Hi All,
I'm building a small shop that will be fed with a 125 amp 240 volt circuit. I would like to run a large planer in my shop but don't have 3 phase. I was thinking of using a phase converter but i'm not sure how big i can go.
I will have a 40 amp draw on that circuit as my kiln is on it. Most likely less as it will just be the dehumidifier unit not the back up heater (KD250) as i have natural gas heat.
Safely i say i have 60-65 amps to play with.
Iv been looking at some planers that are rated at around 13KW. What other information do i need to get to determine how many single phase amps i will need?
Here's a sizing chart:
https://www.americanrotary.com/products/view/ar-pro-series
13 KW translates to 17 or 18 HP.
I have been looking for a big 3-phase planer but my plans are to convert to tractor PTO.
Hook it up and see, if it pops the breaker, You're drawing to much current. If not, run with it. Just be sure you use wire and breakers that are rated for the load you're pulling.
And wether or not you pull a permit, make sure you meet and preferably excede the building/electrical code in your area.
Home owners policy providers are funny about paying out claims due to half fast slip shawed electrical work.
"Don't try to pull 30 amps through a run of 14 guage wire." That's how you burn the place down.
For a planer like You're talking about, I would use at least a 6 guage copper wire maybe even a 4 guage single strand , pulling all your strands through a steel conduit coming off a 40 amp breaker to a rotery phase converter that acually generates that third leg for genuine 3 phase power.
Don't screw around with a static phase converter for a large machine as you have, it will not run at it's full hp potential.
Spend the extra money ,do it right and you will save yourself a whole world of continuing problems .
Don't skimp on it trying to nickle and dime somthing that you expect to get a life time of service out of.
Remember the old cleche?
There's never enough time to do it right , but there's always plenty of time and money to do it over. Good luck.
I would recommend up sizing your service to 200Amp from the get go as you will find that you will want to add more equipment over time. It is alot cheaper to do it right with enough future capacity than to try to be cheap and chincy and end up with a nightmare on your hands.
I've run rotary phase converters that I've built myself for years. The first was based on a 25 HP 3 phase motor and wasn't even balanced. It ran my 3 phase lathes and mills just fine.
When I got my HAAS CNC lathe, I built another based on a 60HP 3 phase motor and used caps to balance out the legs. This is fed by a dedicated 200 Amp panel. It ran my Mazak Integrex rated at 87 KW, my HAAS lathe, a 400mm Horizontal machining center, and a couple robots with no problems.
In theory, it should be too small. The reality is that the machines are rated as if every motor is started at the same time. It's just not going to ever happen that the main and sub turning spindles, the mill spindle, axis drives and tool changer motors will all start at the same time. In your case the killer is the cold inrush to the motor. Even if your phase converter was too small, you could use a single phase belt drive to help kick start your motor. I did this for years with my smaller phase converter starting a 4 1/2" boring mill.
It's hard to use to big a motor for a phase converter. It's easy to build one too small. The larger motor simply costs a few pennies more per day to run.
My planer is a 30" Whitney, old American iron, and it has a 15 hp motor. I run it, and all the other machines in my shop, using a 20 hp, American Rotary phase converter. Forget the thought right now of using a static converter, if you're thinking that way. It's wasted money, and they are HORRIBLE for 3 phase motors in the long term. I have a woodworking associate who has burned out 3 different motors using them, and he's finally listening to some sense and getting a RPC.
Watch clist for these. There are a lot of people out there that bought a RPC with dreams of grandeur about building a big workshop, only to have it sit in the corner going unused for 5 years before reality sets in. I check craigslist several times a week for old machines, and I see good, used rotary phase converters for sale every single time. I purchased my 20 hp unit, which is a CNC balanced HD unit, brand new, still in the original box and on the pallet, with a brand new, never wired 20 hp Baldor motor for $900.......less than half what they cost from the factory. I see similar deals all the time. Mine works perfectly. It took me about 90 minutes to wire it up to two different circuits.
As far as planers go, depending on what size you are looking for, your current electrical setup is more than adequate to supply the necessary amperage for a decent sized RPC. I have another 10 hp American Rotary phase converter that only requires 32 amps to start and run, IIRC. It was also balanced, and was able to easily start and run a 24" jointer and 36" bandsaw, both with 7.5 hp motors (not at the same time.) Most 24" planers run on 7.5 hp, 3 phase motors, and 18" planers usually run on 5 hp. 3 phase motors. There are always exceptions, but this is what I see most often.
If you check your power supply lines to see what size wire they are, you may be able to add an additional 60 amp or 100 amp sub panel without changing anything. When I built my shop 15 years ago, I thought I was going to need to run new lines from the road to the house. Turned out that the size of the feed wires was the correct size for 400 amp service ( I have 200 amps to the house) and all I needed to do was change the meter out to a bigger one. I then ran 200 amp service to my shop, and it's been operating without incident under heavy load for 15 years.
Your local inspector or a licensed electrician should be able to easily verify what your existing service can be upgraded to, if at all.
I've been running a 40hp phase converter for about 10 years. It runs my vac kilns which are never shut down so it's been running non-stop 24/7 for all of these years without a problem. I used to need to change the capacitance to match the load but I haven't messed with the capacitors for a long time. The reason was that motors run off freq drives would act weird. For example, I have a bridge crane that is driven with a joystick. Sometimes it wouldn't come to a dead stop when it was supposed to. Also, my vac pumps are run off freq drives and when they were supposed to be shut off, they would continue to slowly rotate.
A lot of difference between starting load and running. If you run too close, just make sure other loads are turned off when you start the planer. A lot of folks now use a Variable Frequency Drive instead of a phase convertor. Especially if you are only going to run a single machine.
VFD's are a great choice for smaller hp motors. I've got one for wood lathe, one for a drill press, and one for my 2X72 belt grinder for grinding plane knives.
For a 15 or 20 hp motor, however, they are going to get very, very expensive in a big hurry. For a 15 hp 3 phase motor, you'll need a 30 hp VFD. Price one of those out and you may faint, unless you can find one dirt cheap on the auction site.