Loading ...
Sorry, an error occurred while loading the content.
 

Re: [mill_drill] Re: Grizzly G1006 Reversing drum switch

Expand Messages
  • philr_77378
    Guenter, There are some solid benefits from this change. Using a Variable Frequency Drive, the input to the VFD can be household 220 single phase, and the VFD
    Message 1 of 17 , Jul 5, 2013
      Guenter,
      There are some solid benefits from this change.
      Using a Variable Frequency Drive, the input to the VFD can be household 220 single phase, and the VFD gives 3 phase power to the motor.  I did this to my South Bend lathe, and can easily control the speed with a knob.  I run the middle belt position, and rarely need to move it.  It works great if you have a long facing cut, you can start outside diameter slower, and use the dial to the RPM up as the tool feeds toward the center of the face off cut.  Another great benefit is the VFD can provide braking to the chuck.  The chuck on my old South Bend stops in a few seconds, which saves work time.
      Phil R



      From: Guenther Paul <paulguenter@...>
      To: "mill_drill@yahoogroups.com" <mill_drill@yahoogroups.com>
      Sent: Friday, July 5, 2013 5:07 AM
      Subject: Re: [mill_drill] Re: Grizzly G1006 Reversing drum switch

       
      I like to ask you for what reson are you converting to 3 phase?  Must have missed your previos threads. I seams single phase would be the way to go for a home shop. All of my machinines are single 110v and 220v that includes a 16"
      south bend lathe
       
      GP
      From: wjhaasman <brianomcp@...>
      To: mill_drill@yahoogroups.com
      Sent: Thursday, July 4, 2013 11:59 PM
      Subject: [mill_drill] Re: Grizzly G1006 Reversing drum switch
       
      Thanks for the help Corey. I added a switch to one of the 240 hot wires and ran the other through the drum switch. now I have forward and reverse. I do plan on switching to a 3 phase motor and converter sometime in the future when I get the extra cash.

      Thanks again,
      Brian



    • Rick Sparber
      GP, I have it on my RF and am spoiled rotten! Rick
      Message 2 of 17 , Jul 5, 2013
        GP,

        I have it on my RF and am spoiled rotten!

        Rick

        On Jul 5, 2013, at 4:33 AM, philr_77378@... wrote:

        Guenter,
        There are some solid benefits from this change.
        Using a Variable Frequency Drive, the input to the VFD can be household 220 single phase, and the VFD gives 3 phase power to the motor.  I did this to my South Bend lathe, and can easily control the speed with a knob.  I run the middle belt position, and rarely need to move it.  It works great if you have a long facing cut, you can start outside diameter slower, and use the dial to the RPM up as the tool feeds toward the center of the face off cut.  Another great benefit is the VFD can provide braking to the chuck.  The chuck on my old South Bend stops in a few seconds, which saves work time.
        Phil R



        From: Guenther Paul <paulguenter@...>
        To: "mill_drill@yahoogroups.com" <mill_drill@yahoogroups.com>
        Sent: Friday, July 5, 2013 5:07 AM
        Subject: Re: [mill_drill] Re: Grizzly G1006 Reversing drum switch

         
        I like to ask you for what reson are you converting to 3 phase?  Must have missed your previos threads. I seams single phase would be the way to go for a home shop. All of my machinines are single 110v and 220v that includes a 16"
        south bend lathe
         
        GP
        From: wjhaasman <brianomcp@...>
        To: mill_drill@yahoogroups.com
        Sent: Thursday, July 4, 2013 11:59 PM
        Subject: [mill_drill] Re: Grizzly G1006 Reversing drum switch
         
        Thanks for the help Corey. I added a switch to one of the 240 hot wires and ran the other through the drum switch. now I have forward and reverse. I do plan on switching to a 3 phase motor and converter sometime in the future when I get the extra cash.

        Thanks again,
        Brian



      • Druid Noibn
        Hi All,   Just a small point to add to the dicussion.   I have and love the VFDs - they work great.  Not all VFDs will work well with 1-phase input, some
        Message 3 of 17 , Jul 5, 2013
          Hi All,
           
          Just a small point to add to the dicussion.
           
          I have and love the VFDs - they work great.  Not all VFDs will work well with 1-phase input, some have to be derated.  Also for small motors, there are VFDs that will work on 120VAC 1-phase and output 220VAC 3-phase. 
           
          If you have a situation where you need to push the motor a bit, the usual approach is to use a larger VFD, e.g., use a 1.5 or 2.0HP VFD for a 1.0 HP motor.  The reason for this is that while most VFDs have overload capability, the % overload and duration may be too little for the application.  Of course, this may not apply to our needs.
           
          My mill/drill runs on 220VAC 1-phase with a VFD.  One of my lathes has a VFD with 120VAC input and soon, I'll hook-up a 120VAC VFD to my other lathe.
           
          Be well,
          DBN

          From: "philr_77378@..." <philr_77378@...>
          To: "mill_drill@yahoogroups.com" <mill_drill@yahoogroups.com>
          Sent: Friday, July 5, 2013 7:33 AM
          Subject: Re: [mill_drill] Re: Grizzly G1006 Reversing drum switch
           
          Guenter,
          There are some solid benefits from this change.
          Using a Variable Frequency Drive, the input to the VFD can be household 220 single phase, and the VFD gives 3 phase power to the motor.  I did this to my South Bend lathe, and can easily control the speed with a knob.  I run the middle belt position, and rarely need to move it.  It works great if you have a long facing cut, you can start outside diameter slower, and use the dial to the RPM up as the tool feeds toward the center of the face off cut.  Another great benefit is the VFD can provide braking to the chuck.  The chuck on my old South Bend stops in a few seconds, which saves work time.
          Phil R


          From: Guenther Paul <paulguenter@...>
          To: "mill_drill@yahoogroups.com" <mill_drill@yahoogroups.com>
          Sent: Friday, July 5, 2013 5:07 AM
          Subject: Re: [mill_drill] Re: Grizzly G1006 Reversing drum switch
           
          I like to ask you for what reson are you converting to 3 phase?  Must have missed your previos threads. I seams single phase would be the way to go for a home shop. All of my machinines are single 110v and 220v that includes a 16"
          south bend lathe
           
          GP
          From: wjhaasman <brianomcp@...>
          To: mill_drill@yahoogroups.com
          Sent: Thursday, July 4, 2013 11:59 PM
          Subject: [mill_drill] Re: Grizzly G1006 Reversing drum switch
           
          Thanks for the help Corey. I added a switch to one of the 240 hot wires and ran the other through the drum switch. now I have forward and reverse. I do plan on switching to a 3 phase motor and converter sometime in the future when I get the extra cash. Thanks again, Brian
        • Rick Sparber
          I should add that my VFD system is powered from single phase 220V and feeds a 3 phase 220V motor that is specifically designed for VFD. I bought the VFD and
          Message 4 of 17 , Jul 5, 2013

            I should add that my VFD system is powered from single phase 220V and feeds a 3 phase 220V motor that is specifically designed for VFD. I bought the VFD and motor as a matched set from the vendor. When I want very slow or very fast spindle speeds, I still must shift belts. But that is very rare.

             

            Rick

             

            From: mill_drill@yahoogroups.com [mailto:mill_drill@yahoogroups.com] On Behalf Of Druid Noibn
            Sent: Friday, July 05, 2013 4:49 AM
            To: mill_drill@yahoogroups.com
            Subject: Re: [mill_drill] Re: Grizzly G1006 Reversing drum switch

             




            Hi All,

             

            Just a small point to add to the dicussion.

             

            I have and love the VFDs - they work great.  Not all VFDs will work well with 1-phase input, some have to be derated.  Also for small motors, there are VFDs that will work on 120VAC 1-phase and output 220VAC 3-phase. 

             

            If you have a situation where you need to push the motor a bit, the usual approach is to use a larger VFD, e.g., use a 1.5 or 2.0HP VFD for a 1.0 HP motor.  The reason for this is that while most VFDs have overload capability, the % overload and duration may be too little for the application.  Of course, this may not apply to our needs.

             

            My mill/drill runs on 220VAC 1-phase with a VFD.  One of my lathes has a VFD with 120VAC input and soon, I'll hook-up a 120VAC VFD to my other lathe.

             

            Be well,

            DBN

             

            From: "philr_77378@..." <philr_77378@...>
            To: "mill_drill@yahoogroups.com" <mill_drill@yahoogroups.com>
            Sent: Friday, July 5, 2013 7:33 AM
            Subject: Re: [mill_drill] Re: Grizzly G1006 Reversing drum switch

             

            Guenter,

            There are some solid benefits from this change.

            Using a Variable Frequency Drive, the input to the VFD can be household 220 single phase, and the VFD gives 3 phase power to the motor.  I did this to my South Bend lathe, and can easily control the speed with a knob.  I run the middle belt position, and rarely need to move it.  It works great if you have a long facing cut, you can start outside diameter slower, and use the dial to the RPM up as the tool feeds toward the center of the face off cut.  Another great benefit is the VFD can provide braking to the chuck.  The chuck on my old South Bend stops in a few seconds, which saves work time.

            Phil R

             

             

            From: Guenther Paul <paulguenter@...>
            To: "mill_drill@yahoogroups.com" <mill_drill@yahoogroups.com>
            Sent: Friday, July 5, 2013 5:07 AM
            Subject: Re: [mill_drill] Re: Grizzly G1006 Reversing drum switch

             

            I like to ask you for what reson are you converting to 3 phase?  Must have missed your previos threads. I seams single phase would be the way to go for a home shop. All of my machinines are single 110v and 220v that includes a 16"

            south bend lathe

             

            GP

            From: wjhaasman <brianomcp@...>
            To: mill_drill@yahoogroups.com
            Sent: Thursday, July 4, 2013 11:59 PM
            Subject: [mill_drill] Re: Grizzly G1006 Reversing drum switch

             

            Thanks for the help Corey. I added a switch to one of the 240 hot wires and ran the other through the drum switch. now I have forward and reverse. I do plan on switching to a 3 phase motor and converter sometime in the future when I get the extra cash. Thanks again, Brian




          • wjhaasman
            What I meant was; Get a 3 phase motor with a phase converter to run on 240V household current then add a VFD for speed control. Cash permitting that is.
            Message 5 of 17 , Jul 5, 2013
              What I meant was; Get a 3 phase motor with a phase converter to run on 240V household current then add a VFD for speed control. Cash permitting that is.
            • Ramdog
              With a VFD you don t need a Phase Converter. The VFD takes the place of it, and gives you variable speed.
              Message 6 of 17 , Jul 5, 2013
                With a VFD you don't need a Phase Converter. The VFD takes the place of it, and gives you variable speed.

                --- In mill_drill@yahoogroups.com, "wjhaasman" <brianomcp@...> wrote:
                >
                > What I meant was; Get a 3 phase motor with a phase converter to run on 240V household current then add a VFD for speed control. Cash permitting that is.
                >
              • Guenther Paul
                Did you all ever figure the operating cost i mean the cosumtion of elec. to convert single to 3 phase. GP ________________________________ From: wjhaasman
                Message 7 of 17 , Jul 5, 2013
                  Did you all ever figure the operating cost i mean the cosumtion of elec. to convert single to 3 phase.
                   
                  GP
                  From: wjhaasman <brianomcp@...>
                  To: mill_drill@yahoogroups.com
                  Sent: Friday, July 5, 2013 11:26 AM
                  Subject: [mill_drill] Re: Grizzly G1006 Reversing drum switch
                   
                  What I meant was; Get a 3 phase motor with a phase converter to run on 240V household current then add a VFD for speed control. Cash permitting that is.

                • Rick Sparber
                  GP, My single phase 220V to 3 phase 220V VFD runs cool to the touch which means that the energy consumed in the conversion is tiny. Besides, most of my time is
                  Message 8 of 17 , Jul 5, 2013

                    GP,

                     

                    My single phase 220V to 3 phase 220V VFD runs cool to the touch which means that the energy consumed in the conversion is tiny. Besides, most of my time is spent on set up, not running the mill.

                     

                    Rick

                     

                    From: mill_drill@yahoogroups.com [mailto:mill_drill@yahoogroups.com] On Behalf Of Guenther Paul
                    Sent: Friday, July 05, 2013 8:44 AM
                    To: mill_drill@yahoogroups.com
                    Subject: Re: [mill_drill] Re: Grizzly G1006 Reversing drum switch

                     




                    Did you all ever figure the operating cost i mean the cosumtion of elec. to convert single to 3 phase.

                     

                    GP

                    From: wjhaasman <brianomcp@...>
                    To: mill_drill@yahoogroups.com
                    Sent: Friday, July 5, 2013 11:26 AM
                    Subject: [mill_drill] Re: Grizzly G1006 Reversing drum switch

                     

                    What I meant was; Get a 3 phase motor with a phase converter to run on 240V household current then add a VFD for speed control. Cash permitting that is.




                  • Corey Renner
                    Rotary phase converters waste a little bit of power, vfd s are very efficient. I read somewhere that a bridgeport working an 8hr shift taking heavy cuts uses
                    Message 9 of 17 , Jul 5, 2013

                      Rotary phase converters waste a little bit of power, vfd's are very efficient.  I read somewhere that a bridgeport working an 8hr shift taking heavy cuts uses something like 35cents worth of electricity per day. Even if it's doubled or tripled since then, its negligible.

                      Cheers, c

                      On Jul 5, 2013 8:46 AM, "Guenther Paul" <paulguenter@...> wrote:
                       

                      Did you all ever figure the operating cost i mean the cosumtion of elec. to convert single to 3 phase.
                       
                      GP
                      From: wjhaasman <brianomcp@...>
                      To: mill_drill@yahoogroups.com
                      Sent: Friday, July 5, 2013 11:26 AM
                      Subject: [mill_drill] Re: Grizzly G1006 Reversing drum switch
                       
                      What I meant was; Get a 3 phase motor with a phase converter to run on 240V household current then add a VFD for speed control. Cash permitting that is.

                    • Druid Noibn
                      Hi GP,   Interesting question, one that an engineer is likely to ask   We see lots of comments on this point, all good of course, but s let s stick
                      Message 10 of 17 , Jul 6, 2013
                        Hi GP,
                         
                        Interesting question, one that an engineer is likely to ask <smile>
                         
                        We see lots of comments on this point, all good of course, but's let's stick with our engineering. 
                         
                        First - let's consider the approach to get 3-phase power 1) ask the power company to run a 3-phase line to our facilities and a licensed electrician to install the wiring (FYI, in NJ two folks can do the internal wiring on a home - the home owner or a licensed electrician); 2) get a rotary converter; 3) get a static converter; 4) get a VFD.  The last few points "assumes" that one has the appropriate power wired into the shop. 
                         
                        Item 1 is very good - and can be rather expensive as it depends a lot on what is available in your area.  I would have to pay, to have a power line brought in from a couple of blocks away.  Considering potential use - the utility company would not be eager to do it and it would be expensive. 
                         
                        Item 2- rotary converters are motor/generators (motoralternators if you wish) - they are very nice and lets one get full 3-pahse power.  Bigger is not always better and some control might be in order - not likley an issue for our needs and they are very reliable.  Probably best to find a good used one, as they can be expensive.
                         
                        Item 3 - static converters - they are sized to a particular motor size, and supply about 66% of the rated power - use only if forced to.  Look up as to what they really are <smile> - make your own.
                         
                        Item  4 - VFD - these are adjustable electronically controled converters - takes in AC converts it to DC and converts that back to AC; and are very efficient at doing so.  I'll leave it up to others to look up the specs on a few noting their total power consumption and conversion - they are efficient.  The output is variable, i.e., you can adjust the output such that it will allow the "motor" to vary it speed over a wide range.  It is not generally recommented to run multiple motors concurrently, although it can be done.  DO NOT put a switch, circuit breaket, relay, contactor or other disconnect device between the motor and the VFD.  For those areas when the safety rule demands a disconnect here - read the manual - some system permit a disconnect X milleseconds after interrupting the main power input. Cost...? varies with size of VFD and manufacturer - consider $130-$450 for the ones we typically need 
                         
                        Now, what the heck does the above have to do with the question? <smile>  
                         
                        The cost of 3-phase power depends on the approach used and it isn't only the $/KWH but also the cost of equipment needed. 
                         
                        Why did a fellow like me switch to a 3-phase system when I certainly know that it would not improve my work?  Because, I wanted to - it is a part of the fun I get working in my shop; and it is a part of my learning.  Heck, look at the speed adjustments on typical system, we may have "Low, Medium and High" yet we go a bit crazy discussing SFM (surface feet per minute) cutting speeds; an issue better left for those in production manufacturing. 
                         
                        I hope the above was of some interest.
                         
                        Kind regards,
                        DBN  

                        From: Guenther Paul <paulguenter@...>
                        To: "mill_drill@yahoogroups.com" <mill_drill@yahoogroups.com>
                        Sent: Friday, July 5, 2013 11:44 AM
                        Subject: Re: [mill_drill] Re: Grizzly G1006 Reversing drum switch
                         
                        Did you all ever figure the operating cost i mean the cosumtion of elec. to convert single to 3 phase.
                         
                        GP
                        From: wjhaasman <brianomcp@...>
                        To: mill_drill@yahoogroups.com
                        Sent: Friday, July 5, 2013 11:26 AM
                        Subject: [mill_drill] Re: Grizzly G1006 Reversing drum switch
                         
                        What I meant was; Get a 3 phase motor with a phase converter to run on 240V household current then add a VFD for speed control. Cash permitting that is.
                      • Guenther Paul
                        Druid I have 3phase on the pole across the street, The power company will not hook up 3-phase to my property i am zoned agricultural-residential  i would
                        Message 11 of 17 , Jul 6, 2013
                          Druid
                          I have 3phase on the pole across the street, The power company will not hook up 3-phase to my property i am zoned
                          agricultural-residential  i would need at least a light commercial zoning. Acutely i am fine all my machines i have now run a single phase but that may change ho knows i may get a machine with a 3phase
                           
                          GP
                           motor
                          From: Druid Noibn <druid_noibn@...>
                          To: "mill_drill@yahoogroups.com" <mill_drill@yahoogroups.com>
                          Sent: Saturday, July 6, 2013 4:48 PM
                          Subject: Re: [mill_drill] Re: Grizzly G1006 Reversing drum switch
                           
                          Hi GP,
                           
                          Interesting question, one that an engineer is likely to ask <smile>
                           
                          We see lots of comments on this point, all good of course, but's let's stick with our engineering. 
                           
                          First - let's consider the approach to get 3-phase power 1) ask the power company to run a 3-phase line to our facilities and a licensed electrician to install the wiring (FYI, in NJ two folks can do the internal wiring on a home - the home owner or a licensed electrician); 2) get a rotary converter; 3) get a static converter; 4) get a VFD.  The last few points "assumes" that one has the appropriate power wired into the shop. 
                           
                          Item 1 is very good - and can be rather expensive as it depends a lot on what is available in your area.  I would have to pay, to have a power line brought in from a couple of blocks away.  Considering potential use - the utility company would not be eager to do it and it would be expensive. 
                           
                          Item 2- rotary converters are motor/generators (motoralternators if you wish) - they are very nice and lets one get full 3-pahse power.  Bigger is not always better and some control might be in order - not likley an issue for our needs and they are very reliable.  Probably best to find a good used one, as they can be expensive.
                           
                          Item 3 - static converters - they are sized to a particular motor size, and supply about 66% of the rated power - use only if forced to.  Look up as to what they really are <smile> - make your own.
                           
                          Item  4 - VFD - these are adjustable electronically controled converters - takes in AC converts it to DC and converts that back to AC; and are very efficient at doing so.  I'll leave it up to others to look up the specs on a few noting their total power consumption and conversion - they are efficient.  The output is variable, i.e., you can adjust the output such that it will allow the "motor" to vary it speed over a wide range.  It is not generally recommented to run multiple motors concurrently, although it can be done.  DO NOT put a switch, circuit breaket, relay, contactor or other disconnect device between the motor and the VFD.  For those areas when the safety rule demands a disconnect here - read the manual - some system permit a disconnect X milleseconds after interrupting the main power input. Cost...? varies with size of VFD and manufacturer - consider $130-$450 for the ones we typically need 
                           
                          Now, what the heck does the above have to do with the question? <smile>  
                           
                          The cost of 3-phase power depends on the approach used and it isn't only the $/KWH but also the cost of equipment needed. 
                           
                          Why did a fellow like me switch to a 3-phase system when I certainly know that it would not improve my work?  Because, I wanted to - it is a part of the fun I get working in my shop; and it is a part of my learning.  Heck, look at the speed adjustments on typical system, we may have "Low, Medium and High" yet we go a bit crazy discussing SFM (surface feet per minute) cutting speeds; an issue better left for those in production manufacturing. 
                           
                          I hope the above was of some interest.
                           
                          Kind regards,
                          DBN  

                          From: Guenther Paul <paulguenter@...>
                          To: "mill_drill@yahoogroups.com" <mill_drill@yahoogroups.com>
                          Sent: Friday, July 5, 2013 11:44 AM
                          Subject: Re: [mill_drill] Re: Grizzly G1006 Reversing drum switch
                           
                          Did you all ever figure the operating cost i mean the cosumtion of elec. to convert single to 3 phase.
                           
                          GP
                          From: wjhaasman <brianomcp@...>
                          To: mill_drill@yahoogroups.com
                          Sent: Friday, July 5, 2013 11:26 AM
                          Subject: [mill_drill] Re: Grizzly G1006 Reversing drum switch
                           
                          What I meant was; Get a 3 phase motor with a phase converter to run on 240V household current then add a VFD for speed control. Cash permitting that is.
                           
                        • Druid Noibn
                          Hi GP,   Yes, indeed... The utility companies can be rather difficult at times and it is very difficult to get the folks to change their minds.    If one
                          Message 12 of 17 , Jul 7, 2013
                            Hi GP,
                             
                            Yes, indeed... The utility companies can be rather difficult at times and it is very difficult to get the folks to change their minds. 
                             
                            If one really wants the utility company to consider bringing the power over (the cost can be a surprise - depending on teh factors involved) one might ask the town board for a variance on the property.  For a residential area, the chance is very low.  Sometimes one might see some success IF...you can demonstrate that there would be no increase in traffic, no trucks (other than the usual USPS, UPS, FedEx and rare other delieveries...) and no increase in pedestrian trafic, e.g., not open to the public.  
                             
                            It's easier to get a converter <smile>  The VFDs that I have all worked well, so far. 
                             
                            Be well,
                            DBN

                            From: Guenther Paul <paulguenter@...>
                            To: "mill_drill@yahoogroups.com" <mill_drill@yahoogroups.com>
                            Sent: Saturday, July 6, 2013 5:06 PM
                            Subject: Re: [mill_drill] Re: Grizzly G1006 Reversing drum switch
                             
                            Druid
                            I have 3phase on the pole across the street, The power company will not hook up 3-phase to my property i am zoned
                            agricultural-residential  i would need at least a light commercial zoning. Acutely i am fine all my machines i have now run a single phase but that may change ho knows i may get a machine with a 3phase
                             
                            GP
                             motor
                            From: Druid Noibn <druid_noibn@...>
                            To: "mill_drill@yahoogroups.com" <mill_drill@yahoogroups.com>
                            Sent: Saturday, July 6, 2013 4:48 PM
                            Subject: Re: [mill_drill] Re: Grizzly G1006 Reversing drum switch
                             
                            Hi GP,
                             
                            Interesting question, one that an engineer is likely to ask <smile>
                             
                            We see lots of comments on this point, all good of course, but's let's stick with our engineering. 
                             
                            First - let's consider the approach to get 3-phase power 1) ask the power company to run a 3-phase line to our facilities and a licensed electrician to install the wiring (FYI, in NJ two folks can do the internal wiring on a home - the home owner or a licensed electrician); 2) get a rotary converter; 3) get a static converter; 4) get a VFD.  The last few points "assumes" that one has the appropriate power wired into the shop. 
                             
                            Item 1 is very good - and can be rather expensive as it depends a lot on what is available in your area.  I would have to pay, to have a power line brought in from a couple of blocks away.  Considering potential use - the utility company would not be eager to do it and it would be expensive. 
                             
                            Item 2- rotary converters are motor/generators (motoralternators if you wish) - they are very nice and lets one get full 3-pahse power.  Bigger is not always better and some control might be in order - not likley an issue for our needs and they are very reliable.  Probably best to find a good used one, as they can be expensive.
                             
                            Item 3 - static converters - they are sized to a particular motor size, and supply about 66% of the rated power - use only if forced to.  Look up as to what they really are <smile> - make your own.
                             
                            Item  4 - VFD - these are adjustable electronically controled converters - takes in AC converts it to DC and converts that back to AC; and are very efficient at doing so.  I'll leave it up to others to look up the specs on a few noting their total power consumption and conversion - they are efficient.  The output is variable, i.e., you can adjust the output such that it will allow the "motor" to vary it speed over a wide range.  It is not generally recommented to run multiple motors concurrently, although it can be done.  DO NOT put a switch, circuit breaket, relay, contactor or other disconnect device between the motor and the VFD.  For those areas when the safety rule demands a disconnect here - read the manual - some system permit a disconnect X milleseconds after interrupting the main power input. Cost...? varies with size of VFD and manufacturer - consider $130-$450 for the ones we typically need 
                             
                            Now, what the heck does the above have to do with the question? <smile>  
                             
                            The cost of 3-phase power depends on the approach used and it isn't only the $/KWH but also the cost of equipment needed. 
                             
                            Why did a fellow like me switch to a 3-phase system when I certainly know that it would not improve my work?  Because, I wanted to - it is a part of the fun I get working in my shop; and it is a part of my learning.  Heck, look at the speed adjustments on typical system, we may have "Low, Medium and High" yet we go a bit crazy discussing SFM (surface feet per minute) cutting speeds; an issue better left for those in production manufacturing. 
                             
                            I hope the above was of some interest.
                             
                            Kind regards,
                            DBN  

                            From: Guenther Paul <paulguenter@...>
                            To: "mill_drill@yahoogroups.com" <mill_drill@yahoogroups.com>
                            Sent: Friday, July 5, 2013 11:44 AM
                            Subject: Re: [mill_drill] Re: Grizzly G1006 Reversing drum switch
                             
                            Did you all ever figure the operating cost i mean the cosumtion of elec. to convert single to 3 phase.
                             
                            GP
                            From: wjhaasman <brianomcp@...>
                            To: mill_drill@yahoogroups.com
                            Sent: Friday, July 5, 2013 11:26 AM
                            Subject: [mill_drill] Re: Grizzly G1006 Reversing drum switch
                             
                            What I meant was; Get a 3 phase motor with a phase converter to run on 240V household current then add a VFD for speed control. Cash permitting that is.
                             
                          Your message has been successfully submitted and would be delivered to recipients shortly.