Rope Busbar - Design 1

[Ninja_Newyork]

Hi,

I would like to know the design calculation for rope busbar. My desired AC current is 4000A 690V. I am planning to use the rope busbar at the output side since am not able to use the solid busbar as my transformer side is too much assembly variations. So to avoid that am planning to use the rope busbar, but i am worried about their current carrying capability since am the cross section is not uniform through out. For solid busbar we are using DIN 43670 & 671 as a design guideline. But for rope busbar do we have any such standards or calculation to verify my design.

 

[waross]

Do you mean cable?

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[9wearSuave]

waross I think OP is referring to flex busbar

 

[b_gibb]

I assume you mean flex bus?

If so, follow the manufacturer's specifications for ampacity. I've used Nvent Eri Flex Bus before and it's been good. Expensive, but easy to install and a good product.

https://www.nvent.com/en-ar/eriflex/products/nvent-eriflex-flexbus-conductor-0

ben
bengibb.ca
powerdesignerpro.com

 

[che12345]

Ninja_Newyork (Mechanical)(OP)24 Oct 23 13:39
"..#1. I am planning to use the rope busbar at the output side since am not able to use the solid busbar as my transformer side is too much assembly variations".... #2. ... am planning to use the rope busbar, but i am worried about their current carrying capability since am the cross section is not uniform through out. ...#3. For solid busbar we are using DIN 43670 & 671 as a design guideline. But for rope busbar do we have any such standards or calculation to verify my design."
My understanding the terminology "rope busbar" is not used in the EE. It seems " flexible braided busbar" fit your application.
1. You only need a short length of flexible braided busbar (FB BB) say <200mm , with one end bolted on the vibrating transformer terminal palm and the other end bolted onto the fixed busbar. You do NOT have to use (FB BB) to replace the fixed BB. These (FB BB) can be of either material Cu/Al, insulated/uninsulated , length, voltage and current ratings.
2. All OEM of (FB BB) do give an indication of current rating in AC/DC. You can select a lower current/area ( A/mm[sup%]2[/sup] ) from their standard product range.
3. Use the (FB BB) OEM recommendation. Increase the Area by say say 10-15% would be adequate.
3.1. Note: 1. DIN 43670 & 671 rating is based on indoor 35 deg C ambient and conductor 65 deg C ....and other conditions.
2. For your case the bar spacing may be much bigger and conductor temperature could be higher, depending on the material and contact surface treatment. See IEC for more detail.
Che Kuan Yau (Singapore)

 

[waross]

If you use parallel conductors, they will tend to pull together under as the current increases.
Even relatively short runs will be affected.
Consider installing spacers to prevent relative movement between parallel runs.
If you are able to move parallel runs together and apart by hand the magnetic forces will move the cables.
I have seen this at under 1000 Amps on 480 Volts.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!