ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
ShoutChat Box
Recent Posts
Happy Thanksgiving
by gfretwell - 11/26/20 08:52 PM
Insulated Tools: A Waste of Money?
by HotLine1 - 11/26/20 12:28 PM
Ground fault remover :-)
by NORCAL - 11/26/20 08:13 AM
Work Gloves?
by sabrown - 11/25/20 01:54 PM
What does your work place look like?
by Lostazhell - 11/25/20 02:56 AM
New in the Gallery:
Facebook follies, bad wiring
FPE in Germany pt.2
Who's Online Now
0 registered members (), 12 guests, and 15 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
10 kva transformer #39552 06/25/04 06:15 PM
Joined: Jan 2004
Posts: 171
M
Merlin Offline OP
Member
I need a little assistance guys. I am setting up our new pumping station at work.
I have to install a 10 kva transformer. I personally have never installed one of this size before. I am used to the little 0.75 kva's for control circuits.

My question is: this thing has 8 wires (as I remember) labeled H1, H2, H3, H4, X1, X2, X3, and X4. I know the H's are the primary and X's secondary. But how are they wired? I have my idea but am not positive. Thanks for any help.

Work Gear for Electricians and the Trades
Re: 10 kva transformer #39553 06/25/04 06:41 PM
Joined: Sep 2001
Posts: 806
N
NJwirenut Offline
Member
How to connect the wires depends on the available input voltage, and the desired output voltage. The 4 wires on primary and secondary are actually 2 separate windings on each side of the transformer, which are connected in series or parallel as required by the specific installation.

Re: 10 kva transformer #39554 06/25/04 06:52 PM
Joined: Jan 2004
Posts: 171
M
Merlin Offline OP
Member
Sorry, I forgot to mention that the primary is 480 volt 3 phase and the secondary is 120/240 single phase.

Re: 10 kva transformer #39555 06/25/04 07:32 PM
Joined: Sep 2001
Posts: 806
N
NJwirenut Offline
Member
ASSuming that the transformer uses standard terminal designations, you would tie H2 and H3 together, and connect the incoming 480V lines to H1 and H4.

On the secondary side, connect X2 and X3 together, and use them as your neutral. you should get 120V from X1 or X4 to the neutral, or 240V across X1 and X4. As the secondary of the transformer is a separately derived source, the neutral needs to be grounded close to the transformer.

Again, these instructions ASSume standard labeling is used. Check the nameplate or manufacturer's instructions to be sure of your connections.

Re: 10 kva transformer #39556 06/25/04 09:09 PM
Joined: Jan 2004
Posts: 171
M
Merlin Offline OP
Member
NJwirenut

Thank you for the info. I thought that was how it was done but was unsure. I haven't run across the labeling or instructions yet. This was ordered by my engineer about 7 or 8 months ago and I just started this project. Thanks a million for your help!!!

Re: 10 kva transformer #39557 06/25/04 09:57 PM
Joined: Apr 2002
Posts: 2,527
B
Bjarney Offline
Moderator
A couple of notes —
Do not overlook Article 450 primary and secondary overcurrent protection and Article 250 {equipment and} secondary grounding for separately derived systems.

Plain-vanilla 150°C-rise drytypes run blistering hot approaching rated load. Manufacturer’s clearance requirements and minimum field-installed conductor-insulation temperature ratings are also very important.


Featured:

2020 National Electrical Code
2020 National Electrical
Code (NEC)

* * * * * * *

2020 Master Electrician Exam Preparation Combos
2020 NEC Electrician
Exam Prep Combos:
Master / Journeyman

 

Member Spotlight
Vlado
Vlado
Croatia
Posts: 28
Joined: February 2011
Show All Member Profiles 
Top Posters(30 Days)
Trumpy 9
Popular Topics(Views)
271,985 Are you busy
205,871 Re: Forum
193,933 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.7.3