DoAll Bandsaw for Brian

[jkimberln]

I think the blade welder current is generated at fairly low voltage through a transformer. Unless that transformer is wound for three phase and says so, it probably runs off single phase. But even if it does run off three phase, I wouldn't want to run it off a VFD. A rotary converter would probably be OK. As far as I know, the output of a VFD should never be switched on or off while the input is hot.

 

[Chiptosser]

Why would you want a VFD for this saw??
I has a manual variable speed .
Most of the Doall welders are 200-240v

 

[jkimberln]

You would want a VFD if you didn't have 3 phase in your shop and the machine motor was three phase. The VFD is the cheapest way to achieve 3 phase from single phase. So you set the manual variable speed at max and use the the logic circuit in the VFD to turn the machine on and off and vary the speed.

 

[Chiptosser]

You can think of it that way. In that situation the motor is put under the highest starting load. That defeats the mechanical advantage of starting at a lower speed with the variable speed pulleys. For single use motors, a Phazpak unit is cheaper than a VFD.
Two wires to connect.

 

[L98fiero]

You can think of it that way. In that situation the motor is put under the highest starting load. That defeats the mechanical advantage of starting at a lower speed with the variable speed pulleys. For single use motors, a Phazpak unit is cheaper than a VFD.
Two wires to connect.

Hard to tell from their website but aren't the Phazpak units just start capacitors? If that's the case, while that would probably be fine for home use, the driven motor will only produce about 2/3 of the stated horsepower,

 

[trlvn]

Hard to tell from their website but aren't the Phazpak units just start capacitors? If that's the case, while that would probably be fine for home use, the driven motor will only produce about 2/3 of the stated horsepower,

You are exactly right. If you search for "static phase converter", there are several suppliers of such equipment. The description from North American Phase Converters website, as an example, says:

A static phase converter is used to generate 3 phase power during the starting of a motor. A static phase converter consists of one or more start capacitors and a start relay. The start capacitors produce electricity across the third winding of a motor during start up, once the motor is up to speed these capacitors are disconnected from the motor winding. The motor load is now running on just the two single phase lines of power (in essence, the motor is single phasing). There is at least a 1/3 power loss of the motor horsepower.

Designed for: Light and medium starting and running motors.

https://www.northamericaphaseconverters.com/phase-converters/static-phase-converters/
McMaster-Carr offers a variety of units. USD 196.55 for a 1-3 horsepower unit, for instance.

https://www.mcmaster.com/static-phase-converters/
For a rough comparison, McMaster wants USD 683.86 for a 2HP VFD
https://www.mcmaster.com/7786K55/
Craig

 

[OrangeAlpine]

I have two Ebay VFD's and find them to be a great value. Easy to install and work remarkably well. The preset values work and the soft starts are terrific.

Bill

 

[trlvn]

BTW, on another forum that I follow, a fellow has been restoring and adding a VFD to a DoAll bandsaw. Albeit is somewhat larger model:

https://www.owwm.org/viewtopic.php?f=77&t=226012
Craig

 

[Peter Murphy]

Nice Purchase Brian. If you lookup Steve Summers he recently did a series of videos on restoring a DoAll Band saw like yours. He did make up some new guides.
Cheers Peter from Oz

 

[awake]

You would want a VFD if you didn't have 3 phase in your shop and the machine motor was three phase. The VFD is the cheapest way to achieve 3 phase from single phase. So you set the manual variable speed at max and use the the logic circuit in the VFD to turn the machine on and off and vary the speed.

Cheapest? Maybe not. I put together a rotary phase converter to run my 2hp Bridgeport for a total cost of around $40 - and most of that was for the twist-lock plug and receptacle!

Of course, to do something for that sort of price, one has to have a free or nearly free 3-phase motor of suitable size on hand. I picked up a 3hp 3-phase motor out of the scrap bin; it had been scrapped because the front bell housing was cracked and split. I used a couple of clamps to hold it together and tested the motor - the bearings were a bit noisy, but overall it ran fine. So I tig-brazed the bell housing back together, and have been using it for many years now as the heart of my RPC.

One could stop there, just using a spare motor and starting it using a rope - but of course I wanted more convenience. I talked with a neighbor who does HVAC work and was granted unlimited access to his scrap pile, full of transformers and contactors and capacitors - I was able to get everything I needed to put together a starting circuit and balancing capacitors, and the only thing I had to add was a couple of push-button momentary switches (a few dollars from Amazon) and, as mentioned, the twist-lock plug and receptacle (maybe $25? $30? something like that).

I built an enclosure out of scrap plywood, and voila - my RPC has been working flawlessly for many years now.

 

[JLaning427]

I don’t know about your part of the world, but in the US, a VFD is a reasonably cheap way to run a 3 phase motor on Single phase. A VFD capable of 3hp is available on Amazon for $88. I have one running a 3hp KV24 bandsaw. You get soft starts and the ability to vary speed with the touch of a button. I have a switch set up to hit 60hz and 30hz (half speed). If I need slower or faster I crank the mech variable speed up or down. Or change ranges low range for ferous metals, high range for wood and non-ferous metals. And yes, it probably cost more than a junk 3ph idler motor and some capacitors, but it was pretty close to plug and play.

James

 

[Brian Rupnow]

After almost a full days work, the bandsaw is in its home position. Far more work there than simply unloading it from my truck. It's amazing what one old man with a lot of rope, a garden tractor, and a rockbar stolen from the Faraday uranium mines 50 years ago can accomplish. In the pictures you will see some of the remaining garage sale stuff that has yet to go. My wife has told me that I can have one bay of the garage for my equipment, but By God she wants a full bay left for her Honda in the wintertime.----Yes Dear!!!---. This saw has a really nice guide or fence on the tabletop. I'm sure that will come in very handy. My VFD came today, and after a very quick look I decided that it was out of my league, so I called a friend who is an electrical guy and he is going to come over and wire it for me.

 

[stragenmitsuko]

VFD's are defintly the way to go .
The softstart , the slope down , the breaking options; not to mention the rpm controll .... unbeatable .
I have 3 phase in my shop , we even have 3*380V in europe and still I rewired most of
my machines to use a a 3phase in - 3 phase out vfd .

Very nice bandsaw

Pat

 

[IC-man]

After almost a full days work, the bandsaw is in its home position. Far more work there than simply unloading it from my truck. It's amazing what one old man with a lot of rope, a garden tractor, and a rockbar stolen from the Faraday uranium mines 50 years ago can accomplish. In the pictures you will see some of the remaining garage sale stuff that has yet to go. My wife has told me that I can have one bay of the garage for my equipment, but By God she wants a full bay left for her Honda in the wintertime.----Yes Dear!!!---. This saw has a really nice guide or fence on the tabletop. I'm sure that will come in very handy. My VFD came today, and after a very quick look I decided that it was out of my league, so I called a friend who is an electrical guy and he is going to come over and wire it for me.

 

[IC-man]

My dad used to say "give me a fulcrum point and a long enough lever and i will move the earth.

 

[ajoeiam]

My dad used to say "give me a fulcrum point and a long enough lever and i will move the earth.

Hmmmmmmmmmmm - - - dad was quoting Archimedes . . .

 

[Gordon]

After almost a full days work, the bandsaw is in its home position. Far more work there than simply unloading it from my truck. It's amazing what one old man with a lot of rope, a garden tractor, and a rockbar stolen from the Faraday uranium mines 50 years ago can accomplish. In the pictures you will see some of the remaining garage sale stuff that has yet to go. My wife has told me that I can have one bay of the garage for my equipment, but By God she wants a full bay left for her Honda in the wintertime.----Yes Dear!!!---. This saw has a really nice guide or fence on the tabletop. I'm sure that will come in very handy. My VFD came today, and after a very quick look I decided that it was out of my league, so I called a friend who is an electrical guy and he is going to come over and wire it for me.

Do you have 220 volt at that location? I would have thought that placing where the old saw is located would have put it near the 220 volt used by the welder.

 

[Brian Rupnow]

I can't put the new saw on that side of the garage because it is too big, and would stick out into the area my wife needs to park her car in during the winter.

 

[comstock-friend]

First question---The new saw has wheels 1.010" wide x 16" diameter, and the blade on it was 1/2" wide. Can I safely run 3/4" wide blades on it. I don't cut curves, and the 3/4" wide blades are what I have always ran on my smaller converted wood cutting bandsaw.

The chart on the front lists all the blade widths, materials, and speeds and feeds. And if like the bigger DoAll's, the guides for the other blade widths are in a rack inside the blade cover. But you know all this by now I hope.

 

[Brian Rupnow]

Comestock Friend---I just ran out to the garage and looked, but no luck!!! No blade guides in there.---Brian