Brown & Sharp Surface Grinder

[Robo_Pi]

Thanks Dabbler, I figured it could be done. I guess the key is to make sure all the motors used have very similar characteristics.

I mean, Bob is certainly right. It's not advisable to do this unless a person really knows what they are doing. But there's the key.

As long as you know what you're doing it should be just fine. Just gotta make sure all the motors are compatible. In fact, sometimes you can trick the controller into thinking that incompatible motors are actually the same by adding inductive or restive components. That gets into a bit of electronic wizardry, but it's often doable. I build robots and I'm always tricking the micro-controllers or motor drivers into thinking their driving something their not actually driving.

 

[Bob Korves]

Do as I say, not as I do...

 

[Robo_Pi]

Here's a guy who hooked up two motors to one VFD permanently using long cables and permanent switch mounted on the wall.

Part 1:

Part 2:

As he points out you can use this for as many motors as you want. Just make sure that only one motor is connected at any given time. To have multiple motors you'd probably need a large rotary switch that will only allow one motor to be connected at a time. That way you could never accidentally have two motors switched on simultaneously.

The final thing to be sure of is that all the motors are electrically compatible so that the VFD only needs to be initially adjusted for that single type of motor.

Sounds good to me.

 

[Robo_Pi]

Here's a lady that has a controller that can drive different sized motors.

So apparently there are plenty of options available for driving these motors. I was originally thinking to just convert everything over to 110v/220v motors. But maybe sticking with the 3-phase might be the better option after all.

I could probably even build my own VFD from scratch. If that's the case I might just go ahead and build three VFD's custom designed for each machine.

I'll cross the motor drive bridge when I come to it.

 

[Robo_Pi]

I went out and dug up the 3 phase motor I have laying around in one of my shops. A fellow gave me this a couple years ago. Based on the oil cups I'm willing to bet that it's quite antique. It doesn't look like much but it spins like a Swiss Watch.

This is a bit off-topic, but I don't think anyone cares.



Both end bearings have these really nice oil cups.



I'll bet this baby will run smooth. It certainly turns effortlessly and quietly.



Even though it's a fairly large motor it's only 1-1/2 HP. 1725 RPM , 3 PH, 220 Volts, and draws up to 4.2 AMPS.

Since I have this motor I can experiment with it. Maybe I'll try building my own homemade VFD to drive it. It will be a learning experience. I just watched a bunch of videos on how to control a VFD using an Arduino. I have tons of Arduinos laying around. I can fix this motor up and program it to do whatever I want. I'm sure I can put it to use.

When the fellow gave it to me I was thinking I would either scrap it or sell it. But now I think I'll use it as an educational tool and maybe make some kind of new toy with it. In fact, I have a hand-crank bead roller that I would like to motorize. This motor is really overkill for that. I was originally thinking of using a variable speed 1/2" drill to power the bead roller. This fellow would make that bead roller into a monster.

I'll clean this motor up and see if I can build a VFD for it from scratch. That's the best way to deal with this kind of stuff. I'll learn how to build a VFD and look out! Who knows where I'll go after that?

 

[Dabbler]

I love the 'old iron' motors! I have one from 1930 that my dad used on his first table saw. It still runs fine!

 

[Robo_Pi]

Well this one sure turns smoothly enough. It feels like a brand new motor. It doesn't look very new. But it sure feels new.

I'm surprised that it's only 1-1/2 HP though. When I first dug it out I was thinking it must be huge like 5 HP or something. It's pretty big. I guess that's because it's so old. They built them big back then. I'll bet it has a lot of torque though.

I'll clean this baby up when the weather gets warm. I'll want to do this outside, it's going to need a good wire brushing to clean it up nice.

I almost hate to disassemble it, but that would be the best way to give it a really good cleaning. But it turns so smooth as is. Might be better off to just leave it assembled and just blow it out with air the best I can.

Edit to add,...

I was just thinking,... look at the double V-belt pulley. It must have massive torque if it needs two V-Belts. It would probably twist my hand-crank bead roller up like a pretzel. I'd definitely need to have a good controller on this motor. If it came on full blast it could be one dangerous beast.

 

[Dabbler]

The size may be because it might be a repulsion-start motor, which needed room for the windings.

A point of note: The older motors used oillite bushings. My Dad used to remove and reimpregnate the oilite bushings every 15 years or so, because they dry out, and collect grit et cetera... If yours is low hours it may be smooth because the bushings haven't worn out yet.

They also had massive start torque at a cost of an enormous inrush current... Thye usually hovered around 80% efficient when under load, where a modern motor can be over 95%.

 

[Robo_Pi]

Efficiency won't be important for all the more I'd ever use it. But that could be a big deal for a company that's running a lot of motors 24/7.

Using this on my bead roller would be silly. I'm probably better off sticking with the half-inch drill idea for that project. But I do have another project I could use this for. Again, probably overkill. I have a set of drums that I want to build a rotating base for. Kind of like a merry-go-round that will support the whole set of drums and drummer. I've had this idea for a while.

What it amounts to is that I have a deck on the side of my cottage between the front yard and back yard. And I leave the drums set up on the deck. Sometimes we play in the back yard. So we turn the drum kit around to face the back yard. And sometime we play in the front yard. so we have to turn the drum kit around to face the front yard. And often we'll do this in the same day. We might play in the back yard during the daylight hours, and then move to the front yard patio after dark.

So I would like to build a carousel base for the drum kit with wheels under it so it can be rotated instead of having to deal with trying to turn the entire kit around piece-by-piece. It doesn't really need to be motorized. But hey, why not? The drummer can just push a button and turn the whole shebang around without even having to get off the stool.

So many projects. Will I live long enough to complete them all?

 

[Robo_Pi]

From a surface grinder to a drum merry-go-round. That's my life's story. Don't mind me, I have ADHD.