Need information on 3 phase

[John Bailey]

I'm looking into buying an Oliver 192 band saw that has a direct drive 3 phase motor. I've got a small shop, 20x20, and no 3 phase power. I'm thinking of buying a 3hp rotary phase converter to run this saw. Any ideas, or suggestion, on the wisdom of this plan would be greatly appreciated. I don't know anything about 3 phase power, but I think it could be a good thing in a shop that is getting filled with vintage machines.

Thanks, John

[Dennis Ford]

If you rig up the phase converter so that its output can be used on more than one machine (one at a time) this will be an economical solution. If the phase converter is dedicated to one machine, a variable frequency drive would be a good choice.

[John Bailey]

If you rig up the phase converter so that its output can be used on more than one machine (one at a time) this will be an economical solution. If the phase converter is dedicated to one machine, a variable frequency drive would be a good choice.

Thanks Dennis,

I've been reading about phase converters, but I haven't come across variable frequency drive. Could you direct me to a website that could fill me in.

John

[Eric Larsen]

If you can live with 1/3 less HP, the Phase-A-Matic static converter is inexpensive, easy to install, basically foolproof. I have one on my 5hp motor on my PM66. Works very well.

Three-phase electric service is prohibitively expensive for most residential customers. Rotary converters are also expensive, especially if only powering one or two machines.

My first choice, though, would be to swap out the motor with a single phase Baldor.


I'm looking into buying an Oliver 192 band saw that has a direct drive 3 phase motor. I've got a small shop, 20x20, and no 3 phase power. I'm thinking of buying a 3hp rotary phase converter to run this saw. Any ideas, or suggestion, on the wisdom of this plan would be greatly appreciated. I don't know anything about 3 phase power, but I think it could be a good thing in a shop that is getting filled with vintage machines.

Thanks, John

[Rick Christopherson]

John, you have a couple of options depending on the size of the motor. A quick search on the internet and I found one 192 bandsaw that had a 2 hp motor. This is a little small for that size frame, so if yours is only 2 hp, then I don't think I would use a static converter. If yours is 3 hp or above, then a static converter would work. The basis of where I am going with this is how close to full-load you will be operating the motor. If you don't need to get full load from the motor, then a static converter is an economical solution. If you modify a store-bought static converter and make it a balanced static converter, then you will get nearly as good performance as you would from a rotary converter.

On the other hand, if the motor is less than 3 hp, then the VFD is flat-out the best choice for performance, convenience, and cost. In simple terms, a VFD is a computer controlled phase converter, and these smaller sized units are very inexpensive. The Teco FM50 line is the cheapest, but I prefer the GS1 or GS2 for functionality. For a bandsaw, you don't really need much functionality, so an FM50 is fine.

For larger motors, the most economical solution is to build your own rotary converter. If you can't build your own, or can't find one used for a good price, then even the larger VFDs are possibly more economical. The drawback to a rotary converter is that it must be running before the tool runs, so it is less convenient for being able to walk up to the machine and make a quick cut. For VFDs above 3 hp, you need to derate them in order to connect them to single-phase input power. In order to get 5 hp from a VFD powered by 240-volts single-phase, you need a VFD rated for 7 hp.

[Joe Meazle]

If you plan to fill the shop with 3 phase I guess a RPC would be the way to g but you would need to get a big one to accomidate future expansion. Most planers I see run 7.5 hp. I put a VFD on my 3hp 3phase 24" band saw and love it. I got full power and torque plus varrible speed for less than $200. All useful on a bandsaw. It is easy to wire too. I got this one from Factorymation. BTW Russ, the tech guy, is very helpful. I added a braking resitor and a big saftey switch to mine. I can get the big CI wheels on mine stoped in under 3 seconds automaticly.


http://www.factorymation.com/s.nl/it.A/id.198/.f?category=32

[Alan DuBoff]

Bandsaws are one of the machines that take a big draw, and if you use a Rotary Phase Converter, you will need one that is rated at 1/3rd more HP. Or to think of it in better way, you can only start 2/3rds the rated HP for certain machines, like a band saw, it draws a lot as it kicks up to speed.

You should plan on a 5HP RPC if you go the RPC route.

If you go static you will only get 2/3rds the rated HP from the motor, so a 3HP motor will give you about 2HP when used on a static phase converter. That's not bad, 2HP is quite a bit for a band saw, IMO.

I use a 7 1/2 HP RPC, and my biggest machine is 5HP, which is my table saw, and it would probably start on a 5HP RPC.

Once you have 3 phase in your shop, it will open up other avenues for used machinery, since 3 phase equipment usually goes for pennies on the dollar.

[John Bailey]

Thanks guys,

By the way, I just made a deal on an Oliver 192 in Wisconsin. (see other post in GW) I don't know the horsepower yet, and it seems from your suggestions, that's going to have a lot to do with the determination of how to go about this.

I don't know yet, but if the motor is original, I've found most 192's had 1 or 1.5 horsepower. These are old horses that seem to be able to do heavier work. In the pictures, it would seem it's not the original, so I'll have to address that when I get the machine.

Again, thanks for the information.

John

[Steve Jenkins]

I have a lot of 3 phase machines and use a rpc to power them. I wired up a 3phase panel beside my single phase one and power the third leg with the phase converter. All my 3 phase machines are fed off this panel. It is somewhat of a hassle to have to turn on the converter prior to the machine but if you are working with different 3 phase machines all day just let the converter run.

[Jacob Szajkowski]

I am in the process of building a rotary phase converter using a 7.5 hp GE motor. I've been using a Phase-A-Matic static converter to power a planer and radial arm saw. Very easy to wire up (I am not an electrician), they have very good customer service too. I will post pictures as the process unfolds. I've got three - 3 phase 5 hp motors to power: planer, ras, cyclone blower motor. 7.5 is 50% larger than 5, so it should work.

[John Bailey]

I picked up the Oliver 192 today. The good news is, although it was set up for metal cutting, it has a 875 rpm motor and I did'nt have to take the motor off. Because it's direct drive, that puts it at just about perfect at a blade speed of 4,121 sfp. The bad news is it's only 1/2 hp. I've been researching these small motors with low rpm. It seems that the lower the rpm, the more torque. So, this motor may be adequate, at least for awhile.

I'm going to do some work on it before I use it. I'm going to get a VFD for using the 3 phase motor. Any suggestions would be appreciated now that we know the size of the motor.

[Tom Veatch]

... I've got three - 3 phase 5 hp motors to power: planer, ras, cyclone blower motor. 7.5 is 50% larger than 5, so it should work.

Don't see that anyone has questioned this, so maybe my concern is unfounded, but it seems like two out of the three listed applications might be running simultaneously. In that event, would the 7.5 be large enough?

[Joe Meazle]

John,
Check the Amp rating on the motor. If it is less than 2.4 amps Here is an option.http://www.factorymation.com/s.nl/it.A/id.195/.f?category=32

If it is more Here is the next bigger one.
http://www.factorymation.com/s.nl/it.A/id.197/.f?category=32

There are the same ones (but in a bigger size) I used on my bandsaw a 3hp 24" Centauro. So far it has been great. It was a little daunting at first but once you get into it it is no more difficult that wiring a mag starter. Then I wanted to add stuff. Things like an aux. switch I added this one http://www.grizzly.com/products/110-220V-Paddle-On-Off-Switch/H8243

and thev I added a breaking resistor that can stop the big CI of my saw in 3 seconds. My 3hp version wa $28 but a 1hp can be had for $14 and may not even be needed. If you want some pics of my BS w/VFD shoot me a PM.

[John Bailey]

Does it matter if the VFD is rated higher than the motor? There may come a time when I want to move to more hp. If I got a 2 hp VFD now, will it hurt to run the 1/2 hp motor with it and not have to buy another in the future?

John

[Joe Meazle]

John, I am no expert. If it were I would call Russ at factorymation. He was super helpful with my bandsaw and had been helping me with a phase conversion on 5hp PM66.
Good luck,
Joe

[Roy Wall]

Does it matter if the VFD is rated higher than the motor? There may come a time when I want to move to more hp. If I got a 2 hp VFD now, will it hurt to run the 1/2 hp motor with it and not have to buy another in the future?

John

NO - it does not really matter......you don't want total overkill though...


Joe is correct to call Russ at Factorymation...they are very good. I have a FM50 to drive a 3ph, 1hp motor......you can just plug the vfd into a standard 115v wall outlet. It's kind of amazing.

[Rick Christopherson]

Does it matter if the VFD is rated higher than the motor? There may come a time when I want to move to more hp. If I got a 2 hp VFD now, will it hurt to run the 1/2 hp motor with it and not have to buy another in the future?

JohnNo, it does not hurt either the motor nor the VFD. It would only hurt your pocketbook if you never used the larger capacity.

[Steve Rozmiarek]

John, even though your shop dosen't have 3 phase now, is it available in your area from your utility company? If you are going to the trouble of powering multiple three phase machines through a converter running through a panel or something, you may find that the hookup makes sense financially. I just asked my supplier the question, and I was suprised at the price being lower then expected.