3 Phase Transformer Question

[Jody Boehs]

I have a new packaging machine coming to our plant. The spec sheet shows it is 400V 3ph. (odd voltage in my opinion) or 230V 3ph. if we get the standard version (still not sure what version they ordered). Our plant runs on 480V 3ph. wye.
Obviously I can transform from 480 to 230 but the transformer I was looking at is a Delta wired transformer. I understand the primary side is usually wired in Delta. The secondary side is also Delta wired. If I put 480V Wye into the primary side, Will this create a "high leg" on the secondary side since it is wired in Delta?
I've energized numerous transformers (that are wired in Delta on the primary side) with 480V Wye, but have never worked with a Delta wired secondary side.

The other option I have is if they got the 400V option, then I'll have to find a special order transformer to drop 480V to 400V.

 

[LarryFine]

If I put 480V Wye into the primary side, Will this create a "high leg" on the secondary side since it is wired in Delta?

No, a high-leg delta happens because of the secondary conductor that is chosen to be grounded; in this case, the center tap of one secondary winding. It has nothing to do with the primary configuration.

I've energized numerous transformers (that are wired in Delta on the primary side) with 480V Wye, but have never worked with a Delta wired secondary side.

You should choose the secondary configuration to match your needs. A wye secondary is required in most cases where the load needs a neutral, and makes grounding simpler than using ground-detection.

The other option I have is if they got the 400V option, then I'll have to find a special order transformer to drop 480V to 400V.

That's probably your best bet. In any case, I recommend a delta primary and a wye secondary.

 

[Julius Right]

If V2=2xπXf2xϕ and V1=2xπXf1xϕ where V it is EMF in the induction motor stator f it is the supply system frequency and ϕ it is total magnetic flux then V1/V2=F1/F2 480/400=60/50 .That means the packaging machine is made for 400 V 50 Hz and it will fit to 480V and 60 Hz

 

[xformer]

If V2=2xπXf2xϕ and V1=2xπXf1xϕ where V it is EMF in the induction motor stator f it is the supply system frequency and ϕ it is total magnetic flux then V1/V2=F1/F2 480/400=60/50 .That means the packaging machine is made for 400 V 50 Hz and it will fit to 480V and 60 Hz

might run a lil faster.

 

[tortuga]

What If its a 60 HZ? OP did not specify its 50hz

 

[tortuga]

I'd look into a transformer or even better an autrotransformer and create a 416Y240 panel.
416Y240 is the most common voltage that's not in the NEC under article 220.5 standard voltages.

 

[petersonra]

I have a new packaging machine coming to our plant. The spec sheet shows it is 400V 3ph. (odd voltage in my opinion) or 230V 3ph. if we get the standard version (still not sure what version they ordered). Our plant runs on 480V 3ph. wye.
Obviously I can transform from 480 to 230 but the transformer I was looking at is a Delta wired transformer. I understand the primary side is usually wired in Delta. The secondary side is also Delta wired. If I put 480V Wye into the primary side, Will this create a "high leg" on the secondary side since it is wired in Delta?
I've energized numerous transformers (that are wired in Delta on the primary side) with 480V Wye, but have never worked with a Delta wired secondary side.

The other option I have is if they got the 400V option, then I'll have to find a special order transformer to drop 480V to 400V.

I guess your first chore is to find out what they actually bought. Most cases it is a good idea with 3 phase (for various reasons) to choose a transformer with a delta primary and a wye secondary. I would be looking at what the power frequency is supposed to be as well. It may not care if it is 50 or 60 Hz.

400 V sounds like the "standard" European 3 phase voltage of 400 V/230 V at 50 Hz. The 230 V version might be a single phase version at 50 Hz. hard to tell with European machines. If it is 230 V 3 phase, that is not a standard European voltage, so maybe that version is 230 V, 3 phase, 60 hz.

 

[winnie]

No, a high-leg delta happens because of the secondary conductor that is chosen to be grounded; in this case, the center tap of one secondary winding. It has nothing to do with the primary configuration.

To amplify this a bit:

The primary source configuration doesn't matter, no does the primary winding configuration. What matters is the secondary.

If you have a delta secondary, then you have the choice of a 'high leg' delta, a corner grounded delta, or an ungrounded system. The only thing you can't get with a delta secondary (without additional transformer hardware) is a standard 'wye' output.

Regarding this unit coming from Europe...I'd double check its frequency requirements. It may very well require 50Hz...or it may simply operate faster at 60Hz, or it may use a VFD for any motors and need a wye source.

-Jon

 

[Rick 0920]

I once had to wire up a flour sacking machine in Kansas. The nameplate stated 460v 50Hz. I called the manufacturer in Italy to confirm and was told the machine could fail at 480v. I had to use a step down transformer from 480v to 460v and they said Hz would not be an issue in this case. Moral of the story, make the phone call!