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Dr. Dark Current

Fri May 08 2009, 05:58AM

Registered Member #152 Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384

Kizmo wrote ...

(current ballast will cause huuuge drop in input voltage -> should be 50kV with proper ballast)

Isn't that what it should do? If ballast did drop no voltage, well, then it would not ballast!

If you think magnetizing current is dropping the open circuit voltage, I wouldn't think so, these distribution transformers are designed with a huge overhead when it comes to core saturation...

Kizmo

Fri May 08 2009, 01:11PM

Registered Member #599 Joined: Thu Mar 22 2007, 07:40PM
Location: Northern Finland, Rovaniemi
Posts: 624

Dr. Kilovolt wrote ...

Kizmo wrote ...

(current ballast will cause huuuge drop in input voltage -> should be 50kV with proper ballast)

Isn't that what it should do? If ballast did drop no voltage, well, then it would not ballast!

If you think magnetizing current is dropping the open circuit voltage, I wouldn't think so, these distribution transformers are designed with a huge overhead when it comes to core saturation...

Well im not sure but i measured idle sec. voltage and it was 180-195V (230V)

Under load it drops below 100V

Avalanche

Fri May 08 2009, 07:24PM

Registered Member #103 Joined: Thu Feb 09 2006, 08:16PM
Location: Derby, UK
Posts: 845

Hazmatt_(The Underdog) wrote ...

Yea we should bring back old school lacing...

I'll pass on that

the unit below is one of a roomful of similar units, which I am repairing at the moment. All have different faults and I have used probably over 150 zip ties in the last week putting the wiring back... If I had to relace all these buggers I would be going completely nuts by now

Having said that, one of the wiring looms on the PCB is laced - and that's the only one I haven't had to touch yet!

Robert2

Fri May 08 2009, 09:51PM

Registered Member #1773 Joined: Tue Oct 21 2008, 06:56PM
Location: Poland
Posts: 93

My new baby ;]

Hon1nbo

Sat May 09 2009, 11:41PM

Registered Member #902 Joined: Sun Jul 15 2007, 08:17PM
Location: Pacific Northwest USA
Posts: 1042

A lightning photograph I took/enhanced... I used my Casio EX-FH20 High Speed Camera @ 210FPS to get a basic video (which was not very smooth) but i then merged several frames for said video to get this:

1241912503 902 FT6000 Lightning Intergrated 03 Copy 1

Renesis

Sun May 10 2009, 01:57AM

Registered Member #2028 Joined: Mon Mar 16 2009, 08:13PM
Location: Norway
Posts: 319

I just spent two weeks working as an in-turn at a big-ass paper factory. An interesting experience, and i'd love to do it again!

I feel kinda bad for not taking more pictures, i really do. I had a busy schedule, and I also forgot my camcorder AND digital camera at home, and i hate myself for that

But but i got time to take a few, with my cell phone that is, and here they are.

Vaccum pump, tandem centrifugal fan style. That asynchronous induction motor is *only* 1500kW.

Da Wood Chipper! The chipper disk holding the knives is visible in the up-right corner (it is shut off for maintenance). That disk is 4,5m wide, and driven to 500rpm by the 4 motors, each at 375kW. A 4m long trunk, two feet wide is chopped up in under two seconds! That is an astonishing sight!

This room is hot and noisy! That odd container is a huge motor, and they have about 15-20 of these. They run the paper mass mills that tear the woodchips into individual wood fibers. The third pic is the two "millstones" from one of them being overhauled.

The process involves a lot of hot water and steam. Some of the steam is reused and turned back into electrisity in this 8MW turbine. They burn bark to heat the process water.

While im at it, here are two pics without any relevance at all:

Snapshot from my visit at the candy factory a few months back.

At least one of them is mine.

Steve Conner

Sun May 10 2009, 04:31PM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

Renesis, was this the Norske Skog paper mill? A guy from our research group was at Norske Skog last autumn, and he was doing partial discharge measurements on the big multi-megawatt motors that drive the pulp grinders. The pictures he brought back looked identical to your "odd container", so I'm going to guess that it might be the same place.

Renesis

Sun May 10 2009, 07:06PM

Registered Member #2028 Joined: Mon Mar 16 2009, 08:13PM
Location: Norway
Posts: 319

Renesis, was this the Norske Skog paper mill? A guy from our research group was at Norske Skog last autumn, and he was doing partial discharge measurements on the big multi-megawatt motors that drive the pulp grinders. The pictures he brought back looked identical to your "odd container", so I'm going to guess that it might be the same place.

That's right Steve. When the last two of these pulp mills was installed, they were the biggest of their kind in the entire world. The other older mills are slightly smaller, the smallest are 8,5MW if i remember correctly.

Dr. Drone

Mon May 11 2009, 06:29PM

Registered Member #290 Joined: Mon Mar 06 2006, 08:24PM
Location:
Posts: 1673

Mads Barnkob

Mon May 11 2009, 08:17PM

Registered Member #1403 Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968

Just bought today, almost a steal, 40 euro for a 3x6A variac :D

Good size for a bench experiment supply, it can push about 4200W

I am not sure its 6A, but its atleast 6A.

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