Phase converters.

[Brad Seubert]

I'm sure this has been covered many times but I think my question is more specific than I am finding answers to by searching.

I have been looking for a jointer planer combo machine in the 12" range. I recently came across a 20" felder for a decent price that I am considering. It has a three phase 7 1/2 horse motor.

My garage shop has a 60 amp subpanel. Do I even have enough power to run this thing and lights and dust collector?

If I do have enough power what would be the best way to get three phase for that motor? Rotary? Vfd? Where's a good please to buy from. I'd like an idea how much this will cost.

[Brian Backner]

I'n no electrician, but a good rule of thumb for single phase electric motors is 10amps/hp at 120, or 5amps/hp at 240. So, not counting startup surge, you'd need about 35-40 amps of your 60 amp subpanel.

VFD in that size to convert to three phase would be expensive as you'd have to markedly upsize it. A static phase inverter might be a better choice as they're cheap, but you do take a hit in efficiency and loss of hp. A rotary phase convertor would be best though you would need at least a 10hp idler motor and possibly a 15. You might also consider just replacing the existing motor with a single phase one. One that size isn't cheap, though they do show up on CraigsList from time to time. I got a 10hp single phase Baldor for $200 last year, so they can be found.

If you decide to go with a rotary, there are tons of websites all across the web to help in designing/building one (commercial ones can be pricey). I attempted to load a pdf of the Fitch William convertor, but it is too large a file. You can either Google it, or if you PM your email I can send it directly. I also found a PDF on static inverters.

[Dennis Ford]

Starting that motor is likely to be a problem, replacing with a single phase motor would be better IMO if the machine is belt driven. If it is direct drive, consider what you would do if the motor failed.

[Bruce Page]

I have a static converter on my 5hp engine lathe and a 2hp milling machine, both start up just fine. I've been using this setup for over 20 years.

[Paul Murphy]

I have a 7.5hp single phase compressor that required a 60A breaker, so you might be up against the limits of your wiring.

Many VFD's have a "soft start" adjustment, and I've read that there are also "soft starters" for folks already owning a rotary phase converter. In your situation I think without something controlling your inrush current you will overload your 60A panel.
http://www.lselectric.com/soft-starters-vs-variable-frequency-drives/

Also, the VFD's and phase converters for motors above 3hp climb quickly in price, so look at the complete package price. You should talk your situation over with a specialty business such as these:
http://www.factorymation.com/
http://www.wolfautomation.com/

[Brad Seubert]

That seems to confirm what I thought. It would be pushing the limits of my current electrical system and add a decent dollar amount to get this thing to run on single phase.

Guess I'll keep looking. Thanks guys!

[Allan Speers]

A rotary phase convertor is far better than a static one, as the latter will coast you 1/3 or your horsepower.

Price will be very high, so yes watch CS.

-------------------------

IMO, the cost of VFD's today makes the thought of a huge RPC a little antiquated. A dedicated VFD offers several advantages:

Only 1 on-off switch

Easy to add E-stops

Soft-start - In your case, this might be a life-saver, since inrush current could cause trouble with your 60a mainbreaker.

Dynamic braking

Motor reverse

Vari-speed

Extra motor overload protection.

Protection from accidental turn on, as with a Mag starter

No need for a GFI outlet.

---------------------------

Go to http://www.factorymation.com for the best prices on the planet. Then call and talk to "Dianne" for lots of extremely good tech advice.



update: I see Paul already beat me to it. Well, it's still all correct !

[Anthony Whitesell]

Since we are talking phase converters, the logical assumption is the supply is 220VAC single phase. As stated the motor in question is 7.5hp 3 phase (voltage not given).

When I was looking for single phase in-three phase out VFDs, I thought I read something about the highest HP VFD available for this application is 2HP. Is there available a 220VAC single phase in-three phase out 7.5HP VFD available?

[David L Morse]

Since we are talking phase converters, the logical assumption is the supply is 220VAC single phase. As stated the motor in question is 7.5hp 3 phase (voltage not given).

When I was looking for single phase in-three phase out VFDs, I thought I read something about the highest HP VFD available for this application is 2HP. Is there available a 220VAC single phase in-three phase out 7.5HP VFD available?

Not cheap, but, yes: http://www.driveswarehouse.com/p-2124-pc1-75.aspx

[Mike Heidrick]

Man a 20" Felder would so be worth a panel upgrade if needed!

[Brad Seubert]

Man a 20" Felder would so be worth a panel upgrade if needed!

I would love to have it....but I would be stretching my budget already just to purchase the machine, and then I would still have to buy a phase converter and upgrade that power to my house. I only have 100amp main coming into my house from the power company. At the time I had the subpanel put in they said 60 amps for the subpanel was about the most they could do from a 100 amp main.

[Bruce Page]

I upgraded to a 200amp panel last year when I had refrigerated air installed. The panel upgrade was $1500. That included running a new 50amp line to my shop sub panel.

[John Lankers]

Check out this site http://www.temcoindustrialpower.com/product_selection.html?p=CFW10_Product_Selection
You should be fine, unless there is some other big draw on the panel besides planer and dust collector. I have a 60 Amp sub panel with almost identical power draw and it's all working just fine. Having said that, if you think you can shove a 20" wide oak plank through the planer and hog off a 1/4" think again, just use common sense. You can't compare an air compressor to a planer or table saw, the compressor always has to start under heavy load - the jointer/planer not. Btw. keep the wiring short and heavy.
I'd bend over backwards to get that machine.

[Rick Fisher]

60 amp single phase should be enough to run a 7.5hp PH-3 motor .. 3 phase motors aren't as in-rush sensitive as single phase, and the Felder will ( should ) have a Star - Delta starter.. The initial inrush shouldn't be an issue for a second or so ..

Technically 60 amps should provide you with 34 amps of PH-3 .. but it won't .. so figure 27-28 amps.. A 3 phase 7.5hp motor will draw maybe 20 amps at full load ..

[Brad Seubert]

Check out this site http://www.temcoindustrialpower.com/product_selection.html?p=CFW10_Product_Selection
You should be fine, unless there is some other big draw on the panel besides planer and dust collector. I have a 60 Amp sub panel with almost identical power draw and it's all working just fine. Having said that, if you think you can shove a 20" wide oak plank through the planer and hog off a 1/4" think again, just use common sense. You can't compare an air compressor to a planer or table saw, the compressor always has to start under heavy load - the jointer/planer not. Btw. keep the wiring short and heavy.
I'd bend over backwards to get that machine.

So a static converter like this would work? Seems like I am missing something, this seems to cheap?
http://www.temcoindustrialpower.com/products/Static_Phase_Converters/PC0013.html

I have been watching it on craigslist for awhile and have been thinking about making a lowball offer as that is the only way I could afford it. I imagine it is a tough item to sell since its 3 phase, so I was hoping I could get a deal on it.

[John Lankers]

[QUOTE=Brad Seubert;2432839]So a static converter like this would work? Seems like I am missing something, this seems to cheap?
http://www.temcoindustrialpower.com/products/Static_Phase_Converters/PC0013.html



Brad, I have a Felder KF 700S Pro on order with two 7.5 hp 3 phase 230 Volt motors. My garage workshop is wired for single phase 230 Volt 60 Amp. The machine is being built as we speak in Austria and will then be shipped to Winnipeg, MB where the Felder dealership will have the 3 phase inverter installed and matched (programmed ?) to the machine after which it will be CSA certified (mandatory by law). The inverter install is Felder certified and fully warrantied.
3 phase motors start easier than single phase motors because of the star/delta switching. 7.5 hp motor only means the motor is able the deliver the full 7.5 hp not that it does it all the time. We have a hot tub with three 5 hp pumps and electric heat, when our electrician hooked it up I asked him to measure the Amp draw with everything on - 38 Amp max.
I could get in touch with Felder on Monday and get all the details for you if you're interested.

[Brad Seubert]

John thanks for the info. I guess I need to decide if I have the room for this in my shop and then talk to the seller and how flexible he is on the price. I really want the thing but can only justify it if I get a great deal on it.

Thanks for the offer to talk with felder, Lets wait till I make an offer on it before you talk to felder

[M Toupin]

So a static converter like this would work? Seems like I am missing something, this seems to cheap?\http://www.temcoindustrialpower.com/products/Static_Phase_Converters/PC0013.html

That's a STATIC converter and will only give you about 1/2 the rated motor hp on a delta wound motor or 1/2 rated hp on a wye wound motor. Not to mention it's not good for the motor. A static converter just starts the motor by inputting single phase 220v and shifting the phase via capacitors to get the motor turning. The capacitors then drop out and run the motor on single phase. Think taking your 6 cylinder car and pulling out 2 of the spark plugs so it runs on 4 cylinders. As you can probably imagine, it's not good for the motor especially a motor constantly under heavy load such a a planer for extended periods.

So, you're options are:

1. Swap out the motor for a single phase motor - A 7.5hp motor will run Somewhere north of $1000 for a decent motor. You'll also need new wiring to handle the increase amperage required by single phase and a new starter or at least new heaters if they're changeable.

1. Static converter - loose 2/3-1/2 the rated hp and not good for your motor. So ask yourself, when the 7.5hp motor burns up and has to be replaced is it really worth it to save a few $$ in the beginning?

2. Rotary phase converter - will give you the option to add more 3ph machines down the road. A 10hp commercial made runs $1000ish or a shop make can be built for very small $$ depending on how basic you want to go. (check out Practical Machinist forum Converter/VFD forum for plans). Up side is it's pug and play, the existing wiring, starter and controls will work just as if you're hooked up to the power pole.

3. Variable Frequency Drive (VFD) - Generally recommended to dedicate a to single machine. Single phase input models get expensive above 3hp and a 7.5hp model will run you at least $1000 new but you might be able to find a used one for less. If you go used just be careful the model actually works with 3ph. Some 3ph input listed models will run on single phase but need to be de-raated by %50 so if it's a 3ph input (with no phase lost detection) you'll need a 15hp model.

4. Digital phase converter - such as the Phase Perfect (10hp model runs $3,300) creates 3ph power from single phase input much like a VFD without all the fancy options.

At the end of the day there's several different options to power it but only you can decide what's best for your particular situation and what you think the future might bring.

Mike

[John Lankers]

I apologize, I wasn't clear in my original post.
I just have said: "check out this website to get an idea of what's out there". This inverter http://www.temcoindustrialpower.com/products/Static_Phase_Converters/PC0013.html definitely inadequate.
As I said before I would have to check back with Felder to find out exactly which make, model they install in their machines (they promised me it will work just fine on 40 Amp single phase). I can't post the price since they had an aggressive sale at the time.
I apologize again for causing confusion.

[M Toupin]

would have to check back with Felder to find out exactly which make, model they install in their machines

John, As I said before, that's a STATIC converter and does nothing more than start a 3ph motor and run it on single phase with 1/3 to 1/2 the original hp power loss.

While I'm too lazy to look it up but I would be completely blown away if Felder uses a static converter on their machines. It makes absolutely no sense to even consider using a static converter to single phase a 3ph motor when they could use the proper motor (and full hp) from the beginning. I'm just left wondering why? Paying for a 7.5hp machine and single phasing it so it puts out 3.75hp is it bit odd to me when I could just buy the 4hp 1ph version for less and have more available hp.

Mike

[John Lankers]

John, As I said before, that's a STATIC converter and does nothing more than start a 3ph motor and run it on single phase with 1/3 to 1/2 the original hp power loss.

While I'm too lazy to look it up but I would be completely blown away if Felder uses a static converter on their machines. It makes absolutely no sense to even consider using a static converter to single phase a 3ph motor when they could use the proper motor (and full hp) from the beginning. I'm just left wondering why? Paying for a 7.5hp machine and single phasing it so it puts out 3.75hp is it bit odd to me when I could just buy the 4hp 1ph version for less and have more available hp.

Mike

Mike, with all due respect,
I pointed Brad to the website that shows several dozen options, not as you are suggesting to a specific inverter.
Neither did I say Felder would install this particular inverter, only that they would install an inverter and I would have to call them on Monday to find out what make, model and specs.
The reason I chose a KF700 with two 7.5 hp 3 phase motors was: a) I am planning to upgrade to a shop with 3 phase power in the future and can then disconnect the inverter, b) a 4 hp motor would be sufficient for the saw but not for the shaper and therefor the 7.5 hp option is a must have for me and c) if I ever decide to sell the machine it can be configured as single phase or 3 phase.
What I know at this time is that the inverter will be sized for the 7.5 hp motors!
John

[Rollie Meyers]

In most cases a VFD for a motor over 3 HP will have to be derated 50% & able to have phase loss protection disabled, meaning a 15 HP VFD would be required, plus the wiring has to be the FULL rating of the drive, this makes things a bit more difficult when dealing with a limited amount of available power. Per 430.122(A) the drive needs have the circuit conductors rated for 125% of the rated input current.

[Andy Booth]

60A subpanel off of a 100A main to the house seems marginal for this application. Depending on the size and length of wiring from the utility transformer I would be worried about blinking everything in the house every time I started the beast.
It has been my experience that major appliances like Refrigerators do not like voltage sags.
So technically possible, but not sure it is practical.