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PostPosted: Wed Dec 10, 2008 9:23 am 
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Joined: Tue Sep 16, 2008 6:51 pm
Posts: 1423
Location: SW Indiana
When talking about analog vs digital meters no matter what they are reading. An analog is always easier to read at least to get a quick overview. You can glance at an analog meter from across a room and see the needle is in the normal position.

Digital meter require a brain process. You have to read a number and mentally conpare that to a normal reading. It is easy to misread an abnormal number as a normal one.

Now granted, digital is more precise. But most times a ball park number is fine. And open vs a shorted conductor is perfect example.


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PostPosted: Wed Dec 10, 2008 6:46 pm 
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Joined: Mon Jul 09, 2007 5:11 pm
Posts: 899
Location: NEPA
Plus there are times when a digital meter can't be really used. If I took a digital meter into a Bullpen and started checking control voltage on something I'm going to get screwed up readings because of all the magnetism from the transformers and high voltage lines. You don't get that with a analog meter.

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PostPosted: Mon Jan 05, 2009 12:44 pm 
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Joined: Fri Dec 26, 2008 9:40 am
Posts: 2
Location: Missouri
During my apprenticeship in the UK coal industry, I was lucky to see electronics come into the industry during the mid 1960's. At first in face conveyor control, ie signals/lockout and indicator circuits through to solid state face communications.
Then into gate end boxes, (explosion proof) switchgear/contactors, as sensitive earth leakage protection and then O/L circuits.
Progressing to full main trunk conveyor control and telemetry. Through to the automatic skipping equipment in shafts.
We as electricians were responsible for fault finding and repair up to removing "cards or modules" and sending them away for repair to the manufacturers.
As for test equipment, I worked under strict laws forbidding exposing live conductors other than low voltage IS circuits. So we had to rely on our experience, any built in test devices and either an electronic megger, or a metrohm. Later meggers had a 25 volt ac/dc meter position for tests on IS circuits.
My last mine was in Australia, where we had a, SCR controlled DC winch for hauling manriding cars for men and materials up and down the drift. We also had battery mancars and electric loco's, all electronically controlled, we carried out repairs to those.
We were also starting to install "soft start" 1000 volt trunk conveyor starters to our slip ring belt motors to replace the step contactors.


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