Distribution for 415V/50Hz supply

[EETD]

Hello all,

I am working on a project in South America in which the supply will be 415V/3Ph/50Hz, 4-wire. The requirement has been made that lighting and control system loads (i.e. motor starters, I/O, etc.) should be at 110V.

In the states I am used to using a 3Phase 480-208Y/120 transformer for lighting, and a 1Phase 480-240/120 transformer for control system loads.

Is there a standard delta-wye transformer for lighting use in this application?

Is there a standard 1Phase transformer for use in this application that would achieve 220L-L and 110L-N?

The closest I have found so far is a three phase transformer with a 415V delta primary to 220/110V delta secondary.
However, this transformer would only have 110VAC between two phases because it has a center tap between two legs. Not my first choice due the possibility of unbalanced loading.

Thanks in advance for any suggestions.

 

[busbar]

Long shot possibility…
Use 460V-primary at 415V — 220Y/127V secondary operates at 208.4Y/120.3V at 5% FCAN

See

http://www.jeffersonelectric.com/pdf/3-PhaseVent.pdf

page 5 for 15-150kVA drytypes

Latin American Voltages 460 V — 220Y/127 V
150°C Temperature Rise • 2 – 2.5% FCAN 4 – 2.5% FCBN Taps
[NOTE: 50HZ OPERABILITY UNKNOWN]

 

[rbulsara]

Transfomers cab be built to any voltages you specify....contact a few mfrs...

Yours is a special requirement..and hence need to specify custom xfmrs.

The norm with 415V system is so use 415Y/240V systems without the use of transformers and 240V as lighting and controls.

On the other hand..motor controllers and MCC's can be specified with 415V:110V control transformers. Why would you want lightig at 110V, I would keep it at 240V. Even in the USA, lighting (except for residential and dwelling units) is 277V.

If you keep your receptacles at 110V, you will not find many appliances that work on 110V and 50hz. They normally are designed for 110V, 60hz or 220-240V, 50hz.

 

[RRaghunath]

I agree with rbulsara.

Lighting is kept at 240V. The control and indication lamp power supplies alone are at 110V level in case of 415V motor control centres in industries for safety reasons.
The 110V control power is derived from 415/110V single phase control transformer located in one of the MCC modules.

 

[Rodmcm]

Usually all power and lighting distribution is done from phase to neutral ie 415/R3 - 240 V Cxontrol supplies for 110VAC and the like are ofter sourced from 240/110V instrument transformers (dry 100VA type rating)

 

[babylon]

110V supplies are used for control purposes in europe. you need a single phase 240V supply feeding a safety isolating transformer, with 55V live / 55V neutral, which is classed as safety ELV, which provides a reduced shock potential. This system is also used for construction works tools and ligting supplies.
I guess that you guys in the states are unfamilliar with european standards. This is a very standard piece of equipment here

 

[ScottyUK]

Hi babylon,

Per the IEE wiring regulations The term SELV is reserved for Separated Extra-Low Voltage, and is defined as "An extra-low voltage system which is electrically separated from earth and other systems in such a way that a single earth fault cannot give rise to the risk of electric shock." and further defined as "Normally not exceeding 50V AC or 120V DC, whether between conductors or to Earth."

The 110V centre-tapped-earth system you refer to is not an SELV system. Refer to section 411-02 of BS7671 for more details.





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