3-phase: how to tell amperage/voltage?

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3-phase: how to tell amperage/voltage? Bernard Arnest 05-08-2006
Posted by Bernard Arnest on May 8, 2006, 2:03 am
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Hi,

After an 8-month-long search, I may finally have found a space
on campus for a forge.

For my forge I want a hydraulic press, which = power hungry

The room is shared by a bridgeport mill, a lathe, and a metal
bandsaw, which I'm told run on 3-phase.

I'm new to this. I know that with standard household power, all
outlets are 15amp, unless one contact is turned 90 degrees, and then
you know it's 20amps.

I'll visit the shop again tomorrow or tuesday and examine it
more closely. How do I tell the voltage and amperage of this 3-phase
circuit, so I know how much I can load onto it? The press would
benefit from a 5-10 hp motor, so I need to know if it could handle that
power. How do I find out; are there specific plug types to recognize--
if you even use plugs?



thanks!
-Bernard Arnest


Posted by Roger Shoaf on May 8, 2006, 6:06 am
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A three phase plug is usually a twist plug with 4 prongs.

Also look at the motor data plates on the machine tools. They will tell you
the voltage and if it is single or 3 phase.

Also if it is on campus they probably have an electrician on staff and you
could ask him. You might need a dedicated circuit.

--
Roger Shoaf

If knowledge is power, and power corrupts, what does this say about the
Congress?
> Hi,
>
> After an 8-month-long search, I may finally have found a space
> on campus for a forge.
>
> For my forge I want a hydraulic press, which = power hungry
>
> The room is shared by a bridgeport mill, a lathe, and a metal
> bandsaw, which I'm told run on 3-phase.
>
> I'm new to this. I know that with standard household power, all
> outlets are 15amp, unless one contact is turned 90 degrees, and then
> you know it's 20amps.
>
> I'll visit the shop again tomorrow or tuesday and examine it
> more closely. How do I tell the voltage and amperage of this 3-phase
> circuit, so I know how much I can load onto it? The press would
> benefit from a 5-10 hp motor, so I need to know if it could handle that
> power. How do I find out; are there specific plug types to recognize--
> if you even use plugs?
>
>
>
> thanks!
> -Bernard Arnest
>



Posted by John on May 8, 2006, 9:22 am
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First of all you really need an electrician to look at the room wiring.
I don't want to apear insulting but if you don't know about electrics,
get a professional in.
Do the other room users know you want to put a forge in there? The
forges I've seen (which is relatively few) make lots of nasty black
dust which lathes etc don't like.


Posted by RoyJ on May 8, 2006, 10:52 am
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You really can't tell much from the plugs in the room, there is enough
variation that is will be misleading. This variation is a function of
both local intereptations of NEC as well as conventions used by that
building.

For a very ROUGH approximation, Bridgeports typicaly come with 2 hp 3
phase motors, ditto for a 15" lathe (less and single for smaller 10"
lathe) and 1 hp for a bandsaw (single or 3 phase. This collection of
machines totals around 5 hp of load. Room wiring could be anything
larger than that. Ask the facilities people to meet you in the room,
they can tell you in a couple of minutes what is possible. Be prepared
to need a rewiring job to run a new wire from a convient breaker panel
to your location through (hopefully) an existing conduit. On campus,
this will likely cost as much as the machine you plan to hook up. :(

Your press will not be a welcome neighbor to the machine tools. The dirt
will bother the machines, the noise will bother the users.


Bernard Arnest wrote:
> Hi,
>
> After an 8-month-long search, I may finally have found a space
> on campus for a forge.
>
> For my forge I want a hydraulic press, which = power hungry
>
> The room is shared by a bridgeport mill, a lathe, and a metal
> bandsaw, which I'm told run on 3-phase.
>
> I'm new to this. I know that with standard household power, all
> outlets are 15amp, unless one contact is turned 90 degrees, and then
> you know it's 20amps.
>
> I'll visit the shop again tomorrow or tuesday and examine it
> more closely. How do I tell the voltage and amperage of this 3-phase
> circuit, so I know how much I can load onto it? The press would
> benefit from a 5-10 hp motor, so I need to know if it could handle that
> power. How do I find out; are there specific plug types to recognize--
> if you even use plugs?
>
>
>
> thanks!
> -Bernard Arnest
>

Posted by rigger on May 8, 2006, 12:08 pm
Please log in for more thread options
RoyJ wrote:
> You really can't tell much from the plugs in the room, there is enough
> variation that is will be misleading. This variation is a function of
> both local intereptations of NEC as well as conventions used by that
> building.
>
> For a very ROUGH approximation, Bridgeports typicaly come with 2 hp 3
> phase motors, ditto for a 15" lathe (less and single for smaller 10"
> lathe) and 1 hp for a bandsaw (single or 3 phase. This collection of
> machines totals around 5 hp of load. Room wiring could be anything
> larger than that. Ask the facilities people to meet you in the room,
> they can tell you in a couple of minutes what is possible. Be prepared
> to need a rewiring job to run a new wire from a convient breaker panel
> to your location through (hopefully) an existing conduit. On campus,
> this will likely cost as much as the machine you plan to hook up. :(
>
> Your press will not be a welcome neighbor to the machine tools. The dirt
> will bother the machines, the noise will bother the users.
>
>
> Bernard Arnest wrote:
> > Hi,
> >
> > After an 8-month-long search, I may finally have found a space
> > on campus for a forge.
> >
> > For my forge I want a hydraulic press, which = power hungry
> >
> > The room is shared by a bridgeport mill, a lathe, and a metal
> > bandsaw, which I'm told run on 3-phase.
> >
> > I'm new to this. I know that with standard household power, all
> > outlets are 15amp, unless one contact is turned 90 degrees, and then
> > you know it's 20amps.
> >
> > I'll visit the shop again tomorrow or tuesday and examine it
> > more closely. How do I tell the voltage and amperage of this 3-phase
> > circuit, so I know how much I can load onto it? The press would
> > benefit from a 5-10 hp motor, so I need to know if it could handle that
> > power. How do I find out; are there specific plug types to recognize--
> > if you even use plugs?
> >
> >
> >
> > thanks!
> > -Bernard Arnest
> >

<Your press will not be a welcome neighbor to the machine tools. The
dirt
> will bother the machines, the noise will bother the users.>

Most small hydraulic pumps are not much different from small mills or
lathes when it comes to noise. An air hammer now would be a different
story. Perhaps you meant a coal forge was dirtier? You could always
use a gas fired forge which, again, is not all that objectionable.

dennis
in nca


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