Do all that don’t do ****

[Flyin Flattie]

Ok so I got this awesome machine a few months back and I decided to get a VFD for it to try and get it going since I don’t have 3 phase power in the shop. I plan on eliminating the variable belt speed and simply using the vfd to change speed and do a direct drive from the motor to the transfer case . My question is is this the right motor for this machine?

The plate on in the top cover says 3,550 for variable transmission and motor to variable says 3330 and my motor says 1750 rpm. I feel like a different 3 phase motor with a 3,600 and up rpm range is needed to meet what it says it needs.

The vfd works and the motor seems to be running full speed but it was slow and something would keep popping like it had an internal clutch in the case that transfers the power from belt to band saw blade.

I tryed different size pullies from what came on the motor ( small) to a 4.5 then a 7” and it seemed to help gain proper speed but the damn clutch thing kept popping as soon as I start to make traction on a cut.

Please any adobe would help the VFD is rated for a 3 hp 3 phase motor and has 220 single phase going into it so I can change to a different motor. I just need a simple answer as to why it ain’t working.

Thank you Tim

 

[r_olson_06]

Hey Tim,
When using a VFD to convert single phase to 3 phase the VFD needs to be rated at 2X the amperage of the motor. So if your motor is rated at 6A @ 220V you need a 12A drive unless the VFD is specifically rated to do the single phase in.

Also if you use the VFD as the transmission to adjust speed please consider that you will have no mechanical advantage gains like you did with the mechanical drive. So if you run the motor at 1/2 speed you will have 1/2 the output power.

Let me know if you have any questions but I would check sizing of the VFD first and then check wiring. Upload a picture of the wiring if you could on both the VFD and motor connections.

Looking for a Plomb 3061 Pebble Open End.

 

[Model A Fan]

I spy a Model A cowl. I saw one of these for sale locally but the 3-Phase makes me nervous as I am not set up for such machines. Good luck, I wish I could add more. Looks like a great saw that has some cool styling.

https://bellingham.craigslist.org/tls/d/bellingham-doall-bandsaw/7120130480.html

 

[Lightning rod]

Don’t know if you have a operating or parts manual , but you find them here
http://vintagemachinery.org/mfgIndex/detail.aspx?id=257&tab=3
Maybe what you are describing is mechanical ?

 

[Flyin Flattie]

Hey Tim,
When using a VFD to convert single phase to 3 phase the VFD needs to be rated at 2X the amperage of the motor. So if your motor is rated at 6A @ 220V you need a 12A drive unless the VFD is specifically rated to do the single phase in.

Also if you use the VFD as the transmission to adjust speed please consider that you will have no mechanical advantage gains like you did with the mechanical drive. So if you run the motor at 1/2 speed you will have 1/2 the output power.

Let me know if you have any questions but I would check sizing of the VFD first and then check wiring. Upload a picture of the wiring if you could on both the VFD and motor connections.

Looking for a Plomb 3061 Pebble Open End.

Here’s the VFD I got. I hope it works for my application.

Off the top of anyone’s head do they know the belt lengths I need with the stock small pullie.



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[dutchgray]

The clutch as you describe is actually a clutch on a two speed transmission that you are supposed to change gear when it is running at the slowest speed on the variable speed belt drive. I would investigate this to find out why it is jumping out of gear.
I would not remove the variable speed pulley system if it is working, you will lose torque at the slower speeds if just using the VFD to alter the speeds and its at the slow end where you need the most torque. I you keep the variable belts you can use either to alter the speed as needs arise.

 

[Flyin Flattie]

The clutch as you describe is actually a clutch on a two speed transmission that you are supposed to change gear when it is running at the slowest speed on the variable speed belt drive. I would investigate this to find out why it is jumping out of gear.
I would not remove the variable speed pulley system if it is working, you will lose torque at the slower speeds if just using the VFD to alter the speeds and its at the slow end where you need the most torque. I you keep the variable belts you can use either to alter the speed as needs arise.

For sure that’s the plan after debunking my stupid idea. I guess I’ll have to crack open the transmission and give it a once over


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[whateg01]

You can measure the belt length by wrapping a rope around the pulleys if the manual linked above doesn't have that info.

Dave

 

[Kev442]

This is one of my favorite thread titles on GJ of all time.

 

[Zeeman]

Is it OK to say **** on GJ? What kind of stuff is it supposed to do? I'm not familiar with that machine.

 

[whateg01]

Is it OK to say **** on GJ? What kind of stuff is it supposed to do? I'm not familiar with that machine.

It's a bandsaw.

Dave

 

[Zeeman]

Oh, I thought it might mill also, or do a lot of other stuff.

 

[gorilla]

It's a bandsaw.

Dave

It's a really really good bandsaw.

 

[whateg01]

Oh, I thought it might mill also, or do a lot of other stuff.

That would be the Shop Smith in woodworking. Does it all, but not very well!

Dave

 

[Doug Arthurs]

Awesome saw. I use mine all the time. Mine was converted to 120v before I got it. They just swapped out the motor. I had to rewire it as the wiring was poorly done. Put a couple new belts on and it works great. Not sure why with the 2 speed variable speed set up you would need to add a VFD. Also I removed the welder and the air pump that use to blow air on your part. Both were not working.

 

[Flyin Flattie]

Awesome saw. I use mine all the time. Mine was converted to 120v before I got it. They just swapped out the motor. I had to rewire it as the wiring was poorly done. Put a couple new belts on and it works great. Not sure why with the 2 speed variable speed set up you would need to add a VFD. Also I removed the welder and the air pump that use to blow air on your part. Both were not working.

The VFD was to get the 3 phase motor that was on it going. What RPM is your motor you have now


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[Flyin Flattie]

Excuse my dingusness but it says 3330 for motor to variable speed. Does that mean I need a motor that runs at 3330 rpm because mines 1750


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[tool_scrounge]

Excuse my dingusness but it says 3330 for motor to variable speed. Does that mean I need a motor that runs at 3330 rpm because mines 1750


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That looks like the Gates V belt number

 

[Flyin Flattie]

Hey so what should the motor rpm be because it says motor to variable 3330 so I imagine that means I need a motor that runs around 3330 rpm. The motor in it now is a 1750.


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[ClappedOutBport]

It confuses the hell out of me when people buy high end bandsaws designed by excellent engineers just to throw that all away for some power-losing electronics. Perhaps before destroying one of the best rated saws of all time maybe figure it out a little bit first. The gearing on that saw from the factory was likely perfect for 99% percent of users. The variable speed reeve's drive worked excellently and in combination with the two speed gear box gave you almost every speed you'd ever need.


My recommendation:

• Stop ditching Doall's hard work and understand the drivetrain. Investigate why it's popping out of low gear and fix it. Put it in high gear since you clearly want to run fast (I hope you aren't cutting steel at those speeds!)
• Put the stock pulley back on. It was meant to be unless you only ever wish to cut wood. This is the wrong bandsaw for wood anyway.
• Leave the variable speed drivetrain alone. It doesn't hurt you. If you want to use VFD speed control, set the variable at the max. If you rip it out and someday find yourself wanting full power at low speed, you'll be kicking yourself.

 

[ClappedOutBport]

I spy a Model A cowl. I saw one of these for sale locally but the 3-Phase makes me nervous as I am not set up for such machines. Good luck, I wish I could add more. Looks like a great saw that has some cool styling.

https://bellingham.craigslist.org/tls/d/bellingham-doall-bandsaw/7120130480.html

Life is too short to be afraid of three phase! You'll miss out on all the best machines and the nicest running motors you'll ever find. Once you get used to three phase you'll never want to see another motor with a capacitor attached again.

Hey so what should the motor rpm be because it says motor to variable 3330 so I imagine that means I need a motor that runs around 3330 rpm. The motor in it now is a 1750.


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Perhaps try reading tool_scrounge's post before asking the same question again. 3330 RPM motors don't exist on 60 hertz, or if they do, they're rated for much more slip than usual. All 2 pole 60hz motors have a synchronous speed of 3600 RPM and most have a full load speed for 3450 RPM. Most every metal-working machine tool I've seen has a 4 pole (1750 RPM) or slower motor.



I am sure that if you read the literature on vintagemachinery.org or elsewhere instead of hack-and-slash mechanic-ing, you would save yourself a lot of headache.

 

[cvairwerks]

That data plate lists Gates belt numbers and not any kind of speed information.

 

[Farmer J.]

Life is too short to be afraid of three phase! You'll miss out on all the best machines and the nicest running motors you'll ever find. Once you get used to three phase you'll never want to see another motor with a capacitor attached again.

Three phase is the best, as well as powering everything on the farm I even have a 440volt 3 phase into our house...
One of the best tricks is to split the phases and run 3 different 240volt single phase things at the same time for the cost of one!

 

[Provincial]

Phase splitting is pretty much limited to commercial power in the USA. All residential power is "1 phase", meaning two legs that produce 240 volts when used together, and 120 volts one leg to "neutral", which completes the circuit back to the generator through ground.

The down side of 3 phase is that if you unbalance the load, you are charged based on the leg with the highest draw!

 

[930dreamer]

I'd like a find a nice DoAll someday.

 

[Flyin Flattie]

It confuses the hell out of me when people buy high end bandsaws designed by excellent engineers just to throw that all away for some power-losing electronics. Perhaps before destroying one of the best rated saws of all time maybe figure it out a little bit first. The gearing on that saw from the factory was likely perfect for 99% percent of users. The variable speed reeve's drive worked excellently and in combination with the two speed gear box gave you almost every speed you'd ever need.


My recommendation:

• Stop ditching Doall's hard work and understand the drivetrain. Investigate why it's popping out of low gear and fix it. Put it in high gear since you clearly want to run fast (I hope you aren't cutting steel at those speeds!)
• Put the stock pulley back on. It was meant to be unless you only ever wish to cut wood. This is the wrong bandsaw for wood anyway.
• Leave the variable speed drivetrain alone. It doesn't hurt you. If you want to use VFD speed control, set the variable at the max. If you rip it out and someday find yourself wanting full power at low speed, you'll be kicking yourself.

My dude I clearly have understood that my theory was wrong a long time ago and am looking for a simple straight forward answer rather than back handed smart assery. I appreciate the advice and am putting it back to stock. I guess my next move is to rebuild the transmission since that obviously is popping out of gear.


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[Flyin Flattie]

Im very excited about 3 phase and am looking forward to all of my machines I have that are 3 phase humming along without problems. I’d just like for the stuff to work so I can get back to work building other things than machines that help me build other machines lol.


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[dutchgray]

We are somewhat lucky in the UK in that any domestic single phase supply is any phase from the 3 phase to neutral, but having 3 phase it self is very rare in a domestic situation, industrial buildings mostly will have 3 phase and a lot of farms as well. Its is also in general more expensive to have it.
So if you have 3 phase you can split out a standard single phase 240v very easily, or even pull from 2 phases at a higher voltage to reduce current draw and cable sizes for welders etc.
My little workshop has 3 phase fed from the 1MW transformer on the industrial site, the owner of which had to pay for and all the underground cabling, the utility also doesn't dig on your property, even though its for their cables that you have paid for but never own, thats up to you to sort yourself, you also have to pay for the job in full before they will do it, then they usually take months to get to it.
3 phase is nice to have though if you can get it

 

[ClappedOutBport]

My dude I clearly have understood that my theory was wrong a long time ago and am looking for a simple straight forward answer rather than back handed smart assery. I appreciate the advice and am putting it back to stock. I guess my next move is to rebuild the transmission since that obviously is popping out of gear.


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Hey sorry about that. I'm human, I get frustrated, I see this a lot and this is the thread I vented my frustration in. My apologies. Lets put it behind us eh?


Sounds like you're on the right track now, let us know how it goes in the gearbox.