Odd question...

[Dave's_Not_Here]

... In my shop, I have a Legacy Mill used for architectural turnings. The company came put with a linear drive motor (per attached pdf file) to turn the lead screw. It attaches on the opposite end of the gear clusters so you can change the various gear sets.

As you see in the top picture, it looks to be a DC motor with a gear box to get the RPMs down to their advertised 0-120 RPM. In the second picture (sorry they are blurry) you can see the motor at the far end its relative size in relation to a 3.5HP router.

The company wants nearly $1,000 for the motor and drive control with two limit switches. I cannot justify that much money right now. I have spare VFD and DC Control units in my shop. What I need is a motor...

Now my question for you motor guru's with some imagination...

I can get low HP 3 phase motors fairly cheap, and DC motors are all over the board, including servos and steppers. Is it possible to have a DC servo with coupler attached to the lead screw and use one of my DC Controllers? I know that servos and steppers usually operate with a driver, but what I really want to do is use my speed controller and simply plug into my single phase shop outlet... and would like to avoid a gearbox but need to operate under 200 RPM... not too much to ask for, right?

Can this be done? What do I need to look for in a servo/stepper, what mod's need to be done to make it work with my controller, would I still need a driver, etc...

I have to believe I can do someting that is as effective or more so and not spend anywhere near $1,000.

Thanks in advance for any and all help...

Dave

[Al_The_Man]

From what I gather, you want to control the speed of the lead screw motor manually via an existing DC controller, If so the first question is what type of DC controller is it?
Motors and gearboxes can be had very cheaply on ebay, DC servo, AC servo, 3 phase induction etc.
I imagine the HP required is not high, especially if you use a gearbox.
If you operate without a gearbox, of course the HP size requirement for the motor will be higher and depends on what accel. decel. response you want.
If your Present DC controllers are simple phase angle controllers they may only operate in two quadrant so with this type you generally have to have a reversing switch, rather than For/Rev by potentiometer control.
I just picked up a Bison DC motor with gearbox brand new off ebay for $70.00. for a similar project.
Al.

[Dave's_Not_Here]

Al,

I have the following DC Controllers available and can get others:

Danfoss Vari-Speed 2000
2HP 240VAC, 20AMP - 0-180VDC - 10.8 AMP

KBRG 240D
1 HP 115VAC, 90VDC, 11-AMPS
or
2 HP 230VAC, 180VDC 11-AMPS

I also have an Hitachi 1/2 HP AC VFD available.

HP requirements are indeed not high.

The KBRG is a four quadrant controller and set for FWD/BRK/REV.

Can you show me the listing for the Bison you just bought?

I am guessing that I would have to use a transformer on some of the DC servos because of the lower VAC?

Would you be willing to assist me in my Ebay search?

Thanks!!

[Al_The_Man]

Dave, this is the same unit from the same seller 150039683190, I checked, I got mine for $49.00.
I can help in the search if you find anything or want to go with a particular motor type etc.
Al.

[Dave's_Not_Here]

Al,

Thanks for the offer of help, I will take all I can get.

I have no real preferance as far as motors. I am open to also looking at other DC Controllers that would be more compatible with a motor that has smaller requirements.

I will do some searches and if you want to as well, that would be great, then we can compare results and narrow down my parameters so I can focus on a handfull of options.

The mill uses a hand-crank system right now and I want to eliminate that and power up, but the maximum RPMs will be fairly low. Having a higher RPM available for straight line fluting, etc. is okay, but slowing down with the controller for roughing and spirals, is necessary... so motor/controller options can be built around that.

Thanks for your willingness to help me!!

Dave

[Dave's_Not_Here]

Al,

Here is an AC gear motor... will this work?
http://cgi.ebay.com/ws/eBayISAPI.dll...MakeTrack=true

Another Bison at an attractive price...
http://cgi.ebay.com/Bison-AC-Gearmot...QQcmdZViewItem

Will it work with my .5 HP Hitachi VFD?

RPM's are only in the 60 range, but I could live with it initially....

Thanks!

[Al_The_Man]

You perhaps need to spell out what top feed rate you need and the lead of the screw?
I assume there is not much torque required if you are hand cranking it direct drive?
Also is there much side thrust when moving in a cut?
Al.

[Al_The_Man]

Originally Posted by Dave's_Not_Here Here is an AC gear motor... will this work?

Unfortunately that is 1ph and you will need 3ph motor for VFD, and the VFD is probabally 220vac in.
Al.

[Dave's_Not_Here]

Al,

The Hitachi will take both 1ph and 3ph input and you are correct... it is 200V.

As for the lead, I would have to look it up.

As for side thrust, not much.

As for speed, at least 60 RPM and could could go as high as 300 +/- for straight line milling, but not a must.

Here is a DC motor with controller. The FWD/BRK/REV is available as an option. The Reverse is just to return the router to the starting point and not for any cutting.
http://cgi.ebay.com/ws/eBayISAPI.dll...MEWA%3AIT&rd=1

I inserted an additional link into the previous message... dod you see it?

Hope I am not bombarding you with data dumps...
Dave

[Dave's_Not_Here]

A Bison DC motor but not much data. Emailed the seller. The part number does not come up on the Bison site.

http://cgi.ebay.com/ws/eBayISAPI.dll...MEWA%3AIT&rd=1

[Al_The_Man]

The input to the VFD is 1phase but the output is 3phase, so you need a 3 ph motor.
The ebay link for the DC motor and control should work.(thats the one in post #9)
also what about something like this.
http://cgi.ebay.com/MT-5hp-Motor-wit...QQcmdZViewItem
for your VFD.
Al.

[Dave's_Not_Here]

Both the Bison in post #10 and the one above look to be right angle, though the Bison picture is too poor to be conclusive. I suppose I could mount it on a custom bracket and run it 90° opposite of the lead screw... Will have to check for clearance issues around the mill (loading materials, walking, etc.) since it would protrude out the side of the mill.

What if I removed the gear box and coupled the motor to the lead screw and used the speed controller to vary the RPM's???

The nice thing about the A.O. unit in post #9, is that it is a straight line install, comes with a controller that I can add FWD/BRK/REV to for about $60 or a FWD/STOP/REV switch for around $10 and looks like it will go for a good price.

What would be really cool is connecting the limit switches to the controller so it triggered the STOP function... but I am not an electrical guru in any sense of the word.

Thanks Al, I feel we are narrowing the field...