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Thread: How many tools can I run on a 3 phase power converter?

  1. #1
    Join Date
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    Question How many tools can I run on a 3 phase power converter?

    Oh man really thinking about this hurts my head. I do have a Pro electrician friend coming by, but trying to get some pointers first. I have also have trawled through the forum to get some research tips on this very important topic. Currently I a Single phase connection in my house/garage. I have a 220v outlet for the dryer available inside the garage as well the main panel for the house. In a hypothetical world let's say I have a:

    ShopBot CNC machine 110V(60Hz) Single Phase, 20Amp, 4-5HP
    Spindle 110V 20A 1Ø & 220V 90A 1Ø,
    Republic Regenerative Blower - 16.9hpvacuum gauge, 208v, 230v, or 460v; 3 Phase,
    Dust collector 120/240-volt, 60-hertz, single-phase induction motor.

    In order for me to use the machine I might have to have all these items running how do I do that providing I have single phase power. 3 phase power converter? how many items can I run off a power converter? If there are any names of equipment or websites please throw them out I will research.

    Thanks for the insight!!

  2. #2
    Join Date
    Oct 2009
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    Tonasket, WA
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    Quote Originally Posted by Blacknbart View Post

    ShopBot CNC machine 110V(60Hz) Single Phase, 20Amp, 4-5HP Spindle 110V 20A 1Ø & 220V 90A 1Ø,
    That figure is a typo, eh?
    Dust collector 120/240-volt, 60-hertz, single-phase induction motor.
    Needs the amps or HP on that one.
    Also you need to add the load the RPC takes.

    In order for me to use the machine I might have to have all these items running. How do I do that providing I have single phase power. 3 phase power converter? How many items can I run off a power converter?
    Just using a straight calculation, I get roughly 60 Hp at a 200 Amp service.
    Calculations that need to be made drive that number down a ways.
    Wiring run?
    Wire size?
    Voltage selected?
    Start up loads are huge.
    Whether ramped start is used or not used.
    Not all the power available at your service is going to your shop equipment or your house will go dark or vice versa.
    A rule of thumb I think works is...If your 3 Phase power requires 10 HP you need a 20 Hp Phase converter.
    Actually...you will get more bang for your buck and be able to use smaller wire the higher the voltage you select while using 3 phase.

    You can sorta figure how much HP your home is already using by looking at your home electrical bills and kinda sorta see how much you got left.
    Its worth study or a separate dedicated line.
    Last edited by navigator7; 10-17-2010 at 11:18 AM.

  3. #3
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    Custom Interior Products, Lake Worth FL
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    Default

    Chuck, not saying that you are wrong but I run 15hp blower and a 7.5hp radius molder at the same time using a 20 hp rotary converter. Of course they are started at different times but I have had no trouble with this amount of hp. Way back when I was purchasing the converter the people from the company told me that the double the hp thing was associated with digital converters and not rotary.

    Bart, for your calcs.
    My 20 hp converter uses around 20 amps all by it's self with no load on it.

  4. #4
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    Quote Originally Posted by cip View Post
    Chuck, not saying that you are wrong but I run 15hp blower and a 7.5hp radius molder at the same time using a 20 hp rotary converter.
    I understand.
    Some guys would be happy not using the stove, hot water heater, dishwasher and dryer so they have adequate power while they work in their shop.
    Others just want to push the button and things work the way they are supposed to.
    The worse case for you would be a helper pushing the buttons at the same time and tripping a breaker.
    Somebody else might buy a bigger breaker and burn the place down.


    Blacknbart had a typo and insufficient info to give more details.

    I think he should consider a combination of digital convertors and RPC.

    I realized we didn't answer his question. You can run as many machines until you reach the current limit of the breaker.

    It will vary with the distribution of load, hard or soft starts and SNAFUs.

  5. #5
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    Default

    For some practical advice:
    1. I would run all the equipment from a new sub-panel. Your electrician will have to take a look at your current box usage and capacity to determine if you have enough room for what your needs will be but many botters have set up home garage shops with no problem. You will probably also want to run some kind of air-compressor. Home shops can usually do very well on a 5hp 60Gal single phase that usually doesn't require a lot of amps. I had a 40 gal years ago that was 1 1/2HP/110/15. Took a while to fill but worked for quite a while. 20 gal runs out of air too quickly for shop use IMHO
    2. The comments about starting amps/vs running amps and how much really runs at once are the ones that count. So far you have only mentioned 1 3phase piece of equipment and did not give the amps for it.
    3. Shop-bots aren't rated in HP-The spindles are. Your computer and control box are single phase 110 but the control box may need 220 depending on the model and configuration. This document from SB should give you the information you need for your specific needs:
    http://www.shopbottools.com/files/do...haPowerReq.pdf

    I would disagree with their quote of 90 Amps for spindle protection (Not a typo on your part-but straight from their guide above). I do run about everything I need for the bot and a Holzer edgebander off an 80 amp sub and don't use it all. The reason I like a sub-panel is the ability to isolate breakers for computer and control box as well as not crowd my main.

    You should make a clear chart of your needs and err on the side of more rather than less. If you are not specific with your electrician than he won't be able to give you accurate needs or appraisal. Get a couple quotes. Think about making the runs yourself and having the electrician handle hook-ups-big savings there.
    Last edited by bleeth; 10-17-2010 at 11:00 AM.

  6. #6
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    Question Question about Kilowatt Hours?

    I have 125 amp Volt 120/240 A.C. Single Phase control panel. I reviewed my usage back when it was at it's highest which the Kilowatt per Hour was 1093. How do you convert 1093 kWh into a amperage per hour. I've tried different equations, but still not sure if I'm getting the correct answer.

  7. #7
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    Quote Originally Posted by Blacknbart View Post
    I reviewed my usage back when it was at it's highest which the Kilowatt per Hour was 1093. How do you convert 1093 kWh into a amperage per hour. I've tried different equations, but still not sure if I'm getting the correct answer.
    You need a time frame.
    A day?
    A week?
    A Month?

    1093 Kw is 1466 Hp in one hour.

  8. #8
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    Default Oh yeah!

    1093 KWh Average for one Month.

  9. #9
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    Question Power breakdown

    Here's a breakdown list of equipment that might be running at the same time in side my ideal shop.

    Equipment in use Amps
    PRSalpha Shop 30 Single Phase
    Computer/Monitor 2
    HSD 4HP Spindle 33 Single Phase
    Fein shop vac/ holddown 11 only running if needed
    Fein shop vac/ holddown 11 only running if needed
    Fein shop vac dust collection 11
    Air Compressor 15 not always running
    [/B]
    Total 113 Amps

    Amp service 125 amps- 113 amps = 12 Amps available.

    Does this look like a good start? I am missing anything to run the equipment.

    Digital Converter's, RPC's Where do they connect?

    Would a 3 phase converter be helpful to bring down the amperage? Provding I use a 3 phase equipment.

    I will bring up a Sub panel idea with my Electrician buddy.

    In what order does one start up the equipment?

    1.Computer should be running.
    2.Shop Bot
    3.Spindle
    3.hold down Vacs
    4.Dust collection Vacs

    Thanks for the wise & helpful insights guys; I have my father in law coming by on Monday to look things over. I wanted to get my homework done before he gets here.

  10. #10
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    Default

    Quote Originally Posted by Blacknbart View Post
    1093 KWh Average for one Month.
    I get an average of 1.52Kw per hour average.

    You wrote:
    Would a 3 phase converter be helpful to bring down the amperage providing I use a 3 phase equipment?
    I believe the best way to bring down amps is to the increase voltage.
    So ... yes.

    Some motors can be wired to run at more than one voltage.
    Some can run at 120v and 240V.
    Choosing 240v is better.
    Some 3 phase motors can be wired to run at different voltages as well.
    I don't know about the motors you have but I believe 3 phase motors need an extra component called a motor starter to get them going. Without it they just hum and get hot quick.

    I'd start the hardest starting motor first.
    The air compressor may confound you if it decides to start at the same time you start something else, however, not if the system is properly set up.

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