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
Yesterday at 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 15
HotLine1 10
Trumpy 8
Texas_Ranger 8
sparkyinak 7
Who's Online
0 registered (), 97 Guests and 5 Spiders online.
Key: Admin, Global Mod, Mod
Topic Options
Rate This Topic
#170821 - 11/12/07 05:17 PM Grounded B phase
sparky 134 Offline
Member

Registered: 09/04/04
Posts: 92
Loc: Joliet, Il, USA
I received a phone call today from an HVAC contractor who was in the process of changing out the compressor in a RTU which was fed with a grounded B phase system. He wanted to know if he could install a 3phase monitor that would prevent his compressor from running on single phase if the unit lost a phase.

I have never had the "pleasure" of working on a grounded B phase system so I didnt' have an answer for him. He said he had changed this compressor out 1.5 years ago and it had already died.

So I started thinking.....would the compressor for this type of electrical system be different from one used on a modern 3phase system ? Could the grounded B phase be the cause of the compressor failing so soon if the compressor wasn't designed for use on a grounded B phase system ?

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....

#170825 - 11/12/07 06:31 PM Re: Grounded B phase [Re: sparky 134]
gfretwell Offline

Member

Registered: 07/20/04
Posts: 9045
Loc: Estero,Fl,usa
There is nothing special about corner delta that you wouldn't have in red leg delta. Anything that works on centertapped delta should work on corner delta (except 120v loads)
He does know this is 240, not 208?
_________________________
Greg Fretwell

Top
#170827 - 11/12/07 08:13 PM Re: Grounded B phase [Re: sparky 134]
JBD Offline
Member

Registered: 07/12/01
Posts: 599
Loc: WI, USA
 Originally Posted By: sparky 134
I received a phone call today from an HVAC contractor who was in the process of changing out the compressor in a RTU which was fed with a grounded B phase system. He wanted to know if he could install a 3phase monitor that would prevent his compressor from running on single phase if the unit lost a phase.


He doesn't need a different motor (which does not exist), he needs a Phase Loss Relay added to his starter control circuit instead.

Top



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