3 Phase Bandsaw Questions

[Sven Berg]

Hi everyone, I just joined the forum. I've done some searching on this topic, but I'm also looking for some advise.

I just bought a used Laguna LT16 HD bandsaw. This machine has a 5HP Baldor 3 Phase motor on it. I only have single phase power in my shop. Machine was a good deal even if I have to replace the motor. I've been reading up on VFD's (I've never used one), and phase converters. It seems like the cheapest solution would be to pick up a single phase motor. VFD's above 3 HP with single phase input and 3 phase output seem rare/expensive.

I do kind like the idea of putting a VFD on this saw. The benefit of adjustable speed could be handy. I did find one VFD that supposedly matches my spec for about $300. Not sure if I should be warry of a Chinese brand unit?

So best option? Swap motor or large VFD or something else I'm not considering?

[Bradley Gray]

You should also consider a rotary phase converter, home made or commercial. If you happen to have an extra 5hp 3phase motor this can be very cheap to set up.

A converter allows you to keep the starter switch on your band saw and also to buy more 3phase equipment!

[Bruce Wrenn]

Because this is your only 3 phase equipment, and if it's 220, why not convert motor to be its own phase convertor? Look in Workshops forum for and example of 3 phase rotary convertor. Practical Machinest web site has tons of info on building 3 phase rotaries.

[Darcy Warner]

I would add a vfd. There are generic ones out there rated for 5hp single phase in.

[andy bessette]

Find a good, used, single phase, 2-3 hp motor.

[Peter Christensen]

Get a VFD. Powtran make good ones, yes they are Chinese and you can get one for less than $300 to your door. Compare it to a single phase 5hp replacement motor and you’ll go for the VFD. Want some other pluses for the VFD besides speed control. Soft start draws fewer amps at startup and you can set it up with blade braking if you prefer to have it stop over several seconds instead of spinning for a while. I’d do it if my bandsaw was a 3 phase.

[joseph mansker]

I think the best advice I can give you is make sure that you can get some assistance from the tech support staff from the manufacturer of the vfd if you go that route. I just completed my first three phase conversion with a vfd on a 1 hp grinder and it went pretty easy until I tried to start the grinder. Thank goodness for the tech support staff at TECO Westinghouse!...had my grinder up and running five minutes after I had them on the phone. I posted some information on the conversion here on this forum. Good luck!
Joe

[Bill Dufour]

You can run it on a 3hp vfd and it will be fine.. but it will only be a 3hp motor. How much do you really need the extra 2 hp? If it matters that much go ahead and buy the bigger vfd. Be aware the longer you wait the cheaper the 5hp units will become.
You can not slow down the motor very much as you lose torque inverse to rpm drop. FYI:you need about 20 to 1 reduction to cut metal on a bandsaw.
Bill D

[Sven Berg]

Ok lots of good thoughts. Thanks for the input. I'm leaning towards a VFD. I can get one shipped to me for a little under 300. I'll do a little digging on the machinist forum about the phase converter option. I'll update whichever way I go and show the final results!

[Kevin Beitz]

Making a phase converter is easy...

[Curtis Horswill]

If you plan on adding more 3 phase equipment in the future a rotary phase converter is a good option. If you plan on going the VFD route I would check with Jack Forsberg. He sells VFDs that are rated for single phase input. When I inquired about a 5 hp VFD I believe the price was less than $300. I also believe that he will pre program the VFD if you provide the motor specs.

[Jeff Duncan]

Usually bandsaws are very easy motor swaps, making a motor swap likely the least expensive and possibly most practical solution. VFD's are good for machines that are hard to convert due to specialized motors, or machines that benefit from adjustable speed. Bandsaws do not generally fall under either category. Lastly VFD's are not a perfect solution for converting from 3 to single phase, but are one relatively inexpensive compromise to accomplish it. Rotary phase convertors of course can get you there too. Then again it's a whole lot of extra "stuff" added in order to run your bandsaw. In this situation.... a good replacement motor and new switch is simpler, likely cheaper, (especially if you find a used one), and closer to foolproof.... IMHO.

good luck,
JeffD

[Dave Cav]

I'm running seven VFDs in my shop, mostly TECO. I'm using VFDs rather than an RPC because I don't want to deal with a separate 3 phase distribution system, and I acquired my equipment incrementally. I've been running a 5 HP Delta 12/14 table saw on a 3 HP TECO vfd for nearly 10 years now with no problems, and I've only tripped it out on overcurrent three or four times. TECO has excellent customer support via Factorymation should you need it, but they're generally pretty easy to hook up.

[andy bessette]

JD--good post.

OP--if you replace the motor you can resell the old one to offset the cost of the new one. That is the simplest and cheapest way to do it. Or you could keep the old 3-phase motor from which to build a rotary phase converter.

[Sven Berg]

So if I'm searching for a replacement motor, is the frame code a universal number or brand specific? This baldor has a frame code of 184TC, with an rpm of 3450.

[andy bessette]

A motor of the same frame code will simplify installation. Stay with the 3450 RPM.
http://www.castellanomotors.com/motors/mtrdia/nema/flanged/fr184tc.htm

[jack forsberg]

I'm running seven VFDs in my shop, mostly TECO. I'm using VFDs rather than an RPC because I don't want to deal with a separate 3 phase distribution system, and I acquired my equipment incrementally. I've been running a 5 HP Delta 12/14 table saw on a 3 HP TECO vfd for nearly 10 years now with no problems, and I've only tripped it out on overcurrent three or four times. TECO has excellent customer support via Factorymation should you need it, but they're generally pretty easy to hook up.
At some point Dave I’d like you to talk you into a fully developed drive. We’re talking peanuts here. I don’t remember how long ago I started to hear about the FM 50 being discontinued but it’s going to be going on five years.!

[jack forsberg]

I'm running seven VFDs in my shop, mostly TECO. I'm using VFDs rather than an RPC because I don't want to deal with a separate 3 phase distribution system, and I acquired my equipment incrementally. I've been running a 5 HP Delta 12/14 table saw on a 3 HP TECO vfd for nearly 10 years now with no problems, and I've only tripped it out on overcurrent three or four times. TECO has excellent customer support via Factorymation should you need it, but they're generally pretty easy to hook up.
At some point Dave I’d like to talk you into a fully developed drive. We’re talking peanuts here. I don’t remember how long ago I started to hear about the FM 50 being discontinued but it’s going to be going on five years.! What is in particularly a huge advancement is the three stage field which allows components to be changed should there be a problem. Most VFD manufactures do not walk newbies through technical problems but with the new VFD builds it is very simple. So easy to do a monkey could do it. A faulty door shorted out system is simply a component away . This is Service beyond warrantee .

[Sven Berg]

A motor of the same frame code will simplify installation. Stay with the 3450 RPM.
http://www.castellanomotors.com/motors/mtrdia/nema/flanged/fr184tc.htm

Nice graph. Thanks!

[Dave Cav]

At some point Dave I’d like to talk you into a fully developed drive. We’re talking peanuts here. I don’t remember how long ago I started to hear about the FM 50 being discontinued but it’s going to be going on five years.! What is in particularly a huge advancement is the three stage field which allows components to be changed should there be a problem. Most VFD manufactures do not walk newbies through technical problems but with the new VFD builds it is very simple. So easy to do a monkey could do it. A faulty door shorted out system is simply a component away . This is Service beyond warrantee .

If I need to replace one of my existing drives, or get a new 3 phase machine I'll be in touch as I have wanted to try one of your drives out for some time. However, my TECO drives have been very reliable, and I'm at the point where I'm actively NOT looking for any new old machines to restore. Or if (when?) the relatively cheap WEG 5 HP single phase motor on my compressor craps out.