Products > Test Equipment
Test Equipment Anonymous (TEA) group therapy thread
Specmaster:
--- Quote from: KrudyZ on May 20, 2018, 10:17:24 pm ---
--- Quote from: Specmaster on May 20, 2018, 10:08:59 pm ---I've seen many various thoughts about whether the earth on the secondary side of the 240v isolating transformer should connected to the incoming earth or left to float. Is there a real answer to this or not?
--- End quote ---
This should probably be in its own thread, but the purpose of an isolation transformer is to remove the earth reference for the line and the neutral. It is not there to remove the earth connection from a chassis.
There are exceptions to this, but you want to be careful, especially when hooking up test equipment which will likely be earthed itself.
--- End quote ---
When hooking up test gear which as you rightly say, is likely to be earthed, it shouldn't be a problem surely as any voltages within the DUT are derived from a source which has no earth reference any way?
bd139:
It all depends if you become a lumped element in the circuit or not :-DD
Specmaster:
--- Quote from: bd139 on May 20, 2018, 10:27:43 pm ---Yep. There be dragons all around.
I tend not to use my isolation transformer at all preferring the one built into the DUT. If the primary side of a switcher has gone bang, all diagnostics are done 100% off line. If mains is poorly wired or exposed this is fixed before proceeding. In the case of the deadly Fluke 8000A the entire device is run off D.C. after the transformer taps on a bench supply.
My isolation transformer is a monster as well so I can’t be fucked with getting it out. It’s an 3KVA variac with two back to back 50v transformers. Weighs about 30kg and lives in the cupboard under the stairs. Cost me £0 if I took it away which I did and it hasn’t moved for about 8 years. Plus it’s probably more dangerous than not using one.
--- End quote ---
Thats a big bugger you've there, mines only a 500VA and is a straight forward 1:1 transformer which is heaps for me, if I need to vary the out I plug a small variac into it.
bd139:
I can run my Henry off mine :D
I’m going to lose it when I can be bothered to dig it out. Give someone a hernia :)
Specmaster:
I bet its got quite an inrush when you first switch it on too.
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version