Re: [CAD_CAM_EDM_DRO] Re: Transformers

Wally,

Our Flash Butt Welder secondary transformer is 140,000Amps at 4 volts
or 560KVA. In the weldering process this transformer is placed in a dead
short across the work piece (hence the term flash). The incoming service
is 480VAC /3P @ 800 Amps. This transformer is controlled and switched by
by 12 Water Cooled SCR's and is connected to a 30 Ton Water Chiller to
prevent a meltdown..

Two other Heat Treating machines have 1300 KVA Transformer Tanks and 100
Ton Water Chillers.

gary

cnc_4_me wrote:

>--- In CAD_CAM_EDM_DRO@yahoogroups.com, "John Stevenson" <john@s...>
>wrote:
>
>
>>Transformer shouldn't be a problem as we can get custom ones wound
>>
>>
>here with not a lot of problem.
>
>
>>I have a nice one here that outputs 33,000 volts at 5 amps. Is
>>
>>
>California looking for a new electric chair ?
>
>165,000 watts or 165Kw. What in the word do you do with it and were
>would you get enough power to use it!!!
>
>Our houses in the USA typically have a 220v at 200 amp service.
>
>44,000 watts or 44Kw.
>
>Wally
>
>
>
>--- In CAD_CAM_EDM_DRO@yahoogroups.com, "John Stevenson" <john@s...>
>wrote:
>
>
>>>Hi John
>>>
>>>Just a couple thoughts...
>>>
>>>If 20 amps is your maximum peak current per motor you would
>>>
>>>
>certainly
>
>
>>>want to have that capability to prevent nuisance tripping in full
>>>accel 3-d diagonal moves.
>>>
>>>However, depending on the machine, average current requirements
>>>
>>>
>will
>
>
>>>probably
>>>be much less. In my large low friction router avearage cureent is
>>>
>>>
>less than
>
>
>>>one quarter
>>>the peak capability.
>>>
>>>So I rate the transformer accordingly. The supply capacitor can
>>>
>>>
>deliver the
>
>
>>>full current for short periods just fine...like a fast ramp up or
>>>
>>>
>ramp down.
>
>
>>>I can calculate the cap size requirements but I must know a bit
>>>
>>>
>about the
>
>
>>>machine dynamics.
>>>
>>>One other thought I would offer...if individual motors are fused
>>>
>>>
>and only
>
>
>>>one
>>>fuse blows, the others will perhaps keep going resulting in an
>>>
>>>
>unforseen
>
>
>>>path
>>>and a possible crash scenario. The estop system must be such that
>>>
>>>
>if any one
>
>
>>>axis
>>>Malfunctions all axes stop. A stop on following error or similar
>>>
>>>
>system can
>
>
>>>do this.
>>>
>>>As far as transformers for UK use I am not sure. Custom toroid
>>>
>>>
>kits with a
>
>
>>>pre-wound primary
>>>and customer wound secondary (about 1 volt per turn) are commonly
>>>
>>>
>available.
>
>
>>>Les
>>>
>>>
>>>
>>Les,
>>This is for a Bridgy Series l conversion using 110volt treadmill
>>
>>
>motors as 100 volt servos.
>
>
>>There will be no 3D moves only two axis will be cutting at any one
>>
>>
>time, all my work is 2 - 1/2D.
>
>
>>Good point about the fuses, This can be accomplished by power on
>>
>>
>relays wired into the stop circuit.
>
>
>>Transformer shouldn't be a problem as we can get custom ones wound
>>
>>
>here with not a lot of problem.
>
>
>>I have a nice one here that outputs 33,000 volts at 5 amps. Is
>>
>>
>California looking for a new electric chair ?
>
>
>>
>>--
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>>
>>
>21/04/2005
>
>
>>
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>
>
>
>
>
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