Adding a Neutral for 50Hz Equipment

[mikev86]

Hello all! Working on a project in the US where we have an inverter to convert voltages for European equipment. Primary side of the inverter has (3) phase conductors and (1) grounding conductor. Secondary side of the inverter is also (3) phase conductors and (1) grounding conductor. We have a new piece of equipment (600Y/347V) coming that requires a neutral. A few questions below:

1. Does a neutral need to be pulled from the source panelboard to the fusible safety switch and to the inverter?
2. For the neutral between the inverter and the 600Y/347V panel:
   • Can this neutral be pulled in a separate EMT conduit run adjacent to the phase conductors?
   • Or will we need to replace the existing conduit with a larger conduit and run the neutral in the same conduit?

Thanks in advance!
Mike

 

[tortuga]

Hello all! Working on a project in the US where we have an inverter to convert voltages for European equipment. Primary side of the inverter has (3) phase conductors and (1) grounding conductor. Secondary side of the inverter is also (3) phase conductors and (1) grounding conductor.

Grounding conductor and neutral are two different things, you probably mean neutral, check the specs of your inverter to be sure or post a pic of the nameplate.

We have a new piece of equipment (600Y/347V) coming that requires a neutral. A few questions below:

1. Does a neutral need to be pulled from the source panelboard to the fusible safety switch and to the inverter?

Probably not the inverter docs would say either way

1. For the neutral between the inverter and the 600Y/347V panel:
   • Can this neutral be pulled in a separate EMT conduit run adjacent to the phase conductors?

No

1. • Or will we need to replace the existing conduit with a larger conduit and run the neutral in the same conduit?

yes

Thanks in advance!
Mike

 

[mikev86]

Grounding conductor and neutral are two different things, you probably mean neutral, check the specs of your inverter to be sure or post a pic of the nameplate.

Probably not the inverter docs would say either way

No

yes

Thank you so much for the quick reply! I was able to confirm with Visicomm no neutral required on the input side. I can't figure out how to upload photos, but Visicomm Model: 140IND6050 is the model number of the converter. Input 460V/3PH/60Hz Output 230/400V/3PH/50Hz.

I will advise that we need to run a new conduit to replace the existing to add a neutral on the output side.

Thank you!

 

[tortuga]

You originally mentioned 600Y/347 50hz and that inverter output is 230Y/400 50hz.
Note in my recent experience with new IEC / EU equipment with VFD drives its often is now 50-60 hz rated so we just use a 416Y240V transformer rather than a frequency converter..

 

[mikev86]

You originally mentioned 600Y/347 50hz and that inverter output is 230Y/400 50hz.
Note in my recent experience with new IEC / EU equipment with VFD drives its often is now 50-60 hz rated so we just use a 416Y240V transformer rather than a frequency converter..

I will check to see if the equipment will have drives, thank you for flagging! Since we already have a converter, would there be a benefit to a transformer?

We already have the 230Y/400V 50Hz panel in place. We need to bring a neutral to that panel and our end goal is to bring a new feeder out of the existing panel to serve a new panel and new equipment.

 

[winnie]

Can you clarify, where does 600Y/347 50Hz fit in this picture?

Is this correct: You have an existing inverter with 400Y/230V 50Hz output, feeding a panel. The neutral was not brought to this panel. You now need 600Y/347 50Hz _with_ a neutral for the new equipment?

-Jonathan

 

[mikev86]

Can you clarify, where does 600Y/347 50Hz fit in this picture?

Is this correct: You have an existing inverter with 400Y/230V 50Hz output, feeding a panel. The neutral was not brought to this panel. You now need 600Y/347 50Hz _with_ a neutral for the new equipment?

-Jonathan

Hi Jonathan, you are correct. Nameplate on the inverter reads 400Y/230V 50Hz. This feeds a panelboard where the nameplate reads 600Y/347V 50 Hz and we need to bring a neutral to the existing panelboard. It is my understanding that phase to ground is 347V and phase to phase is 600V.

We are then feeding a new panelboard and a new piece of equipment. The only information I was given so far on the new equipment copied below:

• "voltage of 380-400V 50Hz. 3 outer conductors / 1x neutral conductor / 1earth.
• the outer conductors protected with 63A screw fuses.
• the main cable should be a 5-core cable. 5x16mm2. 3P/N/PE"

Thank you,
Mike

 

[winnie]

Ok, so the panelboard labeled 600Y/347V 50Hz is a bit of a red herring, because you will not be using 600V anywhere. It is generally fine to use circuit breakers and panels below their maximum rated voltage, unless there are devices that actually measure voltage or are powered from the supply.

Yes, you are going to need to pull a neutral from the inverter to the new panelboard, presumably via the existing 50Hz panelboard.

If the equipment can actually use 60Hz, then using a transformer rather than an inverter is probably slightly more efficient, but probably not a big difference. But if the equipment can only use 50Hz then you are forced to use the inverter.

-Jonathn

 

[tortuga]

Hi Jonathan, you are correct. Nameplate on the inverter reads 400Y/230V 50Hz.

I'd call that your nominal system voltage, so thats what i would use for calculations (220.5), it might even be considered a separately derived system.

This feeds a panelboard where the nameplate reads 600Y/347V 50 Hz

Jonathan beat me to it, yeah a panelboard namplate is usually just the maximum voltage the panelboard is rated for, just like you often see 240V panelboards on 208 systems, no reason you cant use a 600V panelboard on a 400V system, just make sure the breakers are 50hz or 50/60 hz

We are then feeding a new panelboard and a new piece of equipment. The only information I was given so far on the new equipment copied below:

• "voltage of 380-400V 50Hz. 3 outer conductors / 1x neutral conductor / 1earth.

380Y/220 is the utilization voltage

• the outer conductors protected with 63A screw fuses.
• the main cable should be a 5-core cable. 5x16mm2. 3P/N/PE"

The AWG equivalent to 16 is 6 AWG.

Thank you,
Mike

If you want to follow IEC colors you need special permission in writing per NEC 90.4