Need some help

[Hack]

I am in the process of building a home made verticle mill and have gotten to the point where I need to buy a motor for the spindle. I am using an R8 spindle and need something in the range of a 1.5-2hp motor to power it. I would like to get upto 4500 or 5000 RPM's out of it and would like to stay around 1 to 1 pulley ratio from the motor to the spindle.

I had my eyes on an 1100W motor and controller from keling, but poor reviews on this site have made me second guess that idea.

What I "think" I need is a BLDC servo motor and appropriate controller, power supply etc. I have machined a bracket based on a nema 34 motor size and would like to keep it if possible.

I will be using Mach 3 and want to control the spindle with the software. I would also like to tap with this machine if possible. Is it as simple as getting a servo motor, power supply and a gecko? What size servo equates to 1.5 - 2 hp (I know 746 watts is 1 hp, but do I want peak or continuous ratings?)

So my questions to all the the guru's out there, can anyone lead me in the proper direction of what I should be looking for? I don't mind looking, but I am not sure what I need to do what I mentioned above.

Budget is 5-6 hundred, maybe a bit more if needed. This will be going on an 1200 lb mill so I am not looking for "Wimpy".

Thanks in advance.

Dan

[Hack]

Any thoughts?

Thanks all.

[Al_The_Man]

I don't think you are going to get 1.5-2hp out of a size 34 motor.
I would use a vector rated motor that you can use with a VFD with pulse or encoder feedback up to 200hz.
Al.

[mike_Kilroy]

I 2nd Als comment and raise it one: 2hp probably will be larger than nema34 but I think your $ 5-600 for motor, feedback device, cables, drive that accepts step/dir to work with Mach3, is unrealistically low. If you said $ 1500-2000 I think I could quote you a set

[Hack]

Didn't realize it would be that steep. Now I could spend that if needed, but there has to be an alternative that I should explore.

I did a pretty long search for vector rated motors and came up with a few. The underlying theme with many of them I found was that they maxed out at to low of an rpm for what I want and they are to big for the area I had planned the motor to fit. Both obstacles could be overcome with pulleys and some new parts, but again if I don't have to I would rather not.

I did a search for nema 34 motors and came up with a couple. They are as follows:

QB034 motor7. This appears to have upto 846W continuous power and up to 1400 to 8000 rpm range. I could gear it down slightly with pulleys say 1 to 1.25 to get it slightly lower in the rpm range and a bit more torque.

Also, the blz36 is 1000 watts and good to 5000 rms..

Comments? Would these be any good?

[Al_The_Man]

The A.M. Nema 56 look like a candidate. The problem maybe getting a drive that accepts step/dir.
Unless you get an analogue convertor and go with AMC B100A40, used on ebay.
Al.

[PATMAC]

DAN I WAS LOOKING AT BUYING FROM THIS SITE CAN YOU SHARE WITH ME PRIVATELY IF YOU WILL I CANNOT AFFORRD TO MAKE AN EXPENSIVE MISTAKE

[Hack]

There is nothing wrong with ordering from Keling, it is the manufacture of the motor that is at fault. Keling has done a good job of giving refunds for the motors that they sold that are defective.

Read this thread for more information.

Motor Thread

[Hack]

Haven't lost site of this subject, just been trying to educate myself as to what I really want and need.

For some reason, I was initially thinking that I had to have a dc motor for this application. After some input here and looking around the net, that appears untrue. An AC motor can be just as good for variable speed applications. Ok so maybe I'm not so bright, but I have to learn sometime.

Most of the AC motors I have looked at are rated at 1800 rpms or so. I will be using some 1/4" and up end mills in aluminum and would like to see some decent rpms for that use. Looks like a 3/8" HSS cutter (2 flute) in aluminum with a .004 CL likes 3800 rpm and 30 ipm according the an online calculator. 1/4" even faster. So I feel for the best interest of the cutters, I should get 4500 rpms or so. I have also looked and this is the approx max rpm of my spindle as I will be using a modified minimill R8 Spindle.

Solution: 2 1/2 to 1 belt drive. Problem solved.

So to me an AC motor w/ variable speed that can be controlled with MACH3 and I can get upto 4500 RPM w/ belt drive and be about 1 1/2 hp or so would be ideal.

So who makes a kit that I can buy in a decent price range. Ok maybe it's not that easy, but if it is can someone point me in the right direction?

Thanks

Dan

[mike_Kilroy]

consider a perhaps better solution along the same lines:


AC 1.5hp TWO POLE motor rather than 4 pole: it goes 3600rpm base instead of 1800 so you get 2x the speed direct from the motor. THEN add a low cost VFD for speed control and you can go to 3600*1.5 on that motor directly by going upto 90hz. so you get to maybe 5400rpm max! No belts, no gearing up.

that said, a LOT of low cost motors are not balanced to run to 5400rpm; but some are. the ones that are not probably can get from 3600 to 4200 or so without too much worry - check with the motor mfger.

[Hack]

Did quite a bit more research over the past few days and have learned a bit about motors. Looks like an AC motor will be the most cost effective along with a VFD. The best place to shop (most online information) that I have found is Automation Direct.com

Looking at this motor It is 1 1/2 hp 3phase motor. Rated at 3600 RPM, with max of 7200. Minimum RPM is 349 as I read the specs. This does not have encoder feedback, but I am not sure that I need that feature.

For the drive, I am a bit more confused, but leaning towards this one.

Seems to match up to the motor well, but will it give me the on / off / speed control via Mach 3 that I am wanting? It has 6 digital inputs including forward / stop , reverse / stop, and multispeed. I assume this is what I need.

Are these a good match to my needs as well as each other?

What else will I need other then wiring / cables?

Can anyone give some feedback as to the good / bad / the ugly of these units I mentioned. Anything similar somewhere else that may be cheaper? Better?

Thanks

Dan

[mike_Kilroy]

good motor choice. gives u the speed range u want as factory rated.

not sure if the chinese vfd has db braking available or not - u should check close. w/o it coasting stopping from your 4-5000rpm may be longer than you want. personally I like the Hitachi drives better but your price would be higher from us than this one.