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View Full Version : A new toy is coming (VFD)



torker
01-09-2007, 08:52 AM
I finally made a decision about powering my ol' Ohio mill. I phoned the RPC dealer in Edmonton yesterday. Told him what I wanted etc. He asked me why I didn't want to use a VFD. Well...I had no idea why :D
He told me all the benefits etc. Told me that Grainger was one of their best customers up there. I guess anytime they have to install a smaller 3 ph machine in a single phase shop they just buy a VFD.
Hope I didn't make a mistake here....guess we'll see!
Russ

thistle
01-09-2007, 09:00 AM
you will find it has its advantages , especially if you wade through the instructions and use some of the many features.
you can also use the auxilliary control stripfor remote controls .

cadwiz
01-09-2007, 09:13 AM
Keep us posted on the outcome. Thanks to the responses on my mill restoration I'm now back to waffling over RPC vs VFD. Darin may have me a line on a shaper so I still may have to go RPC. We use VFD's at work for reactor agitator speed control and really like the benefits. Ahh, decisions, decisions....

Cadwiz

Magee
01-09-2007, 09:28 AM
Thistle's got it... I found the remote controls to be the biggest selling point... it did take a bunch of digging through the manual, some head scratching and a re-adjustment of my foil hat before I got it right, but it was well worth the effort in my opinion. I'm using it to run a 1980's era J-head and I hardly ever move the belts.... Just tap the "slower" or "faster" buttons.

torker
01-09-2007, 09:40 AM
Sounds good guys! I like the soft start...slow decel options and the auto braking is a big plus. I forgot about the remote options. He did mention it. I was just all tickled about the lil' keypad that you can mount on the machine.
It should be here this afternoon if the horse doesn't break his leg on the icy roads. Then in 6 months I should have it hooked up...lol!
Russ

Bill Pace
01-09-2007, 10:02 AM
Thistle's got it... I found the remote controls to be the biggest selling point... it did take a bunch of digging through the manual, some head scratching and a re-adjustment of my foil hat before I got it right, but it was well worth the effort in my opinion. I'm using it to run a 1980's era J-head and I hardly ever move the belts.... Just tap the "slower" or "faster" buttons.
I'll join in and say I'm a recent convert also. Put a Hitachi on my Birmingham 12x36 lathe wanting the variable speed capability and got even more...the thing is soo smoooth,--- power out the gazoo, ---lot cleaner cuts, lost most of that laddering/moire effect, and of course that wonderful ability to change speeds with a little knob, ---I'm really pleased with it.

>"did take a bunch of digging through the manual, some head scratching and a re-adjustment of my foil hat before I got it right"<

Hah, yeah, the manuals can be a bit much --- mine looks like a Sears catalog!

Am looking at one of ENCO's "Bridgeport clones" with 3ph and will definately use another VFD

Magee
01-09-2007, 10:03 AM
I think it would probably be a good idea to disable the stock switch on whatever machine you'll be running... VFD's don't like discharging rapidly (from what I've heard). ie: powering up the VFD with the machine switch off, then throwing the switch on = bad things. Again, this is just what I've heard. I didn't care to experiment.

Willy
01-09-2007, 10:32 AM
You won't be sorry Russ,with all of the features that a VFD has you'll be wondering why you didn't buy more for some of the other equipment in the shop.It's definitely the easiest and smoothest way to run a 3ph motor.I'm sure that you have already researched all of the features so I won't go into that,but I just wanted to say you didn't make a mistake going the VFD route,once you use one you'll wonder why most equipment doesn't come that way.
Don't forget to wire up a big red emergency stop button as well,ya won't need it often but it sure is handy when ya do.

thistle
01-09-2007, 11:24 AM
on my shaper , i have it set to accelerate slowly , if i have left the clutch in i can move to stop,or knock out the clutch.

also control of the motor can be done with the aux. strip and NO NC switches , as opposed to contactors .

thistle
01-09-2007, 11:27 AM
I am building a drill press out of odds an ends, i have as you said put a big red e stop near where my foot is. normally when stuff goes wrong on a drill you cant let go to get at the stop.
a foot, knee , or hip operated off button is a good idea

SGW
01-09-2007, 11:49 AM
Just about guaranteed you'll like it. As others have said, the documentation may be Obscure. The manual I got with mine certainly was, but with enough pondering I was able to find all the information I needed to set it up and install remote buttons. It was all there, just not presented well.

JeffKranz
01-09-2007, 12:25 PM
I started with a RPC in my shop and another member that I lives in the same town explained what a VFD will do. I have not added them to my Mill, Lathe and bandsaw. I must say pound for pound it was the best thing since slice bread, maybe it is even better than slice bread. I would not think of using one without adding the switches and pot to make it convient at the machine front. Now I just turn the little knob and away I go. No more changing belts unless I need to go to backgear. This is also the case on the lathe. The bandsaw now slow down for steel and speeds up for aluminum with just a twist of the knob. I liked them so much I bought 6 2HP units on Ebay and have plenty to spare.

I'm betting you couldn't be happier once it is hooked up.

Jeff

Here are three pictures. I used the forward/reverse switch on the lathe and the on/off switch on the bandsaw. On the mill I added a new box so I didn't need to reach the top mounted switch.

http://members.accesstoledo.com/beagly/keep/clausing.jpg

http://members.accesstoledo.com/beagly/keep/mill.jpg

http://members.accesstoledo.com/beagly/keep/bandsaw.jpg

Wirecutter
01-09-2007, 02:20 PM
I think it would probably be a good idea to disable the stock switch on whatever machine you'll be running... VFD's don't like discharging rapidly (from what I've heard). ie: powering up the VFD with the machine switch off, then throwing the switch on = bad things. Again, this is just what I've heard. I didn't care to experiment.

I didn't know this was dangerous, but I've tried this experiment. I have a VFD on my Bridgeport. Using the switch can work, but a lot of the time, the controller shuts down with an over-current fault. I can reset the fault and continue with everything fine, but normally, I just leave the switch on and let the VFD be the on/off, speed, and direction control.

I've read the manual on the VFD. It's got any number of safety features built in so it "plays nice" with the local wiring and my machine. I like the soft start and the decel features - it's easy on the machine. I don't use the machine's original switch anymore, though - the VFD is more convenient.

FWIW, the largest VFDs I've seen that turn single-phase into 3-phase are 3HP. Anything 3HP and below that needs to use single-phase power is best run with a (quiet, safe, versitile) VFD. IMHO. Above 3HP, you can still use a VFD, but you have to jump through hoops.

-Mark

Ausserdog
01-09-2007, 03:07 PM
My J head BP (with shaper head too) and shaper are run off of the same VFD. Just used twist-lock plugs and can then swap it around. Plus a VFD is alot smaller than a RPC. I've got so little room in my shop / garage that I've got 3 cars double stacked. I haven't seen the floor in years. :D

Yucholian
01-09-2007, 03:42 PM
I took the same route and got a VFD for my 3HP mill. http://www.yucholian.com/metalwk/metalwk.htm

gundog
01-09-2007, 04:50 PM
How much do these VFD cost. I have my Wells Index running on a static converter and I also have a nice 3 1 hp motor I would like to move to the SB 10 K if I keep her.
Mike

SGW
01-09-2007, 04:57 PM
See, for example, www.dealerselectric.com and www.vfds.com (usual disclaimers). Other folks have additional links, I'm sure.

Bill Pace
01-09-2007, 05:17 PM
How much do these VFD cost. I have my Wells Index running on a static converter and I .......
Mike


Gun.........
They come in all sizes & shapes (& cost)........this is the one I got--

http://cgi.ebay.com/2-HP-VFD-VARIABLE-FREQUENCY-AC-MOTOR-SPEED-DRIVE_W0QQitemZ130066976414QQihZ003QQcategoryZ7139 3QQrdZ1QQcmdZViewItem

lazlo
01-09-2007, 05:57 PM
Torker: another big advantage of VFD's is that you can use a braking resistor to stop (and reverse) the spindle almost instantly. On a mill, this is great for power tapping.

I have a mechanical clutch/brake on my Clausing lathe, but I wired-up a 2 HP braking resistor to build an Electronic Leadscrew Reverse mechanism like the Monarch 10EE.

The braking resistors are expensive if you buy them from a VFD dealer, but they sell for the price of shipping on Ebay all the time...

JeffKranz
01-09-2007, 06:22 PM
Mike,

I have a couple of 2HP available units made by Mitsubishi. These will take single phase 220 and output 3 phase 220 volts. On these units, you set all the parameters using a keypad and once everything is working OK, you can remove the keypad. I think it is a must to add three momentary switches for Forward, Reverse, and Stop. Then you add one Pot for speed control. Make a little control box and run some wires and you are off to the races. If interested email me at kranzj@bex dot net.

Jeff

thistle
01-09-2007, 08:21 PM
I have a 2 hp fm100 from dealers that i am going to stick on my Wells Index machine, i need to build a box for all the control buttons ,on off reverse coolant , lights ect -more stuff to do......

Yucholian
01-09-2007, 08:43 PM
How much do these VFD cost. I have my Wells Index running on a static converter and I also have a nice 3 1 hp motor I would like to move to the SB 10 K if I keep her.
Mike

It depends, if you want a good VFD for around 3HP motor, will cost between $250 and $300. If you want a sensorless vector VFD (supposedly better torque and other stuff), $350.

Bill Pace
01-09-2007, 08:48 PM
Mike,

I have a couple of 2HP available units made by Mitsubishi. These will take single phase 220 and output 3 phase 220 volts. On these units, you set all the parameters using a keypad and once everything is working OK, you can remove the keypad. I think it is a must to add three momentary switches for Forward, Reverse, and Stop. Then you add one Pot for speed control. Make a little control box and run some wires and you are off to the races. If interested email me at kranzj@bex dot com.

Jeff


Jeff--- trying to contact you about the VFDs and keeps getting kicked back, would you contact me, or give your email again......

Bill

wierdscience
01-09-2007, 08:51 PM
Sounds good guys! I like the soft start...slow decel options and the auto braking is a big plus.

Russ,your not going"Metro" on us are you?:D I like snap starts,it's just like having real three phase,you can spin a chuck right off a threaded spindle in reverse:D

Dawai
01-09-2007, 09:04 PM
Okay ground rules..

read up on starts per minute (heat dissipation)
AND DB or dynamic braking which also build heat.. it holds power on a leg and shuts the generated power from the motor into dump resistors. Hitting estop on my mill can slam in the brake on the head making it DB bus over volt trip.

Programming is the worst thing about the inverters.. normall you just need a few of the parameters.. but read the whole book.. Current limit should be set to the motor nameplate. You just toggle through the menus and enter pre determined values.. which you get from reading the book.

ANd.. THE INTERNAL voltage in the inverter which controlls start, stop and speed refrence.. do not use anything except a isolated device.. be very careful if you use other switch contacts to control other things. putting external voltages into the inverter can kill it dead.

CNC? make sure the snubber resistor-capacitor are removed from either the motor connection box or the overloads in the cabinet..

A ten turn pot, yeah.. it gives you much more control.. cost about $10 more.
With a bridgeport like mine with the varispeed head it is redundant mostly.

If you get cheap? you can wire a twist lock onto the output of the inverter and run other machines with it like I do. (cheap).. a twistlock is about $20 per plug so if you don't have them.. it gets almost as cheap to buy more inverters.

Another thing? the inverter is sitting there idling when not enabled.. you can get quite a nasty shock from the t1,2,3 leads.. Transistor leakage. AND I turn off the power to my inverter, my cnc table in the bridgeport when estopped because I don't trust lightning didn't hit a pole across town and short out them lil on-off transistors.. especially before I grab the endmill to change it. Bill gates had control over my inverter for a while.. I got it hardwired again now.. I flip the estop,it positively can not run. Before if the computer rebooted as the machine was idling, bill turned on the parallel port bits and the inverter came on.. No matter I was changing endmills.

nheng
01-09-2007, 09:45 PM
You'll love the VFD. I use it for threading using the forward and reverse functions and about 1 second on accel and decel settings. The fan on my 3HP lathe motor is about 70% quieter by simply running the motor at about 60 - 70% of normal speed.

Two things to consider (maybe the first is not valid for mills ??). If you have a splash lube gearbox, it's probably a good idea to run at a speed at least adequate for the lube to get around.

The second thing that is still holding me up is that on some VFDs, and e-stop is not necessarily waiting for you on the wiring strip. In a Hitachi, for instance, you'd have to wire the e-stop to open the common for the forward and reverse functions.

Some e-stops cut all power but with the VFD, you'd lose your brake.

Dawai
01-10-2007, 12:45 AM
Ok.. you mean the dynamic braking.. not the other one?

If you turn the db up to stop too fast you are asking for trouble with heat. External resistors are needed to do that a lot.

torker
01-11-2007, 03:18 PM
Russ,your not going"Metro" on us are you?:D I like snap starts,it's just like having real three phase,you can spin a chuck right off a threaded spindle in reverse:D
LOL! Yup...Metro it is! I have this lil' gem in my grubby mitt right now. I see what you guys mean about the manual. Thing has far more functions than the salesguy mentioned also.
Just had a quick look but I'm not really seeing how the motor is to be wired through the mag start switch. I'm not touching anything until I get this all sorted out. I seem to remember the guy asking me a bout a mag start switch but I didn't think it had one. I took the funny "junction box" apart this morning and found out that it does indeed have a mag start. Hope this doesn't screw up whether I can use this on this motor.
Ummm...I have a lot of reading to do I guess!
Russ

Magee
01-11-2007, 03:25 PM
Unless I'm mistaken I believe you'll be looking to bypass the mag-start and tie the VFD directly into the T1, T2, T3 and ground lines on the motor...

I'd remove the mag start and replace it with an enclosure of the appropriate size to house run, stop, Estop, speed pot, etc.

torker
01-11-2007, 03:37 PM
Unless I'm mistaken I believe you'll be looking to bypass the mag-start and tie the VFD directly into the T1, T2, T3 and ground lines on the motor...

I'd remove the mag start and replace it with an enclosure of the appropriate size to house run, stop, Estop, speed pot, etc.
Thanks! I about had a fit when I saw all the wires coming out of the motor etc.....there's waay more than I ready for. Going to be a sit down and read project...after the LAST night shift tonight(yep...I'm excited about that!). This weekend I'll get into it. My newly made drive belt will be here by then so the thing may actually make clanking noises soon :D
Russ