240V 1ph 2 hots wires VS 240V 1 hot wire-N 1

[jor1492]

Its known that 240V can be obtain typically (US) as 1ph, 2 hot wires (120v each) commonly used for domestic A/C units, for example. I have now seen a few equipments from different countries where 240V is obtained by having a 480 primary / secondary 415-240V 3phase transformer and connecting 1 hot wire-neutral (240V). Is there any difference between this two methods to obtain 240V for a given equipment? Would the equipment get damaged if its connected one way or the other if its commonly connected in one given way?

 

[benta]

If it's standard 230 V single-phase equipment as used in for example the EU, it doesn't matter. It's laid out so you can reverse live/neutral with no problems.
This to ensure that noone/nothing gets damaged if you reverse the plug or the electrician did a bad job.

 

[jor1492]

Hi benta! Thanks for your reply.

I think I did'nt explain myself correctly. To sum up, my question is. Is there any issue to connect an equipoment wich requieres 240 V, to a 240V 2 hot wires outlet (two 120V hot lines) system or a 240V 1 hot wire outlet (240V line to Neutral line) system.

 

[itsmoked]

Typically there is no issue but there certainly can be.. For starters in the USA system no insulation would be stressed to more than 120V above earth. Applying 240V-N to that system will instead stress things to 240V to ground.

If the device/machine is fed a neutral than it should be assumed there are devices/circuits within that expect to see only 120V. In that case supplying 240V-N will definitely zorch things.

A lot of international machines don't take a neutral and have control transformers that drop the control voltages down to something less like 120V or 24V. The control transformers don't usually care about the style of 240V.

It's worth examining a machine to see what makes sense. No neutral is a good start. If the machine has just a single phase motor and some switches it likely doesn't matter. If it's a computer driven machine check for switching supplies that usually don't care about 240V types.



Keith Cress
kcress -

http://www.flaminsystems.com

 

[benta]

Perhaps I didn't understand the question completely.
From what I read, you have equipment with a 230/240 V input, L + N.
You can supply it from 230/240 V L + N of course (that's what it's built for).
And yes, you can supply it from 120/120 V split phase (=240 V) as well.
No problems.

As Keith notes, the other way round is a different story.

 

[waross]

Rather than a 240V/480V system you are more likely to find a 220V/380V system or a 230V/400V system.
That is the European version of North America's 120V/208V systems.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[cranky108]

North America also has 277/480. However, there is also a 3 phase 240 delta, with a center tap on one of the transformers, to give a pair of 120V, and 240v delta. It's not used much, but it does exist.

 

[jor1492]

Thanks all by your answers guys. very helpful

 

[waross]

"North America also has 277/480." and 347/600 Volts.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[ScottyUK]

C'mon Bill, you're not North America - you're in Canada!

 

[crshears]

We may be North, but we're not American...

CR

"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]

 

[waross]

We could have been Americans.
There is a clause in the Declaration of Independence that has the voting procedure for approving future applications of territories wishing to join the Union.
Canada was pre-approved for admission into the Union, all other territories had to pass a vote.
Check the Declaration of Independence.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[cranky108]

Canada is part of North America, just like Mexico is.

Lets not go down the road of debating locations. Yes I said North America, meaning the US because someone did before me.

I have no idea of what most countries have for standards, other than the US, and what I have seen in my limited travels.

But I have seen light bulbs in three different voltages, and all with the same edison base. Seems like a problem waiting to happen.