Rockwell Horz./Vert. Combo Mill - Wiring w/VFD

I've been reading on here for about as long as I have been looking for a Rockwell combo-mill. Well, I finally came across one and I picked it up. Probably paid more than I wanted to, but I'm sure I'll be happy with it once I get set up. With that said, I will start off showing what little I know, so if remarks are to be made, lets get them over with... I'm tough skinned, so you probably won't offend. Being a combo machine, it has TWO motors. The horizontal has a 1 1/2 hp while the vertical head has a 1/2 hp motor. (See Pics) Although the PO had a RPC hooked up in his garage, I think I'm leaning towards a VFD.... My questions are as follows:

I will be utilizing both the horz/vert options with this mill.
Can ONE VFD run both motors since both have different parameters (amps)?
For simplicity, am I looking at two VFD's to run both motors? Suggestions?
Preferably, I'd like to have one control box (On/Off/Speed), is this possible even if I went with dual VFD's?

I'm not sure how much of the electrical is original. When switching to a VFD, how much of it gets bypassed?
Although I'm conceding to hiring someone, it must be the right person. If there are any suggestions, information, links or reads, please let me know. There's a WEALTH of information, I'm just a little overwhelmed with it all.

My apologies - but I am posting this on another forum - so if it looks familiar...

If anyone has any recommendations for the So. Cal. Area, please PM or send me the info.

On a Bridgeport type mill there is a main spindle motor on top and a secondary (smaller)feed motor for the table. Your mill is a little different. You could install two VFD's but I would not. I would input a fixed frequency into the electricals and use the stock speed controls, probably like the original owner was doing with the RPC.

Before I type any more, some questions:
What direction of travel does that lower motor provide?
Will you use it often?

Rons _ thanks for the reply. I am not quite sure I understand your question. The lower motor is the 1 1/2 HP for using the horizontal mill. The collets used by the horizontal Rockwell are NMTB 30. It's totally separate than the vertical motor (1/2 HP) which utilizes the R8 collets. I will pursue hooking up BOTH motors and have them ready for whatever use I need. It's been my experience that it's sometimes "easier" to set-up/clamp to the table. Easier might NOT be the best way to describe it, but it was a PLUS for me to come across the combo.

The more I read on this, the more I am getting closer to have someone do this for me. If anyone knows of someone who does this type of work around Orange County, CA, please Please let me know. I think I am leaning torwards having TWO VFD controllers.....

Oh, I see it now. The first picture shows the horizontal mill opening for collets, the second and third picture do not. Da.

It looks like you are either going to have a horizontal cut or a vertical cut setup at a time. Are some VFD's designed with multiple motor parameters, such as setup A, setup B, etc. A 2 Hp VFD with two program parameters, that is for two motors, is not a big deal to me. You should look at some on-line VFD manuals. The only differences between two motors are:

Full Load Amps
HP

The dual motor setup does not appear to be standard in all VFD's. Something you can think about. You would also have to have a way to connect either A or B motor terminals. Not a big deal. But since some of those Teco VFD's are between $100-$200, probably just installing a dedicated VFD for each motor is easier.

How To Set Up Multiple Motors On One Drive - A GalcoTV Tech Tip - YouTube

If you don't like the idea, at least the lady is not too bad of a view.

Man, I used to make fun of guys who "flipped-flopped".... The last two days, I've gone back and forth between the RPC and VFD's more times than I'd like to admit. Although I just ordered the popular FM50 202-C. In speaking with the tech support, it was SUGGESTED I could wire accordingly, and then have the VFD power a receptical that I could plug either motor into. Sounded great. It was also suggested that I could use a "thermal overload" to the smaller 1/2hp motor using the 2hp VFD. This "thermal overload" would be between receptical and 1/2 HP motor. But looking at prices of these, they're about the same as a 1/2 hp VFD. Does anyone have a suggestion or advice? I don't mind plugging in either motor prior to using it. I seriously doubt it would be a everyday type of chore. Is there a "cheaper" way to hook up protection for the 1/2hp motor while using a 2hp VFD. I think the 1/2hp VFD is about $110.

TIA

CrimsnTide said:

Man, I used to make fun of guys who "flipped-flopped".... The last two days, I've gone back and forth between the RPC and VFD's more times than I'd like to admit. Although I just ordered the popular FM50 202-C. In speaking with the tech support, it was SUGGESTED I could wire accordingly, and then have the VFD power a receptical that I could plug either motor into. Sounded great. It was also suggested that I could use a "thermal overload" to the smaller 1/2hp motor using the 2hp VFD. This "thermal overload" would be between receptical and 1/2 HP motor. But looking at prices of these, they're about the same as a 1/2 hp VFD. Does anyone have a suggestion or advice? I don't mind plugging in either motor prior to using it. I seriously doubt it would be a everyday type of chore. Is there a "cheaper" way to hook up protection for the 1/2hp motor while using a 2hp VFD. I think the 1/2hp VFD is about $110.

TIA

Click to expand...

I would be concerned about using the 2Hp rated VFD on a 1/2 hp motor without limiting the output current of the VFD. The output of a VFD needs to connected directly to the motor, so to answer one of your questions, all switches and controls connected to the motor should be removed and the output of the VFD needs to go directly to the motor. If you place a twist receptacle at the output of the VFD so you can connect different motors to the VFD, please make sure a motor is connected prior to pushing the run button. I had a customer place a VFD to the inputs of his machine and not directly to the motor. While the VFD was operating and sending current to the machine, the customer turn off the machine at the controls of the machine. The current leaving the VFD saw an open circuit and went straight back into the wrong end of the VFD. He called me the next day to order a new drive and told me he had to pick up a fire extinguisher because the VFD flamed. If you do not have a motor on the output of the VFD and accidentally hit the run button. Bad things can happen.

The other concern is the current output of the drive. The FM50 you referred to has an output current of 7.5 amps. This is significantly higher than the current rating of your 1/2 Hp motor. Motors are dumb and should a large load be placed on the spindle, the motor will ask for more current to turn the spindle. If you do not limit the output current of the VFD, either by changing the output current parameter each time you change motors, or placing the correct thermal overload or thermal protection to the smaller motor, the drive could send too much current to the motor and damage the motor.

Using a RPC is the easiest way to get phase conversion, but at these size motors may be more expensive than two VFDs. The one larger VFD can be used to run both motors, but you will need to make sure that all safety precautions are taken before hitting the run button. The safest method for both phase conversion and motor speed control for each method would be to purchase two VFDs sized appropriately for each motor and run them independently. The overall easiest way to get phase conversion would be to purchase a RPC and connect it to the machine and use all the current controls on the machine, but the ultimate decision would be your comfort with wiring, the need for speed control and your wallet.

Flip-flopping is a good thing when you are deciding.

A thermal overload (used) is cheap, like $10 - $30. I have seen what you are describing. The overload is just the part that is attached to a motor starter. You run the three phase wires thru the overload block and then to the 1/2 Hp motor. The contact wires from the block are connected to the appropriate input connections on the VFD. NO BIG DEAL and NO BIG COST.

But...
Take a Bridgeport type mill with a table feed motor of about 1/2 Hp that runs from the main 3 phase power from a RPC or a VFD. There is no motor overload protection built-in. You have to add it for the smaller motor. I don't think many people do it. Probably because the smaller motor is not run often, or long enough.

So...
In your case I think it is better to have the protection since the 1/2 Hp motor is going to be used on the vertical cutting configuration.

The 2 plug idea is something you could do. Their suggestion implies that you do not have to change any motor parameters on the VFD. You would need a enclosure box, the VFD, and a overload block.

I appreciate the reply's. I have considered each one and after thinking on it. I have decide to purchase a SECOND VFD to run my vertical motor (1/2 hp). So, I have purchased a FM50-202 to run my 1 1/2 HP vertical motor and a FM50-201 to run 1/2 HP vertical motor. So with this, it has me asking for more help/suggestions. I'm going to try and write this clear and concise, but I usually fail miserably at this. My ULTIMATE goal will be to have ONE external switch panel that will include the basics of 1. Power 2. FWD/Rev 3. Variable Speed/Potentiometer 4. STOP button.

From the other end, here's my thoughts.
From my sub-panel, I'm HOPING to get by with a 15 amp breaker.
From there it gets wired to a Square D safety switch. Square D 3 Amp 24-Volt 2-Pole Indoor Light Duty Safety Switch with Neutral-L221N - The Home Depot
From the safety switch, I have a 10 ga. SO cable with a 20 amp FEMALE twist lock plug: 2353 > Black & White Plugs and Connectors > Electrical Wiring Devices > Products from Leviton Electrical and Electronic Products
I have a large junction box I want to house BOTH VFD's in. Each VFD will be wired SEPARATELY with a MALE 20 amp Industrial Grade Locking Flanged Inlet: 2355 > Flanged Inlets > Locking Wiring Devices > Electrical Wiring Devices > Products from Leviton Electrical and Electronic Products
Again, EACH VFD will be wired separately to accept a 220v 1 phase feed and only powered when I plug the power cord into whatever receptacle is needed.
Each VFD will be wired to it's "matching" motor.

I think I have this handled or properly thought out to my "ability". Although it may seem like a PITA to switch or unplug to go to another motor, I don't feel I will be doing it that often... However, this is where I'm a little fuzzy.

Can this be done safely? Does ANYONE know what conditions must be met with the VFD's? Are they "Hot Swap-able"? Are there conditions to meet BEFORE I can plug one in - hot?

Also, from my EXTERNAL control box. I only want ONE. I am perfectly capable of making up a serial type plug for BOTH VFD's - if needed. They would be wire identically. So my question would be this, can the controls be wired in a "series" so I don't have to wire up two times - meaning can I wire from the external control box going to the first VFD and then run the "control" wire to the next VFD. Make sense? Again, I COULD have TWO serial like plugs for each VFD and plug my external "remote" into whichever VFD I wish to control, but if I can run the power, FWD/Rev. wires only once... I guess my question is will the external control wiring BOTHER/DAMAGE the VFD that is NOT powered?

I am electrically inept. I wish I could wire up something fancy to make the home hobbyist's proud, but it's beyond my capabilities.... Sorry for the long drawn out post. but it's kind of a special needs machine. I chose NOT to go with a RPC, so I'm looking to make this as simple, but functional as I possibly can.

Any help or suggestions will be much appreciated....

Or am I OVERTHINKING this and making it complicated?

Could I wire to a terminal block (strip) right inside the Junction bock where the VFD's will be housed? From there just wire BOTH VFD's up with incoming220v power? This would make them both under power at the same time.

I can then wire each motor to it's own individual VFD...

Is the TECO FM50 capable of switching ON/OFF from a remote switch - using maybe something like a selector switch?

Anyone?

I'm going to try and figure out the manual - again....

Thought I'd ask here too...

O.K., a little more help, PLEASE. Is there way to power an external fan with the VFD??? I have a few enclosure fans.
If so, what would be the ticket - 24v? 12v? I think most all of them draw less than a 1/2 amp?

Thanks again!

As to the fan, look at surplus places. 220V muffin fans are readily available surplus. A little more expensive, but will be simpler.

No experience with this place, just the first google link for an example:

http://www.surplussales.com/fans-blowers/fansblow-3.html

Several on the page.

Comair Rotron MX3A1 Muffin Fan
220 - 230v AC / 98 - 115 cfm
(FAN) 028326
Comair Rotron MX3A1 muffin fan. 98 / 115 cfm. 220 / 230 vac, 0.10 / 0.09 amp, 50/60 Hz, 4-5/8" (119 mm) square x 1-1/2" deep. High quality aluminum housing, plastic blade. Sleeve bearing. Aluminum frame. Brand new!!

When you have several motors, and with the fan you are now up to three, it can be easier to use an RPC. (but the RPC would need no fan)

Both methods give you 3 phase power.

VFDs add variable speed to basic 3 phase power.

VFDs do require changing the machine controls, and rigging up a "control box"..

VFDs are generally "one motor one VFD", although you can operate two motors at different times with one.

VFDs are complicated, and best bought new to avoid problems.

RPCs are simpler to deal with, since you can use existing 3 phase motors and controls

RPCs are basically "plug and play", there are NO changes to the machines unless you need to change motor voltage from 480 to 240, etc.

RPCs can be made, but they can also be bought. Bought new, or bought used..... they are rugged, and simple, used is not generally any big risk.

An RPC can power any number of machines up to their rated HP, whether one at a time, or several at once.

In your place, I would consider an RPC. The VFD may not give you any big advantage, and you have the issue of bypassing machine controls, setting up new controls, mounting and enclosing them, etc. The RPC can be set somewhere and will just work.

If variable speed is that important, maybe the VFD is needed. But if not, and I am betting it is not, then why go to the hassle of converting when an RPC will power a 3 phase machine just the way it is now?

You can do something better than just a DC fan.

With a Mosfet, potentiometer, and thermistor you can have the fan speed regulated to the heat on your VFD heat sink.







I use three thermistors here because the power supplies I used this circuit with have three points of heat (three transistors). One of them is inside the yellow jacket of the lug on one transistor case.
You can just use one thermistor.