Phase converter help

[TommyD]

I have an old Delta Rockwell 7" pedestal grinder, lighted eye shields, AB on/off switch and a coolant cup, a real workhorse. I want to use it in my shop BUT it's 3 phase.

Anyone make their own phase converter? I've done some searching on the internet but I'm just not sure I completely understand some of what they are writing.

Anyone buy a converter? Price? I've inquired a couple of sites that supply them, asking what I would need, etc. but not a one has answered my request.

Should I just try and sell it on Craigs List? I saw a thread here about one a guy was considering on buying but it was on as bench, I saw someone write that if it were on a pedestal it would be worth about $200....would this be a decent asking price or would the 3 phase make it hard to get rid of?

I bought a Harbor Freight 6" in the mean time and I'm NOT impressed, push a little too hard and it bogs down.

I'm looking for ideas right now, money is tight so if a phase converter is too much to buy or construct...I'll probably sell it.

Thanks in advance...

 

[GaryRoushkolb]

Phase-o-matic, got one on my mill and it works great.

 

[TommyD]

Phase-o-matic, got one on my mill and it works great.

What did you pay for it??

 

[larry_g]

http://www.metalwebnews.com/howto/ph-conv/ph-conv.html

I followed the plans in the above link and have been running the converter for better than 10 years. Scrounging parts I came in at under $100. I do know a bit about electricity and electronics though and modified the control circuit to run 24vdc as that is what I had for relays.

I have a really hard time wasting time on such a dumb looking guy in the avatar. I tend to judge people by their avatar.

lg
no neat sig line

 

[930dreamer]

How many HP? A vfd could be an option.

http://www.automationdirect.com/adc...edium=cpc&utm_term=vfd&utm_campaign=ac+drives

 

[Mmfh]

They are easy to build, get a 3 phase motor the same size as the one on the grinder, get a 1/2 hp or so single phase motor that is 120 v, put a belt between the two so if one spins the other spins.
Put power to the smaller motor with a wall switch, it spins because you just gave it power, the three phase motor spins because its hooked by a belt. Turn off the power to the small motor at the same time as giving 220v single phase to the larger three phase motor.

The three phase motor will keep running on the 220v single phase power you are giving it. It only needs the 3 phase power to start. Use the small motor to start the larger one. 3 phase motor has 3 leads coming out of it, two of them you have the 220v going too, the last one is powered from the magnetic field generating from the two you are giving power too. Now you have three live wires, 3 phase.

Hook up to your grinder, grind away.

That is the simplest way to make your own three phase power, I've been doing it with a 25 hp for longer than I can remember.

If you have questions read Larrys link above,

Mm

 

[TommyD]

http://www.metalwebnews.com/howto/ph-conv/ph-conv.html

I followed the plans in the above link and have been running the converter for better than 10 years. Scrounging parts I came in at under $100. I do know a bit about electricity and electronics though and modified the control circuit to run 24vdc as that is what I had for relays.

I have a really hard time wasting time on such a dumb looking guy in the avatar. I tend to judge people by their avatar.

lg
no neat sig line

Don't bother to read my posts or threads if you are that simple minded. I don't like narrow minded people named larry who spell their name with a lower case L...I can't waste my time on them...duh!

You, madam, are a real beauty...how ya like me now???

 

[TommyD]

Thanks for the ideas...even you larry. Yeesh!

 

[Norcal]

I bought a Rockwell 7" grinder from a school that is 200V 3Ø, my plan is to use a 1/2 HP drive (VFD) to power it as most newer models allow the output voltage to be set by the user, factory default voltage is 230V, setting it for 208V is simple.

It is a 70's model that has the cast iron base & sheet metal pedestal* w/ the LVC (Low Voltage Control) option mounted in the pedestal, my plan is to strip out the original overload relay & use the existing DP contactor to power a control transformer for the lights in the eye shields & the VFD, now just make the time to do it......

*Older ones were all cast iron & are quite desirable.

 

[TommyD]

Mine is slightly different than yours....but not much. Just from memory the column is cast (it's out in my gay-raj and it's raining now). I had my electrician look at it and he basically told me to either sell it or get phase converter.

I don't want to hack it up too badly, how you going about using the VFD? Electricity isn't my bag, tool and die I'm a whiz at.

How much did you pay for yours? Thanks for the reply.

 

[Norcal]

I think I paid $150 plus "Moonbeam" (sales) tax for the grinder, the VFD is a 1/2 HP GE/Fuji 240V drive that was around $80, but VFD's 1 HP & under are avail w/ 120 volt input which IMO is the best choice for smaller motors as 120 volts is everywhere but 240 is not, you do not want to switch the output of the VFD, they don't like it when running, perhaps I will get off my azz & get mine going......

 

[TommyD]

We had a number of the cast columns, some were set up for side wheeling carbide cutting tools with a green wheel on one side and a diamond wheel on the other side, with a drip cup for coolant. The tool rest table the width of the grinder and slotted for use with a miter gage for compound anglee grinds. All the machine tools were pre-60's vintage and all were cast iron. Gawd, I miss that shop...

Thanks for the info, much appreciated. Now get off yer azz and git-er-dun....

 

[klhitman]

whats the voltage and HP. a VFD might be the way to go. i have looked into this and there are plenty of company's out that make phase converters or a add a phase. they cost a lot. addaphase.com is one of them. a VFD of EBAY could be you solution. i can get you a VFD but i am not as cheap as i thought i was. 3 phase is hard to come by so its kind of a hard sell, as the home user doesn't have it as where a company would.

 

[clark_nicholas]

They are easy to build, get a 3 phase motor the same size as the one on the grinder, get a 1/2 hp or so single phase motor that is 120 v, put a belt between the two so if one spins the other spins.
Put power to the smaller motor with a wall switch, it spins because you just gave it power, the three phase motor spins because its hooked by a belt. Turn off the power to the small motor at the same time as giving 220v single phase to the larger three phase motor.

The three phase motor will keep running on the 220v single phase power you are giving it. It only needs the 3 phase power to start. Use the small motor to start the larger one. 3 phase motor has 3 leads coming out of it, two of them you have the 220v going too, the last one is powered from the magnetic field generating from the two you are giving power too. Now you have three live wires, 3 phase.

Hook up to your grinder, grind away.

That is the simplest way to make your own three phase power, I've been doing it with a 25 hp for longer than I can remember.

If you have questions read Larrys link above,

Mm

Have you done this before because im pretty sure you still going to single phase that motor and burn it up

 

[930dreamer]

They are easy to build, get a 3 phase motor the same size as the one on the grinder, get a 1/2 hp or so single phase motor that is 120 v, put a belt between the two so if one spins the other spins.
Put power to the smaller motor with a wall switch, it spins because you just gave it power, the three phase motor spins because its hooked by a belt. Turn off the power to the small motor at the same time as giving 220v single phase to the larger three phase motor.

The three phase motor will keep running on the 220v single phase power you are giving it. It only needs the 3 phase power to start. Use the small motor to start the larger one. 3 phase motor has 3 leads coming out of it, two of them you have the 220v going too, the last one is powered from the magnetic field generating from the two you are giving power too. Now you have three live wires, 3 phase.

Hook up to your grinder, grind away.

That is the simplest way to make your own three phase power, I've been doing it with a 25 hp for longer than I can remember.

If you have questions read Larrys link above,

Mm

I've built three this way, works perfect.

 

[Mmfh]

As 930 dreamer said, do it all the time. And have for a lot of years!

 

[Rogue1987]

This place (Garage Journal) is horrible. Now I need to go buy something 3 phase so I can build a converter...

 

[clark_nicholas]

How do you have over current protection do install some fuse block or motor starter

 

[Norcal]

I finally mounted & wired the VFD & control transformer in the grinder pedestal, after getting some error codes & changing a parameter to make it go away, it runs.

The drive is a GE/Fuji 1/2 HP, 230V, 1Ø input model, the control transformer is for the lighted eyeshields, I was not going to use a 4-wire cord & attachment plug, so a transformer was the only way to get 120 volts for the lights, the existing contactor & control transformer was retained, but the overload relay was removed (all 3 were part of the OEM Rockwell LVC,24V control option), the contactor supplies power to the drive, & control transformer, & the orig. toggle switch for the lights starts the grinder, motor is 200V 3Ø & the VFD's output voltage has been adjusted to 208V.

 

[duude]

I made a simple one.

 

[brucer]

You dont lose power with a vfd like you do with a static phase converter.. I'm running a GE vat20 vfd on my 1972 bridgeport mill, it works great..

 

[Mmfh]

You dont lose power with a vfd like you do with a static phase converter.. I'm running a GE vat20 vfd on my 1972 bridgeport mill, it works great..

A '72 BP, is that one of those round ram BP?
Do you use the VFD for speed control? I've wondered if you put the belts to the high speed position, and then run the speed through the VFD? Been wanting to try that but have found the VFD's are kinda pricey.

Where did you buy yours?

 

[Norcal]

A '72 BP, is that one of those round ram BP?
Do you use the VFD for speed control? I've wondered if you put the belts to the high speed position, and then run the speed through the VFD? Been wanting to try that but have found the VFD's are kinda pricey.

Where did you buy yours?

A 3 HP & smaller VFD is not expensive, over the 3 HP threshold, they start getting pricey though....

A 3 HP 1Ø input GE / Fuji for a Rockwell shaper was less then $200 shipped.

 

[larry_g]

I've wondered if you put the belts to the high speed position, and then run the speed through the VFD?

Where did you buy yours?

One of the things about a VFD is that they will run all sorts of speeds you will want to run your motor near rated speed. So you still have some belt changing to do. Run to slow under load and the cooling fan will not be effective, to fast and risk throwing a winding. I've used -40 +20% rated speed for a rule of thumb. You program in the min and max speed you want to run and then you can select any speed within that range. Kinda like a rev limiter on a motor when you hit the limiter you shift gears.

lg
no neat sig line

 

[Jim Johnstone]

Ok, another question from a guy looking to build a RPC. I have a 15hp 3ph motor just sitting in my garage. If I build a phase converter using it, is it recommended to have that one phase converter dedicated to one machine, or could I theoretically run 3 separate 5hp machines at the same time?

 

[Mmfh]

Ok, another question from a guy looking to build a RPC. I have a 15hp 3ph motor just sitting in my garage. If I build a phase converter using it, is it recommended to have that one phase converter dedicated to one machine, or could I theoretically run 3 separate 5hp machines at the same time?

I have a 25hp converter that I put together. I use it for several machines, I can run them all at the same time if I want too. Actually the more 3 phase machines you have running the better.

Mine is not fancy, just my big 25hp being belt driven by a 1 1/2hp single phase 120v motor. Once the small motor brings the big one up to speed with the belt between them. I shut the power down to the small one and turn power on to the big one. The big one will give me the three phase I need to start whatever else I want to run.

It really can be that simple.

Mm

 

[larry_g]

Ok, another question from a guy looking to build a RPC. I have a 15hp 3ph motor just sitting in my garage. If I build a phase converter using it, is it recommended to have that one phase converter dedicated to one machine, or could I theoretically run 3 separate 5hp machines at the same time?

Follow the link I posted in post 4 above. Lots of information. If you get that 15hp set up then you can run more than 3x5hp. As mmfh said aditional motors act to generate a better system so you could run 3x15hp IF you had the single phase circuit powering the converter sized to run 45 hp. At these power levels your going to have to know what your doing.

lg
no neat sig line