[Wayne Perry]

purchased a farmette that includes a machine shop wired to power several 3 phase machines (lathe, milling machine, etc.). It has a 3 phase generator/converter that you kick on to use the machines. I'm converting the space to a wood shop, replacing the machinery with single phase tools. Question: Would there be any advantage to modifying the generator to power the single phase equipment to lessen the load on the 150 amp supply coming from the house?

 

[joed]

Depending on the voltage you may not need to modify it. Single phase devices can run off three phase supply if the voltage is correct. You just don't use all three phases. You use either one phase to neutral or two phases.

 

[rjniles]

A phase convertor is inherently inefficient. Eliminating it will lessen the load on the single phase feeder.

 

[AllanJ]

Is the generator run by gasoline, propane, natural gas, fuel oil, or electricity?

If by electricity drawn from the aforementioned 150 amp feed then simply wire up the new tools and equipment to the 150 amp subpanel, possibly reusing stretches of 3 phase wiring decommissioned from the 3 phase system. You would not be increasing the load on the feeder for the same amount of total machine horsepower. WHen nothing remains connected to the 3 phase generator decommission the latter.

 

[seharper]

It sounds like your shop has single phase power, and then, the last guy got a 3-phase converter so he could run 3-phase tools.

And you have no interest in 3-phase tools.

Therefore, to you, the phase converter is of no interest whatsoever. You should completely ignore it, and simply wire all your single/split-phase tools to the panel in the way you are familiar.

If you are trying to be a little cheap, and reuse the 3-phase panelboard and wiring for single-phase tools, that is probably possible. Depending on the wiring of the phase converter, even with the converter off, 2 of the phases may be hot. That’s easy peasy, then; just use those 2 phases.

If it’s not that simple, then get us pix of the converter and wiring, and we can figure out how to carefully dismantle and remove the phase converter. You can take an axe to it if you really want to, but the thing is worth real money, so I’d dismantle it with an eye toward reuse or honest resale (so you can tell the Craigslist person “I carefully removed it complete and intact”, not “here’s a pile of parts that used to be a phase converter”).

Also, keep in mind, having 3-phase at your shop means you can buy tools at deep discount on Craigslist from all the pro-am homeowners who bought a 3-phase tool and thought getting 3-phase power would be easy.

 

[Wayne Perry]

Many thanks for the info!! As to my major question re: any advantage to keeping the 3-phase converter, it's pretty clearly "no." None of my woodworking tools are 3-phase, so I'll just pull out the converter and sell it. Currently, there are 2 sub-panels; 1 for all the 3-phase circuits and then the other for the lights, receptacles, and the 220V air compressor. Since the branch wiring is already around the shop, I think I'll just re-do the 3-phase panel so that I end up with dedicated 120V 20A circuits for my big tools around the shop.

Thanks to your info and suggestions, problem solved and I've now got a plan.

 

[Wayne Perry]

By the way, in case you're interested, I put 2 pics in my album of the set-up. It looks like it was done the right way originally, so removing the converter and re-wiring the 3-phase panel shouldn't be a big problem. Thanks again!

 

[Missouri Bound]

When you say "converting the space to a wood shop" do you mean for yourself or a commercial shop? If it's just you making sawdust you probably won't need to do anything except forget the phase adder/converter.
Sell the generator and buy some tools with the profit.

 

[Wayne Perry]

Just making sawdust. I'll take your advice. Thanks.

 

[Wayne Perry]

Getting ready to disconnect my 3 phase converter. I want to make sure I do it safely.

I have some pics in my album. I'm fine with basic connects/disconnects in normal circumstances, but here I don't know if I need to discharge capacitors or take any other steps. The only thing I'm doing right now is disconnecting the converter from the system so that I can sell it. It works fine...just had it running yesterday with no issues.

 

[seharper]

That thing is a *rotary* phase converter! Wow, what a classic bulletproof machine. I hope you find somebody who’ll give it a loving home. I’d come get it myself if it wasn’t for COVID and probable distance.

Suffice it to say, the machine stores energy in the rotating shaft, not capacitors. Just de-energize the whole garage (I presume the left panel in your album is a subpanel) and give it 20 minutes, and you should be safe.

 

[Wayne Perry]

Many thanks, seharper, for the great info and huge advice!