New Guy with electrical questions

[SShep71]

Hello All,

I am new to posting on this forum, I normally just read the threads. I need some advice on a project I am working on. I am building a custom Belt Grinder setup for tube notching and other metal fab. I am trying to find a motor that will work for what I want. I need 2 HP, appx. 3300 RPMs, and I need variable speed control. I have talked to a few places, but instead of advice I get a sales pitch. I was told to look into treadmill motors. I do not know if a treadmill motor will be enough. That is where the question comes in, what is the difference between a 2.5 HP DC treadmill motor and a larger 2 HP DC 56c frame motor (Baldor, GE, etc)? I really want/need rapid stock removal rates and I will need the power, but will the treadmill motor handle it? What suggestions would you make? I am building this for my garage at home so I am going to be limited by the bosswife on what I spend. Thanks a bunch

-Shep

 

[nine4gmc]

I don't know what the difference is in those two motors but what about using a 3 phase 2hp motor with a VFD? That would give you forward and reverse, along with speed control.

I did use a treadmill motor on a planer once and had to crank the speed all the way up to get it to spin, then back down to the speed I wanted to run it. It physically worked but was a pain in the *** each time I wanted to use it. They maintain decent torque at low and high speeds but once you get too slow, it shuts off.

 

[alfredeneuman]

+1 on the VFD idea.

It will convert your single phase to 3 phase. Get the "constant torque" type.
3 phase motors aren't as complicated as DC motors and require less maintenance.

I think that you might have less total invested with the VFD and motor than with the DC motor, the rectifier, and the control.

 

[SShep71]

I never heard of using 3 phase with a VFD, I will have to look into it. Any suggestions for that setup instead? Am I gaining or loosing by going that route?

 

[nine4gmc]

Plenty of people use VFD's when converting 3ph equipment so the prices are coming down. Plus, you can usually pick up a good used 3ph motor for relatively cheap since people think they are useless in a residential setting. The VFD will run you anywhere from $100-200 but it allows forward and reverse, plus speed control with constant torque as mentioned. I don't personally have one so I can't recommend a brand but it is high on my list so I have been keeping a finger on the pulse and picked up a couple 3ph motors already.

BTW VFD stands for variable frequency drive if you didn't google it yet. Here is an example of a 2hp version: http://www.ebay.com/itm/HIGH-QUALIT...271?pt=LH_DefaultDomain_0&hash=item2ec35503cf

You'll need to match or slightly oversize the VFD to the motor size. Like a 2-3 hp VFD with a 2hp motor. Don't get a smaller VFD than the motor hp.

Here is just one example of a VFD on a belt sander with a 3ph motor: http://www.knifenetwork.com/forum/showthread.php?t=59802

 

[TheEquineFencer]

I used a Siemens Micro master on the lathe and BP mill in the shop before the disaster. They do make VFD rated motors. It was fully adjustable and programmable for different motors. I ran 240 (1Ph) in and got 240 (3Ph) out. Some motors are not crazy about running really slow. I played with running small (1Ph) 240V and it ran those too.

 

[PT Doc]

nema 4 vfd would be good idea to protect the vfd innards. otherwise, you gaff to build an enclosure. get a3hp 3ph motor. you will bee all set.

I found that 3hp motor pricing is quite good. I think it's not in high demand compared to 2hp and less.

 

[theoldwizard1]

3 phase motors aren't as complicated as DC motors and require less maintenance.

That is because the "complicated" bits are in the VFD !

Still a good idea, especially if he can score a used 3 phase motor cheap. Those things last FOREVER !

 

[theoldwizard1]

The VFD will run you anywhere from $100-200 but it allows forward and reverse, plus speed control with constant torque as mentioned.

This is a big bonus in your application !

 

[Norcal]

I too recommend a 3 phase motor & VFD, have 3 machines that I used VFD's to power, 2 were 200 volt 3Ø that would have presented problems since only have 240V avail & the other had a odd frame size motor so the VFD worked well, VFD's 3 HP & smaller are pretty reasonable in price, paid under $200 shipped for one for a Rockwell HD wood shaper, the other option of replacing the motor would have been more $$.

 

[theoldwizard1]

Cheap !

3HP 3 Phase electric motor Like New - $120

 

[theoldwizard1]

I am building a custom Belt Grinder setup for tube notching and other metal fab.

This one looks nice

home made belt grinder/ tube notcher

I really want/need rapid stock removal rates and I will need the power.

If that is your priority, then forget the belt. You want to chuck a large end mill into the end of the motor and use a vice and lead screw to feed the work piece.

Home Made/Assembled End Mill Tube Notcher


What ever you decide, please post pictures of your build !

 

[SShep71]

I am looking into the 3 phase with VFD. I will post updates as I make progress.

 

[SShep71]

Hello all, I am still working on my mill project, but I wanted to know more about the VFD drives. The motor on the machine is an old 3 phase motor that works fin under three phase power. I have three phase now, but I dont know if I will always have three phase. I want to make it single phase compatible. It is a multi voltage 220/440 motor, I do not know the HP of it I will have to check tomorrow, but I think it is 2 HP. What suggestions are there for the VFDs, are there any to stay away from?

 

[nine4gmc]

From my understanding, you need AT LEAST the same hp rating but can go slightly over sized with the VFD. Check your actual motor rating and see, if it is a 2hp, you can go 2-3hp VFD. Maybe someone will chime in with brand names they currently use.

 

[SShep71]

I took a look at the motor again and there is no plate on there that state a HP rating, only that it is a Sterling motor and multi voltage with the line connection diagram. I emailed sterling and sent pics and I was told that it is NOT a VFD compatible motor. I never heard of that before. They said there is no way to determine the HP rating w/o the motor plate. So, from what I take it I now need a motor too.

 

[Rtw5150]

Throw an amprobe on it and you can figure out the HP.

 

[TheEquineFencer]

I took a look at the motor again and there is no plate on there that state a HP rating, only that it is a Sterling motor and multi voltage with the line connection diagram. I emailed sterling and sent pics and I was told that it is NOT a VFD compatible motor. I never heard of that before. They said there is no way to determine the HP rating w/o the motor plate. So, from what I take it I now need a motor too.

What state are you in?

 

[Falcon67]

I run a Teco 2HP on my 1HP 3 phase mill. Love it. New lathe is 2 HP 240 single. It'll be a while but I'll eventually change it over to a 3 phase. Programming is a bit cryptic, but I've spent time with some industrial controls so it made sense after a bit. That's usually the hard part - programming that is. VFD drives the motor directly, so that's not much of an effort.

Hope I never have to put the controls back on the mill - Chinese wire color coding is "red".