Amp Dial on my Zeiss Power Supply

75RR · Post by **75RR** » Sat Apr 29, 2017 2:15 pm

They were in a post by Choronzon, just above the one I partially quoted him in. He must have deleted it. The other quote I used was his as well.

Those two interpretations seem consistent.

Glad to hear that. Though running the bulbs at max watts would make for a very short life. Just 100 hours in the case of the 60w tungsten.

mawyatt · Post by **mawyatt** » Sat Apr 29, 2017 2:17 pm

You can use a very cheap DVM to read the current to 10A, either AC or DC. The AC current is interpreted as the RMS value of the absolute value average current. What this means is that for a normal sinusoid (your 120V or 220V wall AC supply) the RMS value displayed is correct within a the accuracy of the meter. If the current becomes non sinusoidal then the displays are in error. For example a square wave has an peak, absolute value average and RMS all the same value, as does DC.

The relationship between peak. absolute value average and RMS for a normalized sinusoid are 1, 0.637 (2/pi) & 0.707 (1/root2).

The nice thing about a DC source is they very simple and cheap, and easily controlled.

Best,

Mike

75RR · Post by **75RR** » Sat Apr 29, 2017 2:24 pm

You can use a very cheap DVM to read the current to 10A, either AC or DC.

Funny you should say that, as I do in fact have a very cheap multimeter. ;)

Will post a follow up when I finally get to meet the Power Supply. Thanks all!

rockycarter · Post by **rockycarter** » Sat Apr 29, 2017 5:47 pm

Rudix
The 240V won't be 3 phase, it would be normal single phase as used in EU and here in South Africa. Not really more dangerous than 110V, other than packing more "kick"!

3 phase would be 380V but it is only used on heavy electrical equipment.

Looks like a great power supply!

The best thing to do with the output voltage would be to connect a V meter across the output, and under load record the relationship between V and A. Since your resistance is both unknown, and it will change as the A's change (lamps do not have a constant resistance as voltage changes) it is not easy to apply a simple formula to work out the relationship

wow i understand your power system thank you for the information Rudix that is a very dangerous system to work on open Delta. north America power system is the star system everything goes to the neutral.

Rudix · Post by **Rudix** » Sun Apr 30, 2017 1:30 am

rockycarter wrote:Rudix
The 240V won't be 3 phase, it would be normal single phase as used in EU and here in South Africa. Not really more dangerous than 110V, other than packing more "kick"!

3 phase would be 380V but it is only used on heavy electrical equipment.

Looks like a great power supply!

The best thing to do with the output voltage would be to connect a V meter across the output, and under load record the relationship between V and A. Since your resistance is both unknown, and it will change as the A's change (lamps do not have a constant resistance as voltage changes) it is not easy to apply a simple formula to work out the relationship

wow i understand your power system thank you for the information Rudix that is a very dangerous system to work on open Delta. north America power system is the star system everything goes to the neutral.

Everything also goes to neutral on our system, the only difference is that there is an extra earth line added, in fact making it far safer than the american system! The earth is not actually part of the supply, it is just there to earth the chassis/frame in case there is a short it goes to earth so that the chassis/frame does not become alive.

The 3 wires of our system are live, neutral and earth, nothing to do with 3 phase where as you note you work on delta and you have extra precautions to take as equipment on different phases can have a lethal potential difference between them if not designed to take that into account.

By law there is then also and "earth leakage" trip on the local distribution board, if there is a short that goes to earth it will trip and disconnect the feed.

In many countries (mostly EU) selling 2 wire US system based appliances are prohibited as they are actually considered unsafe!

Anyway, not important as the power supply under discussion will be perfectly safe.

Rudi

75RR · Post by **75RR** » Sun Apr 30, 2017 2:55 am

Anyway, not important as the power supply under discussion will be perfectly safe.

Thanks for the vote of confidence in the PS - well on the safety front anyway.

Pau · Post by **Pau** » Sun Apr 30, 2017 5:42 am

Because to use it in Spain you'll need to change the plug (or use one ugly adapter) and old wires like the one at your power source are unsafe because the isolator deteriorates, a good idea is to replace it for a surplus computer cable with Schuko european plug and connect the earth wire to the chassis.

By the way Pau, I never asked your permission to move to Spain, hope you do not mind!

I have no competences in immigration nor customs, and we are not saturated of good amateur microscopists...so for my part Welcome!

75RR · Post by **75RR** » Sun Apr 30, 2017 6:50 am

Because to use it in Spain you'll need to change the plug (or use one ugly adapter) and old wires like the one at your power source are unsafe because the isolator deteriorates, a good idea is to replace it for a surplus computer cable with Schuko european plug and connect the earth wire to the chassis.

Very useful tip - will be following it!

I have no competences in immigration nor customs, and we are not saturated of good amateur microscopists...so for my part Welcome!

Thanks :)