Busbar Ductor Testing

[bcm_spark]

Now I haven't done a lot of this and it's been 9 years since I last did it.

We have a big bus bar section to test with numerous joints. Now the fella I am working with wants to link out let's say L1 and L2 and then put the test leads across L1 and L2 at the other end and take a reading!! I feel like knocking some sense into him but can't.

Now maybe it is me who is being daft but I want to put my current leads on the L1 busbar let's say, one at each end. Then the voltage leads across each joint to measure the resistance of each joint. Then repeat for each busbar.

Someone help me educate this guy or maybe it is me who needs sense knocking into??

 

[James]

link L1 and L2?
I presume this is dead testing otherwise I would stand well back whilst he sets this up!!

 

[Bobster]

Personally, I test each joint on it's own.

However, there's no hard an fast rules on it. You could proceed with how your colleague suggests, but you're going to accumulate any poor readings, an will be hard to tell if joints are suitable or not. So you're going to end up testing separately anyway.

Plus, future maintenance will not show which joint is failing or getting worse with age easily.

 

[bcm_spark]

Yes dead testing.

Apparently it is how he did it 9 years ago here and lots of calculations.

I have retired to the office and left him to it.

The whole point is to check soundness of joints, ie tight and low resistance. Not measure resistance between phases. Which have been linked out by him to perform test. Bloody bizarre.

I really want to give his head a shake!!

 

[snowhead]

How would you / he know if the value was correct?
It's a pointless and lazy way of testing.

If you knew the original built value of total resistance per bar, it might be worth testing end to end.
But it's quite likely at least 1 joint will need tightening.

As Rob, I'd test across each joint.
Any with higher resitance tighten up and retest.
If that still doesn't match a similar joint, it'll have to be stripped and cleaned.

 

[Bobster]

The thing is, the resistance values you are measuring are so small, that trying to speed the testing up by covering a larger area all in one go, makes it counter intuitive.

 

[bcm_spark]

He just creates work. I didn't make it clear properly, he isn't linking the bars to reduce the amount of testing as he also tests each bar separately then does some degree level mathematics to get the final result. Personally I don't think he knows what he is doing and is making it up as he goes along plus he seems to think it makes him look clever.

I've personally inspected, cleaned up and torqued all joints already and know everything is sound but even so still needs a test.

I'm not getting involved any further but it is quite humourous watching though

 

[Charlie_]

Please put up his fancy mathematics for us all to have a look at when he’s done

 

[Bobster]

Doubtful it's degree level math, it's basic Ohms law. That's top and bottom of it.

I would also be interested in seeing some of the math, off the top of my head I can't think of what he would be doing.

 

[bcm_spark]

I was being sarcastic Rob sorry. No need for any math though as you do the test and write down the result. No need to make things difficult.

It is something like

(L2+L3)-(L1+L2)=L1
(L1+L3)-(L2+L3)=L2

(L2+L3) etc etc being the result of linking the 2 busbars and testing between.

These two results added together equal L3

Then
L1+L2=R2
L1+L2+L3=R1+R2

Total bamboozled me.

I wish I was kidding but I'm not. I'm just sat here laughing to myself. The guy should know better as he has had many years in the game, a lot more than me.

He has said we will do it his way first then my way second. At least I know itll be done correctly and it's good to take the ---- out of him too.

 

[Moley]

Our company policy is to test each joint. His method won't show up any individual high joints.

 

[bcm_spark]

Our company policy is to test each joint. His method won't show up any individual high joints.

Exactly

He's still at it now. Started at 10 ish

 

[bomjac]

Modern Ductor tester, takes 10s for each test. All stored internally and can be downloaded to PC. Compared to the amount of faffing about making shorts, calculation and repositioning the shorts, I know what I would be doing. The only issue I ever found with busbars was over-torque, construction guys had been at it with their big-boy spanners and tightened the sections too much causing high resistance. Had to go back, loosen them all and have them redone to the right torque.

We have Fluke Battery testers, that you can test the cell resistance and internal impedance on a each cell in a 120 cell battery in literally 5 minutes. Hook it up to a PC an you can instatly identify any weak cells.

 

[bcm_spark]

The ductor tester we have doesn't store the readings that is the next model up from ours. Not too much hassle to be honest.

I use a celltron battery analyser, sounds similar to your fluke. Tests each cell, readings in mhos and tells you whether it is good or not and you can identify deterioration and change out before they fail.

 

[Toneyz]

How long is the bus-bars?