5 Hp 3 Phase

[drill]

I would like some guidance on the wiring of my mill. I have a 1984 hurco KMB1 bx w/o tool changer. My question is the only thing that is 3 phase is the 5 hp spindle motor, I'm sure that is all that is 3 phase this machine also has a parajust (not sure what that is) but would it be a good choice to get a 5hp 3 phase converter since the only thing that needs it is the spindle motor. On more thing I do not want a vfd.

[NC Cams]

I"m not an expert on 3 phase Hurco's, BUT I do have some experience with connecting single phase equipment to a 3 phase lathe (IE: PC for tape reader replacement).

In a simple sentence, if it was designed to run on a common source 3 phase, buy a suitably sized phase converter and run it that way. YOu can create some real headaches trying to interface 3phase to single thru a phase converter if you're not careful.

I suspect someone will advise otherwise but we had troubles mixing single and 3 phase equipment due to ground loop current issues. Got real co$tly.

[Al_The_Man]

If you decide to build a rotary converter there are a few links here if you do a search, I built my own sucessfully.
Make sure however that you put the single phase fed control on the main two-wire 240, not the artificial leg.
I assume it is set up for 220~240 three phase.
Al.

[Servo Wizard]

drill,

It's highly unlikely that the machine would be single phase. Rotary phase converters are an obsolete method for generating three phase power. Most variable frequency drives (VFD) will operate on single phase current and produce three phase current, however there's 33% reduction in output so a 5HP application would require a 7.5HP VFD. Variable frequency drives convert AC current to DC current and then redistribute it as three phase frequency modulated AC current.

Servo

[Al_The_Man]

Originally Posted by Servo Wizard drill, Rotary phase converters are an obsolete method for generating three phase power.

I would not say it obsolete for the hobyist, You can build your own for ~$200.00 against $2K for a decent 7.5HP VFD. Also if you happen to pick up other three phase motorized equipment, the Rotary converter can be used to feed up to double its HP rating due to other motors acting to assist the converter, as long as the largest motor is no larger than the converter.
Al.

[gtd107]

I have to disagree with Servo Wizard and All_the_man. I have had great success with the Hitachi VFD's I have purchased and would recommend them to anybody that wants an affordable solution to 3phase. You can't beat the variable speed controls and the braking (great for tapping). Check out this months "The Home Shop Machinist" mag. It has a great article in the back. Also, if you have a 5hp motor, you buy a 5hp VFD. the 33% reduction is for static phase controllers, not VFD's. I bought one of my VFD's fro my Index Mill on driveswarehouse.com and they were helpful. When you look at the prices you will find them very good. The only negitive about a VFD is that you cannot run multiple machines on one VFD. That is where a Rotary Converter is nice.

[Al_The_Man]

Originally Posted by gtd107 I have to disagree with Servo Wizard and All_the_man. I have had great success with the Hitachi VFD's I have purchased and would recommend them to anybody that wants an affordable solution to 3phase. You can't beat the variable speed controls and the braking (great for tapping). Check out this months "The Home Shop Machinist" mag. It has a great article in the back. Also, if you have a 5hp motor, you buy a 5hp VFD. the 33% reduction is for static phase controllers, not VFD's. I bought one of my VFD's fro my Index Mill on driveswarehouse.com and they were helpful. When you look at the prices you will find them very good. The only negitive about a VFD is that you cannot run multiple machines on one VFD. That is where a Rotary Converter is nice.

No1, I was not knocking VFD's as I have used them extensively, the poster specifically said he did not want a VFD.
Also the derating DOES apply to VFD of some makes when using them on single phase, You have to check with the individual manufacturers recomendations, also there is a practical size limit when using single phase.
Also, many people buy the economy version of VFD which is not Flux Vector control, If you want nice spindle control, this is the only way to go, but cost more.
Al.

[gtd107]

Sorry, Missed the part about not wanting the VFD. I will bow out I just love the VFD's though, I will never go back to a rotary or static. I love to be able to program and control the machine.

[Servo Wizard]

Al_The_Man,

I cannot believe that you would think that I was recommending a solution that would cost $2K. I purchase new Yaskawa and Mitsubishi VFDs through eBay auctions and I have not paid over $500.00 for any one of them.

gtd107,

Why do say that you disagree with Servo? Sounds to me like you are an advocate for using variable frequency drives for the purpose of generating three phase current which is exactly what I recommended.

Servo

[gtd107]

Servo,

I just disagreed with the 33% power loss on and manification of the VFD needed. Everything I have read to date on modern VFD's for HP under 10 states that Power is not reduced. Both my VFD's, one is a 3hp and the other is 1/2 hp, have full rated power and work excellent... I have actully been told by a friend that rebuilds glass bottle machines, that I should not over rate the VFD's. Although in the settings you can adjust for the exact motor you have. I just feel that VFD's are the way to go because of the programming you are able to do. I was amazed at how easy it was to set up and operate. Anybody that messes around with CNC programing would be more than able to program one.

[jmelson]

Why are you sure you don't want a VFD? Do you have 3-phase power there? As for power loss,
that is totally wrong. Most VFDs have a "torque boost" mode that allows the motor to
provide MORE than rated torque for a few seconds at a time. Also, hard-starting a 5 HP motor
on residential service will definitely cause every light in your house to blink, rotary converter
or not. The VFD has a soft-start that eliminates this. Also, you get very effective braking for
free, as well as electronic reversing and variable speed. How could this ever be wrong?

The only thing that will give a 33% power loss is a "static" converter, which is really a starting capacitor and a relay, in a $150 box. (Ie, a big ripoff.)

Jon

[drill]

OK, OK what type of VFD do I get and can anyone show a pic or drawing of the wiring process. and will I be able to get one for less then $475.00
and if so where might that be. also the spindle rpm is already programable
thru g and m code and also conv.. also that the only thing that is 3 phase is the spindle motor and the rest runs thru a parajust wich I was told was already a VFD in many ways and that is what "seperates" the power from 3 phase to single.