UK Voltage

My location is California.

I've been tasked to specify a control transformer mounted in an enclosure (along with a motor starter) bound for England. My instructions are for (1) 150VA, 416V primary x 220V secondary. Same for (1) 250VA.

I'd like to use Acme but this is an unusual application for me. Two questions:

1. Do the primary and secondary voltages make sense?
2. Aside from Acme, is there a suggested alternative manufacturer that may stock an appropriate transformer here in the U.S.?

1. Yes, those are common voltages in the UK.
2. There should be no problem in finding numerous manufacturers. Google is your friend.

http://www.google.com/#hl=en&tbo=d&sclient=psy-ab&q=1-phase+150+VA+transformer%2C+416+volt+primary+to+220+volt+secondary%2C+in+U.S.&oq=1-phase+150+VA+transformer%2C+416+volt+primary+to+220+volt+secondary%2C+in+U.S.&gs_l=serp.12...100391.102500.0.105454.7.7.0.0.0.5.609.3437.3-1j2j4.7.0.les%3B..0.0...1c.1.2.serp.bK2dLHiFglk&pbx=1&bav=on.2,or.r_gc.r_pw.r_qf.&fp=72bf9325becb8e42&biw=1024&bih=615


Temco Industrial Power Supply has the model TT4470 150 VA (0.15 KVA) for $174 US,and the TT4472 250 VA for $242.
http://www.temcoindustrialpower.com/products/Transformers_-_General/TT4470.html

The voltage ranges for most countries outside of the America's are

3 phase 380 to 415 Volts
single phase 220 to 240 volts

The mid point being 400 volt and 230 volt is quietly becoming the standard +/- a percentage

Your problem with sourcing this in the US is your frequency being 60 Hz and England's being 50 Hz means the US transformer for the VA rating is lacking enough iron in the transformer core and requires down rated

I reckon there are 50-Hz-rated transformers available in the same US brands, such as this TEMCO TT4485. This is a small 1-phase control transformer, so I doubt it will be hard to find. For this size, there is not much difference between 50 and 60 Hz transformers.

http://www.temcoindustrialpower.com/products/Transformers_-_General/TT4485.html

Just a side note
the frequencey has nothing to do with the transformer output or VA rating.
the transformer has a "Turns Ratio"
the Turns Ratio gives you the output so if it is 20:1
then 400v Prim = 400/20 = 20V output
the frequencey is what ever the frequencey is - eg. 100hz Prim 100hz Sec.
the VA is the rated output current times the output voltage
eg 2 amps x 20 = 40VA
Most transformer iron core efficiencey is greatet than 98%

the only way to have multiple input / output voltages is with additional tappings.
FYI
3 Phase transformers still use the transformation ratios
Prim. coil to Sec. coil

iant said:

Just a side note
the frequencey has nothing to do with the transformer output or VA rating.

Click to expand...

Incorrect. Consider the case for a very very low frequency - e.g. DC

L D[AR2 said:

Incorrect. Consider the case for a very very low frequency - e.g. DC

Click to expand...

ok but that has nothing to do with the OP post does it?
the voltages you are reffering to are for electronics - if that was the question I would have answered it.
as far as DC is concerned they do use DC on HV isolation transfomers to turn off supply

I guess to clarify, an example of what I'm looking for could compare with US voltages

High Line Voltage VAC/3φ = 440, 460, 480 (nominal numbers for same)
Low Line Voltage VAC/3φ = 220, 230, 240 (nominal numbers for same Delta transformer) or 208 (Wye transformer)

Control Line Voltage VAC/1φ = 110, 115, 120 (nominal)

When researching a control transformer for my application, how do UK voltages (potentials) compare when I am given the ranges as 416V and 220V?

Agree with Iant that the frequency will not make a difference as this is AC and the winding ratio is what I'd be most interested in determining.

Yes, I have 'Google' for transformers before my original post. It's Sunday here, or I'd call my manufacturer's rep and have him research this for me. I'm on a clock.

Thanks all for the input so far.

...rab

My instructions are for (1) 150VA, 416V primary x 220V secondary. Same for (1) 250VA.

Click to expand...

I guess to clarify, an example of what I'm looking for could compare with US voltages.

Click to expand...

Follow your instructions. If you need the equivalent US voltages, 415 in UK = 480 Volts in US, 220 V as required by your customer = 240 volts in the US on the secondary side. The UK does not have the split-phase neutral that we use in the US, so there is no equivalent 120 volt level. They use 220 or 230 for all lower-voltage purposes (instead of our 240 and 120 volt levels).

You should double-check that 220 volt level. As in the US, there is a lot of confusion about whether the specification is a SUPPLY VOLTAGE LEVEL, or is the MINIMUM EQUIPMENT OPERATING LEVEL. The two parameters are different and usually the minimum operating level is about 10% below the nominal SUPPLY VOLTAGE LEVEL. For example, in the US, many electrical device have a rating of 210, 215, or 220 Volts AC, even though the normal utility supply voltage is ideally 240 Volts AC. You have to know which it is, the equipment minimum rating, or the utility supply level. For a transformer, you should use the utility supply voltage level.

Lancie1 said:

Follow your instructions. If you need the equivalent US voltages, 415 in UK = 480 Volts in US, 220 V in UK as required by your customer = 240 volts in the US on the secondary side. The UK does not have the split-phase neutral that we use in the US, so there is no equivalent 120 volt level. They use 220 or 230 for all lower-voltage purposes (instead of our 240 and 120 volt levels).

Click to expand...

UK is 240VAC, mainland Europe is mainly 220VAC

downgrading 60 to 50 Hz would require to downgrade to nominal voltage for the same percentage. running it on nominal voltage on 50 Hz would cause higher current and cause premature burning of winding. however for small power ratings i guess that could be ignored.

PeterW said:

UK is 240VAC, mainland Europe is mainly 220VAC

Click to expand...

wouldn't be mainland Europe 230VAC?

balash said:

wouldn't be mainland Europe 230VAC?

Click to expand...

This may help -
European Voltage Harmonisation

The United Kingdom for many years had a standardised supply voltage of 240V ±6% (415V for three-phase) whereas continental Europe had a nominal supply level of 220V (380V). From 1 January 1995 the nominal voltage across Europe has been 'harmonised' at 230V/400V.


This is not a real change, since the former 240V countries, including the UK, have in the first stage of voltage harmonisation a tolerance of 230V -6% to +10% (i.e. 216.2 - 253V) as compared with the 'old' limits of 240V ±6% (i.e. 225.6 - 254.5V). However, the former 220V countries (most of Continental Europe) have limits of 230V -10% to +6% (207 - 243.8V).

Effects on Equipment
There is a problem with equipment of North American origin. Many US and Canadian manufacturers continue to design their 'export models' for 220V but also fail to take adequate account of the supply frequency being 50 Hz as opposed to their 60 Hz. This is particularly seen in the design of power-supply transformers incorporated in such products.


The effects vary according to the type of equipment. Over-heating can occur as incorporated voltage regulators have to work harder. Supply transformers which are designed with minimally sized iron cores can easily go into saturation, especially toroidal designs.

http://www.claudelyons.co.uk/energy_saving.htm

Many US and Canadian manufacturers continue to design their 'export models' for 220V but also fail to take adequate account of the supply frequency being 50 Hz as opposed to their 60 Hz.

Click to expand...

Because the customer asked for 220, the question "why 220" needs to be asked of the customer before making a change. Maybe the customer doesn't know what voltage he needs and is just copying old specifications, often the case.

I tend to go for a universal input transformers. It has saved me a lot of headaches when customers give me specs and then when the machine arrives on site the voltage is higher or lower than specified. It also means I can test here with a UK supply and then set inputs for the final destination.

http://uk.farnell.com/block/uste250-2x115/transformer-isolating-250va/dp/1177120

http://www.alliedelec.com/search/productdetail.aspx?SKU=R1070074

They are 50/60Hz and any input voltage to give me 230 on the output.

Don't know why your customer would give you such weird voltages as 416 and 220. As given above the standard in most of Europe now is 400V phase to phase and 230V phase to Neutral (400 divided by square root of 3). Sometimes people specify 220V but they actually mean it is centre tapped 220V giving 110V to earth from each side. They think that 110V is safer than 230V, marginally it may be, but the safest way is to stop people coming in to contact with Voltages in the first place.