VFD Needed

Thanks Jon! I guess that sort of keeps the RPC around! and lowers the needs on the VFD. I don't even know what CNC I will wind up with but I'm sure it's not going to be a real big one. A home shop size used cheap-o is most likely to find itself at my place.. This is why I ask my questions here!!!!

Thanks a million!

Rob

Rob....you can run individual machines with VFDs, or even several, running one at a time, but you wont be able to run a CNC anything off a VFD. If there is a VFD incorporated in the CNC machine..fine. But dont try to run a VFD from a VFD...bad things happen then the magic smoke comes out.

Same with DC drives on OD grinders that use one leg for the live spindle....blush...

A RPC has a definate place in the shop. A VFD is an individual replacement for them, but not a mass replacement. You can run multiple machines at the same time, turning various ones off and on while others are running. Doing the same with a VFD may well let out the magic smoke.

A VFD on a step pully Bridgeport is a marvelous thing. Makes it even more versitile than a varible speed Bridgeport.

On the other hand...I have a Larios horizontal mill. Nice 40 taper machine. 3hp on the spindle, 2 hp on the power feed(s) and a 3ph coolant pump.

Where do I put the VFD?

As I said....RPCs have a definate place.

Gunner

"[L]iberals are afraid to state what they truly believe in, for to do so would result in even less votes than they currently receive. Their methodology is to lie about their real agenda in the hopes of regaining power, at which point they will do whatever they damn well please. The problem is they have concealed and obfuscated for so long that, as a group, they themselves are no longer sure of their goals. They are a collection of wild-eyed splinter groups, all holding a grab-bag of dreams and wishes. Some want a Socialist, secular-humanist state, others the repeal of the Second Amendment. Some want same sex/different species marriage, others want voting rights for trees, fish, coal and bugs. Some want cradle to grave care and complete subservience to the government nanny state, others want a culture that walks in lockstep and speaks only with intonations of political correctness. I view the American liberals in much the same way I view the competing factions of Islamic fundamentalists. The latter hate each other to the core, and only join forces to attack the US or Israel. The former hate themselves to the core, and only join forces to attack George Bush and conservatives." --Ron Marr

I would speculate that you could do a little electronic work on a smaller CNC and make it happy with single phase power - would take looking at the specific unit though.

Your motor is 1 HP, right? I have a lot of drives right now and will be happy to set you up with one. I will give you a price much better than I get for them on eBay. (like 40% off)

Running CNC machines on drives depends on what machine, some need real

Gunner, You make some good points I had never considered.

Ivan Vegvary

Rob...I think most folks would be well served with a 5hp RPC at the biggest.

I was impressed by one a friend purchased off Ebay a few years ago. The seller was putting them in nice metal cabinets and you used your own motor. About $150 or so as I recall. Guy was in California IRRC

Gunner

"[L]iberals are afraid to state what they truly believe in, for to do so would result in even less votes than they currently receive. Their methodology is to lie about their real agenda in the hopes of regaining power, at which point they will do whatever they damn well please. The problem is they have concealed and obfuscated for so long that, as a group, they themselves are no longer sure of their goals. They are a collection of wild-eyed splinter groups, all holding a grab-bag of dreams and wishes. Some want a Socialist, secular-humanist state, others the repeal of the Second Amendment. Some want same sex/different species marriage, others want voting rights for trees, fish, coal and bugs. Some want cradle to grave care and complete subservience to the government nanny state, others want a culture that walks in lockstep and speaks only with intonations of political correctness. I view the American liberals in much the same way I view the competing factions of Islamic fundamentalists. The latter hate each other to the core, and only join forces to attack the US or Israel. The former hate themselves to the core, and only join forces to attack George Bush and conservatives." --Ron Marr

You can't run a complete CNC machine from a VFD. It produces

Jon

If I get a CNC I'll upgrade the RPC I have now. It's on it's last leg ( Pun intended) I wanted the VFD for the Bridgeport, now knowing I'll nuke a CNC with it. It's the only three phase gear I presently own. I think it's 2hp. Ebay prices are all over on both RPC's and VFD's I was looking at the speed flexblility for the mill really. The CNC is in the future and I can get a item such as Ebay auction 330179518433 for the RPC. I have to spin up mine by hand now and all the heaters are jumpered.

Thanks guys,

Rob

Now were talkin'! EBay is getting out of hand with prices jacked up to cover seller fees. Any with digital controls to accommodate speed changes? Thanks again Iggy! I think it's a 2hp motor. Rob

You must have changed the motor, then!

You can either use the digital panel/keypad for control, or use a potentiometer. I have different drives also. I will include installation for free, since I would enjoy the process and chatting with you etc.

(D:) All of the above.

Three VFD's, the one for the coolant pump can be an itty bitty. A Jewelry store I know has a cute little VFD for a polishing "lathe" that's just a 1/6 HP 3PH Motor direct coupled to a three-jaw chuck.

-->--

I have run computers on VFD's without any problems! There was a time when HP made floppy disk drives driven by synchronous motors. Different pulleys were fitted for markets with different mains frequencies. We didn't know this until we took our UK (50Hz) sold HP 9845 computer to a power station in (60Hz) South Korea. HP couldn't source a 60Hz set of pulleys in time, so I bought an invertor and ran the computer and disk drives from that.

Remember that virtually all electronic power supplies have been switch mode for the last couple of decades. The only item that is likely to cause problems are the filters on the mains inlet of the electronics (if they are fitted). It is possible that the ground leakage currents from these will cause the VFD to trip!

Mark Rand RTFN

Rob

You moving to Joliet? Just wondering, as I happen to live there.

Regards Paul

Hey Iggy

I'm thinking about a VFD for my step pulley BP, don't remember motor size. I'll check in a few days and maybe we can work something out.

Paul --

----------------------------------------- It's a Linux world....well, it oughta be.

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According to Rob Fraser :

If you can split the spindle motor (which needs three phase) from the rest of the electronics for the CNC (which can *perhaps* be run from 120 VAC or 240 VAC single phase, then it is mostly a trick of where to mount the VFD and how to replace the motor switching with commands to the VFD.

What would be particularly nice would be if you can get the CNC to make use of the VFD for controlling motor speed as well as start/stop/reverse operations. Note that most VFDs can accept a 0-5VDC or

Good Luck, DoN.

Paul,

I'm here now... Been here since moving back from Chicago. Just have a shop there. Moving from River Glen to Timberline..... Neighbors there are NOT gonna like the funny car getting fired up in that prissy neighborhood! You close? I was born and raised here.

Rob

Many of the off-brand (Bandit, Centroid, and a few others whose names escape me at the moment) ran off single phase power except for the spindle motor. Bridgeport ran their BOSS stepper drive off a huge 3-phase transformer. If you do a retrofit, then you can select your own power source, and set up a VFD for the spindle.

Jon

I run mine on a VFD. Works great. I would put VFD on it even if I had real three phase.

On Sun, 28 Oct 2007 21:10:25 -0600, with neither quill nor qualm, Paul quickly quoth:

General Population or Solitary, Paul?

-- We have to fight them daily, like fleas, those many small worries about the morrow, for they sap our energies. -- Etty Hillesum