.
Don
_________________________
Don(resqcapt19)

Top
#69966 - 09/29/06 10:40 AM Re: back up generators
LarryC Offline
Member

Registered: 07/05/04
Posts: 776
Loc: Winchester, NH, US
When I repaired generators many years ago, the small gennys on reefer trucks were 3 phase 240 delta. I don't know if they where available in anything larger than 5 or 10 KW.

If the Guardian you are talking about has a 12 lead alternator, you could rewire it for 120/240 delta with a high leg. I would check with the factory about the maximum unbalanced load.

Larry

Top
#69967 - 09/30/06 07:11 AM Re: back up generators
resqcapt19 Offline
Member

Registered: 11/10/00
Posts: 2209
Loc: IL
Larry,
 Quote:
If the Guardian you are talking about has a 12 lead alternator, you could rewire it for 120/240 delta with a high leg.

I didn't look at all of the wiring diagrams, but on the ones that I did look at, the center of the wye was an internal connection.
Don
_________________________
Don(resqcapt19)

Top
#69968 - 10/05/06 07:52 AM Re: back up generators
jersey Offline
Member

Registered: 02/19/05
Posts: 13
Loc: Hopatcong N.J. 07843
Just talked to guardian . There 3 phase units not compatible with a delta system. I have a meat packing plant that needs emergency back-up . Power always goes out they dont want there meat to go bad. Is ther an other way to go?

Top
#69969 - 10/05/06 08:04 AM Re: back up generators
jersey Offline
Member

Registered: 02/19/05
Posts: 13
Loc: Hopatcong N.J. 07843
one more question , Why would it matter if the back-up generator Was a wye ? The equipment would work 3 phase, delta or wye connected

Top
Page 1 of 2 1 2 >



ECN Electrical Forums - sponsored by Electrical Contractor Network - Electrical and Code Related Discussion for Electrical Contractors, Electricians, Inspectors, Instructors, Engineers and other related Professionals