Brothers (and Sisters?),

Can anybody help out with a manual for the DNI Nevada 402A Electrosurgical Analyzer?

Also, would anyone like to comment on the need for adding a capacitor between sockets 3 and 4 of the same unit in order to obtain a reading (that’s between the neutral side of the meter and earth)? Surely, if needed, such a capacitor should be built in?

For the first plea, I'll take that as a "no" then! The jury's still out on the second part as far as I'm concerned. Any comments from anyone?

Hi Geoff,

Where do you get the idea of the capacitor from if you don't have a manual?

YES, there are a few of the "fairer" sex out here.

Only have 454a, sorry.

Tracy

Slightly off topic, but yes and what excellent Biomeds they are too. Tracy Good on yer

On some types of ESU (guess which type - there are 'Floating' and 'Earth-Referenced' @ HF) you sometimes need to "earth-reference" the 'neutral' side of the meter to 'tie' the ESU dispersive to the ESU tester earth, at HF, (the ESU tester earth should be,connected to the ESU earth directly) to compensate for the imbalances in the leakage paths that 'present themselves', at HF, to the active and dispersive circuits within the test instrument and the effects this has on dispersive voltages due to leakage wrt Earth - those significant leakages that occur at higher power settings.

The capacitor effectively 'ties' the dispersive, at HF, to the earth of the tester and ESU. Any active leakage currents are also referenced to this earth (and that of the ESU which should be connected to the earth terminal supplied on the tester). For testing purposes you need to earth-reference the ESU dispersive at higher power settings because of the relatively significant imbalances in leakage paths, within the ESU leads, and the ESU tester, that cause ESU alarms when active current is not equal to dispersive current and when the leakages cause the dispersive to 'float' wrt Earth. The relatively low leakages at lower power settings do not cause problems.

The earth-referencing capacitor prevents these alarms from occurring at higher power settings and under conditions where there can be significant imbalance in active and dispersive circuits WRT earth and significant dispersive voltages as a result. This prevents problems on ESU's that monitor imbalances between active outputs and dispersive return currents within the test circuitry, that is earth referenced internally, and the dispersive voltage that would otherwise 'float' WRT Earth. otherwise imbalances in leakage between the active circuit and dispersive circuit cause difficulties at high power settings in particular.

Surely the use of this method is common knowledge to anyone purporting to be a 'biomed' that has used any form of ESU tester.

Is this a joke or are you being serious?

Strike the previous post - no Adrian I was not joking I am just surprised that no other 'biomeds' have ventured forward with anything. I take it back.

Thank you, Richard, for your illuminating dissertation and kind comments. Geoff

Richard,

Could you please play nicely. All somebody asked for was a manual, not a lecture.

Colin

Sorry Geoff I wasn't trying to lecture and my previous comments were made more in surprise that you didn't get any other biomeds' feedback - not to you directly but I can see how it reads so I apologise to you. I think the capacitor will sometimes be required, sometimes not - depending upon the type of ESU being tested, built-in alarm features and the leakage associated with leads and accessories.

Yes Col you are correct I am at fault and my comments were offhand. I am sorry.

Richard,

I am all for the exchange of information. It would be a shame if people stopped using this forum to ask for assistance because when you add this;

Quote
Surely the use of this method is common knowledge to anyone purporting to be a 'biomed' that has used any form of ESU tester.
Unquote.

to a post, I see it as sniping. Everything before it is valid and useful. Adding comments at the end I feel devalue the content.

Not only my opinion. My colleagues alerted me to the fact that 'Richard is off again'

regards

Colin

Maybe it is time for me to 'sling my hook' as they say.

Tara.

Come back Richard! What would my miserable life be worth without your daily wind-up? Keep up the good work, Mate, the "Brothers" need you!

I agree with Col. It would be a great shame if people stopped using the site to seek advice because they got shot down in flames for their apparent lack of knowledge.

It's not the people who know that they don't know who are dangerous. It's the ones who think that they do know.

Keep the questions coming and hopefully everyone can learn from the answers and the discussion that follows.

Spot on Roy Well said Mate. T.

Apparently my posting has been interpreted as a personal insult by a member of the site. I would like to point out that it is split into three paragraphs - which since they deal with different issues could have been put in three seperate postings - but I chose to include them in one.

P1) Col made a good point and I think sharing information and being able to ask questions are an important part of the EBME site. This should be encouraged and the people who have the courage to ask shouldn't be ridiculed.

P2) This is aimed at the people who ask the questions, not at anyone who has taken the time and trouble to reply ! Asking questions when your not sure is far safer than blundering on in ignorance. Some people see admitting you don't know as a weaknes - but it can take courage to ask what you know is probably a basic question. This forum should provide a simple route to a wide range of information - and opinion.

P3) Sometimes people ask questions you wish you had asked - because you realise you don't know the answer either - and the replies can be enlightening even if you believed you did understand the issue.

Keep the questions coming - and the discussion that usually follows. We can all learn from one another and hopefully that knowledge will make our hospitals a safer place and keep our equipment working for longer. The medical equipment that is

Spot on again Roy

I takes a good competent engineer to acknowledge his/her limitatations and ask for assistance when needed. We are all on the path of life long learning and will come across things that we are not sure about on a regular basis, this is all part of the learning process. Only a foolish or dangerous engineer will just plod along in silence and hope for the best.

Keep up the good work Roy