Whole Shop And Machine-specific Help For Dunce

I think this should do it. Change the txt filename extension to DXF

Rather than even bother with a control transformer, we'll just bring in a neutral.

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Wow guys, you sure can put things together on the fly! Experience, experience, experience... There is simply no substitute. Okay, so a couple of things. This goes back to my ignorance, and I'm not wanting to side-track the direct discussion here, but a question: I'm going to be installing a 30hp RPC. I'm going to be providing 100amp circuit breaker in my single-phase load center to pass off to the RPC. The RPC will pass that off to a 3-phase load center. Jim recommends a 100amp disconnect with 70 amp fuses. The lathe motor says 40 amps. I'm sure I'm missing something here, as usual, but why 70 amps? I know we're going to be adding more to this than just the 40amps for the motor, but I'm sure this is my ignorance speaking here... I'm not the sharpest tool in the drawer, so if it's not too imposing, can you explain the reasoning here? I'm not trying at all to be difficult or argumentative. I just don't know and wish to better understand.

Jim, as for your tip on the supplier, I will bookmark that immediately. The last tip you gave me(ecompressedair.com) turned out to be a super recommendation. Thanks!

As for lamps, I hear you, but LEDs and fluorescents(particularly the former) tend to trigger severe migraines for me. Something to do with the wavelength of the light, I think. I won't be able to get around using fluorescents in the shop, but to aid with that, particularly in the workshop, I'll add filters to them. LEDs are for some reason very quick to trigger the migraines. When they announced the coming end to 100w incandescent bulbs a few years ago, I bought like 3 cases of them. Enough to last my lifetime and beyond. I'm all for saving energy, but compact fluorescents drive our dogs nuts. They apparently emit some high-frequency hum/buzz that makes them crazy. So we stay away from fluorescents in the house altogether.

Nice diagram. One of the things I thought about was lights, specifically lit switches. On the front panel of the lathe, there are switches for On, Off, Lamp, and Coolant Pump. There is also supposed to be a domed indicator light that shows the lathe is powered-on/running. I wonder if it would be useful to use lit switches for lamp and pump. (I know that seems a bit redundant in the case of the lamp, but my reasoning is that if the switched circuit is on, and the indicator tells me that, but the lamp isn't lit, it kind of tells me what the problem is. (Of course, this is overkill...LOL) As for the pump, however, going hard of hearing as I am, an indicator light helps me.

When you say "bring a neutral," you're meaning that we'll need the neutral in the 3 phase panel. Do I bring the neutral directly over from the single phase panel to the 3 phase panel?

Do you view DXFs in autocad?

Thanks!

Mark
 
Wow guys, you sure can put things together on the fly! Experience, experience, experience... There is simply no substitute.

I've done this a time or two :grin:

Jim recommends a 100amp disconnect with 70 amp fuses. The lathe motor says 40 amps. I'm sure I'm missing something here, as usual, but why 70 amps?

Normal fusing for a motor is about 175% of the motor maximum load current. Having said that, the breaker in your 3 phase panel should be adequate. A 60 amp unfused disconnect at the lathe would be OK. Or you could just use the 3 phase panel breaker as the disconnect. OK for home shop, but would not meet code in a commercial environment.

Nice diagram. One of the things I thought about was lights, specifically lit switches. On the front panel of the lathe, there are switches for On, Off, Lamp, and Coolant Pump. There is also supposed to be a domed indicator light that shows the lathe is powered-on/running. I wonder if it would be useful to use lit switches for lamp and pump.

We can add lighted switches, no problem.

When you say "bring a neutral," you're meaning that we'll need the neutral in the 3 phase panel. Do I bring the neutral directly over from the single phase panel to the 3 phase panel?

Yes, just pass the neutral through from the single phase panel, through the 3 phase panel and over to the lathe. In a commercial environment this is not normally possible, but since you are starting with single phase it makes the most sense.

Do you view DXFs in autocad?

You can use any DXF Viewer, but yes, this was generated in AutoCAD 2000.
 
Rather than pulling a neutral thru your 3-P box, I've run a 120v line to the control box separately from your 3-p wire run. In fact, you can run it along with your 3-p wire pull if you like. My last lathe I bought was wired for 440v and two separate wires were run to provide 120v for plugs and light. The contactor is set up to run on either 220v or 440v, just by changing jumpers on the coil. So I guess either way works as long as you don't mix it up with your green ground wire. Just remember to fuse a line off of the main line coming into your box for control voltage and light. For accessory plug, mount a 4-plug box up on the wall behind where your lathe will be set up and make sure it is GFIC protected. That goes for all plugs in your shop. It's considered outside according to NFA-NEC. Ken
 
That'll work also. I did just that for my mill, brought in the 240 single phase for the spindle VFD and another pair for the 120V plug on the wall in the same conduit but on a separate breaker. The VFD is hardwired in the box. Then put a quad plug on the wall. I plug in all of the control system into that.
 
That'll work also. I did just that for my mill, brought in the 240 single phase for the spindle VFD and another pair for the 120V plug on the wall in the same conduit but on a separate breaker. The VFD is hardwired in the box. Then put a quad plug on the wall. I plug in all of the control system into that.
A handle tie would be a good idea.
 
Sorry folks, been on the road the last few days.
I've done this a time or two :grin:

So I've gathered.
Normal fusing for a motor is about 175% of the motor maximum load current. Having said that, the breaker in your 3 phase panel should be adequate. A 60 amp unfused disconnect at the lathe would be OK. Or you could just use the 3 phase panel breaker as the disconnect. OK for home shop, but would not meet code in a commercial environment.

Ah, that makes more sense. Now I get the 70 amps... I'm thinking 40amps is enough, but you're saying 70 = 175%. Got ya...

We can add lighted switches, no problem.

Good deal. A few bells/whistles never hurt anybody.

Yes, just pass the neutral through from the single phase panel, through the 3 phase panel and over to the lathe. In a commercial environment this is not normally possible, but since you are starting with single phase it makes the most sense.

That makes sense. Shouldn't take much to do so.

You can use any DXF Viewer, but yes, this was generated in AutoCAD 2000.

Okay, thanks. Didn't have anything handy to open it. Somewhere, I've got an old copy of AutoCad.

Rather than pulling a neutral thru your 3-P box, I've run a 120v line to the control box separately from your 3-p wire run. In fact, you can run it along with your 3-p wire pull if you like. My last lathe I bought was wired for 440v and two separate wires were run to provide 120v for plugs and light. The contactor is set up to run on either 220v or 440v, just by changing jumpers on the coil. So I guess either way works as long as you don't mix it up with your green ground wire. Just remember to fuse a line off of the main line coming into your box for control voltage and light. For accessory plug, mount a 4-plug box up on the wall behind where your lathe will be set up and make sure it is GFIC protected. That goes for all plugs in your shop. It's considered outside according to NFA-NEC. Ken

I wondered about the best approach and where GFCI should be used in the shop. Simple is better for my thick skull.

That'll work also. I did just that for my mill, brought in the 240 single phase for the spindle VFD and another pair for the 120V plug on the wall in the same conduit but on a separate breaker. The VFD is hardwired in the box. Then put a quad plug on the wall. I plug in all of the control system into that.

So basically, the 240 3phase to power the lathe motor, but we're just going to do a separate circuit altogether for controls/accessories. That actually makes good sense. Does this mean I'll need like a "master power on/off" for the 120v control circuits?

A handle tie would be a good idea.

John, thanks, where goes the handle tie?

Thanks all!
 
John, thanks, where goes the handle tie?
It ties the handle of the breaker protecting the spindle circuit to the handle of the single-pole breaker protecting the 120V aux circuit so that you cannot turn off one without turning off the other.
 
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John, I know what a handle tie is. I just wasn't understanding where.,. If my 3 phase is in one panel, my single phase in another... Or am I missing something again? Sorry...

Mark
 
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