Old grinder VFD/motor upgrade.

anvilring

anvilring

Joined
Nov 29, 2000
Messages
2,869
I have an old grinder made in the early to mid 80's and for the life of me can't remember the maker and I've met the guy! He was up in central Texas, some west of Jefferson and my Uncle bought it from him new. I've had it since 2002 or there'bouts and I actually loaded it in my pickup and took it to this guy's house to see if it could be made to run right; it has never had, or seems to be unable to produce any power and is easily stopped. I've seen other 1hp grinders that had more "umph" than this one. Turned out he was by then into making musical instruments and had abandoned the grinder biz. Said it would have to have a new motor and vfd but he wasn't up for doing it.
For years now I've just used it for light stuff and 3M belts (you can stop those too but they will still work) however now I'd like to either put on a new/better VFD controller, or a new controller and 2hp motor. So my question to those that know, what should I try first?

(1) Use the existing motor and get a new vfd and if so, some suggestions please w/links if possible?
(2) A new motor AND vfd made/designed for one another and again; w/ some suggestions. and links perhaps for purchase.

In my pic album you will see the drive wheel is 8" or 8.5" and has only a 1/2" shaft hole. If it's a new motor that's decided on, where can I get someone to bore out that existing drive wheel to 3/4"? or should I get a new drive wheel as well? the machine frame is I believe, a "C" frame correct?
This old machine is made well and, w/the right new "whatever it needs" I think will work well for me again.

https://www.flickr.com/photos/19089828@N00/albums/72157716271181092

20201004_110541 by rynegold, on Flickr
20201004_110546 by rynegold, on Flickr
20201004_110550 by rynegold, on Flickr
20201004_113317 by rynegold, on Flickr
20201004_131131 by rynegold, on Flickr
 
You know I think your right... I didn't measure it but will and post what I find later. I'll bet your right.
 
I found a data sheet online that says it's a 5/8" shaft. You can get a 1.5 HP TEFC 3-phase 56C motor and a KBAC-27D drive if you want to run on 110V. A four pole motor has a synchronous speed of 1800rpm. You can adjust the maximum frequency in the drive to top out around 2,500rpm via potentiometers. There are many different options, depends on how much you want to spend. The KBAC is dust proof, you just hook it up and go. They are around $350 or so. A popular motor option that does not break the bank is the Iron Horse motor from Automation Direct.
 
That's a DC motor and a DC controller


You cannot mix te AC/DC, you cannot use a VFD on a DC motor and vice versa


Have you ever read the manual for that controller ?
How is is powered, what are you plugging it into? 110 or 220 vac

There may be jumpers inside that are limiting hp. like a HP jumper.


In the end, it's only a 1 Hp motor
If you want to make a change, a kbac27d and a new 2 HP, 3 phase AC motor to match would work.


Link the manual, crack it open and show photos of the insides.
 
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I do not have three phase, only standard 120v out in my shop. So the KBAC is for three phase? See, this is why this is so confusing to me. I really don't understand it. So what kind of controller would I need for this motor I already have? As noted above, a VFD will not work with it correct?

Probably seven or eight years ago, the controller stopped working completely, and somehow, I managed to get a new board for it and installed it. And that still didn't really help matter as much. So do you have a link to where you can buy this controller motor setup for 110 v? is there already a thread somewhere established here in shop talk that discusses all this and makes recommendations? I would just like to get something out of my old machine and I don't mind spending money on it, I do two horsepower motor and drive I could use with any of the newer frames right? I mean if I wanted to swap it all out completely? like I could use that motor and VFD with the Northridge correct? I've actually thought of buying one of those.

edit: some questions....
Are you telling me I shouldn't be running a dc motor w/120v AC? So is that why it's so underpowered? Or is my/a DC drive converting AC to DC? Truthfully, I think my drive is fried or, just old.
I actually have a really nice 1/5hp DC motor not in use. Can I use it w/this machine? and if so, what/where would I get a drive for it? How well would that work?
 
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Your controller is converting the 120VAC to DC voltage and allowing variable speed control. The 1hp motor "should" be enough for decent grinding with the contact wheel.

The KBAC (and other cheap Chinese VFD) are running on 1 ph (single phase) and converting to 3 phase voltage to run a standard 3 ph motor. Typically you would purchase a 3 ph, 240/460 motor to use with the VFD. The KBAC (around $350 sounds about right price) is about the only VFD that will convert 1ph 120vac to 3 ph, 240 volt. The cheaper Chinese VFD (around $70 to $100) will only convert 220 (same as 240) to 3 ph. The 240/460 vac motor is wired for either low (240) or high (460) voltage for use. The KBAC is a NEMA 4 enclosure (dust proof) while the Chinese are NEMA 1 and will require either mounting in a box or putting filters over the air inlet to prevent metal grinder dust for causing problems.

Yes, since that is a 56C mounting on the grinder, any 56C frame motor will work just fine, anything from a budget Iron Horse to a Belfour motor, and use any of the 3 ph VFD drive.
 
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The KBAC will plug into single phase current you have and convert it to 3 phase , this is what allows you to have variable speed.

If you want to use a dc motor you will need a dc controler ,if you use ac motor you can use a 3 phase motor and use a vfd ... or you could just use a single phase motor and a simple switch if you didnt want/need variable speed.
 
I don't know of a good way to figure out whether your problems are due to the motor or the drive. It's easy to check the brushes and make sure the bearings are turning freely. If it is not anything obvious, I would replace both the motor and the drive. There are many options. You can go either DC motor + DC controller, or 3-phase AC motor and VFD. It really depends on your budget and how much time you want to put into the project. Here are some of them with subjective ratings:
  • Best option: KBAC 27D drive (~$350) plus 4-pole 2HP motor (~$200 for a budget motor, $400+ for US name brand). This drive can run on 110V at 1.5 HP or the full 2 HP on 220V. Wiring, cable glands and a reverse switch will add about $50. The drive is dust proof, easy to wire and just works. I have two of them and really like them.
  • Good option: KBAC 24D drive (~$240) + 4-pole 1HP motor ($150). This will run on 110V and will have the same performance as your grinder had in its glory days.
  • Budget option: Generic VFD from China (~$100) + 4-pole 2HP motor ($200). The downsides are that it requires 220V and you have to make your own dust proof enclosure.
  • DC motor + DC drive: I have not used this combination.
If you buy a motor, double-check the OD, there is very little clearance. I am not sure if the OD is standardized.
 
Here are pics of my controller box interior. Also a 1.5hp DC motor I found out in my shop. The shaft diameter is huge. I would have to have someone bore out my 8-in drive wheel or, buy a new one. Where would I get that done? I don't have a machine shop with that capability handy.


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