EBME Forums Forums Maintenance Technical Assistance 402A Electrosurgical Analyzer

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