Parallel Secondary

[Joseph]

Jake or Electrical Guys,

What do they mean when there is a transformer box (may be junction box) and it is stamped "Parallel Secondary"? Just curious...

Joseph

[Oscar_Lives]

DON'T wire it in series!

Tekkie will have more details in a bit.

[Jake]

That can depend a lot on where it is and what it's used for...

Since it is marked, I'd assume it is either on a piece of equipment or in a distribution system.

Generally... if they're marked... it means the system is utilizing a 'auto transformer' specifically wired for good voltage regulation.

This happens a lot in higher end 'boost' transformers. A lot of audio-type systems use a parallel secondary.

Series (primary)/Parallel (secondary) transformers are common in industrial settings. A 480 x 240 V transformer (with 120V taps) is wired this way... although seldom marked. I've used some bigger ones to go

460-600 and 460-380.

What kind of equipment is connected to it?

Jake

[Joseph]

it

Its the incoming service on a 3 story hotel building. There are couple of clearly identifiable transformers and a couple of other boxes that are the feed to the entire building. I think there were two or three clearly stamped Parallel Secondary.

So a Secondary parallel means multi-taps on a transformer. e.g. 1-460v,

3ph to two parallel taps of 230v, 3ph? Or is this a way of taking 460v, 1ph and making it 230v, 3ph? I was imagining it to be a double wrapped transformer? I haven't researched any of this just yet; I was just curious and lazy, thanks for the input...

Joseph

[Dido]

No it means that transformer have dual winnings on secondary and are parallel to increase current multi-taps can not be parallel on any transformer on ones I came across from 5vac to 5kvac DIDO

e.g. 1-460v, 3ph to

[Jake]

Ahhh... a hotel. That may explain the system and why they are marked this way. Many local code variations require high-density multiple occupancy dwellings to have backup power in some flavor.

Sometimes... this is accomplished by numerous means. For example, the building can have two separate primary feeds.. from different locations... servicing the buildings. Two different sets of transformers may supply secondary power (in parallel). I've mostly seen this done at high rise buildings and large prisons.

Building owners (with generation capability) have also embraced DG (Distributed Generation) as a way to help with their energy costs. Their own generators can be fired off and help meet network demands upstream at a premium cost to the utility. DG may require parallel secondary circuits in order to properly 'upload' energy to the system in need.

The key is that this equipment is marked as such. A regular distribution transformer... which may very well have its own secondaries in parallel... is a common occurrence and no-one would bother. Marking one like this is warning to the service personnel that other sources of energy probably exist outside the transformer's own primary circuit.

Jake

>

[Tekkie®]

Oscar_Lives posted for all of us... I don't top post - see either inline or at bottom.

Thank you. It is a perfect opportunity to discuss copper tubing fuses. Oh wait a minute I must digress... First we must touch upon Stumpy. The parallel parts of him are his mouth and asshole. Now the problem is what is coming out of these? In the final analysis what one must conclude that stupidity is secondary to idiocy.

Joseph, I hope I have helped to enlighten you in some small and humble way. If I can be of further service to you please don't hesitate to ask.

I must ask though did this hotel have rooms rented by the hour? Was it's name the "Come & Go"? Maybe the "Hot Sheets"? I did not stay at Holiday Inn Express lat night.

[Joseph]

to

thx, Joseph

[Joseph]

Good one... LOL

I'll assume rhetorical questions... thx :)