I need to replace an old motor with a more powerful one. The current one is probably from the 1950-70's and is rated at 1/4hp constant duty. I have a 2hp motor that I would like to use b/c I have it and having more power would be very useful for the saw as the 1/4 is WOEFULLY underpowered. The thing is that I'm not good with reading motor labels and understanding the different terms to determine if this motor will work for what I'm doing which is cutting thick pieces of oak (3-6" thick) and also aluminum up to 1.5" thick (different blades for each).

The current motor runs on 120 and I can run 240 to it, but I know it takes some equipment to emulate 3 phase from normal electricity. IDK if there are any other options or if there is any new hardware/equipment that allows to use 3 phase motors, something like a PWM or some DC drive controller.

Here are the pics of what is currently on the saw and the motor I have to replace it.

 

Something like this...
https://www.ebay.com.au/itm/2-2KW-3...411382&hash=item544e88da7d:g:~1oAAOSwOtVaub4H

 

The Chinese origin VFD's as shown in the Ebay link are fairly cheap, but beware their manuals leave a lot to be desired and virtually no support.
But one would run that motor from 1ph 240v.
Max.

 

Thanks for the links! I have seen something like this but they are domestic and about $800-$2,000 new (I think, it may depend on size), but I've seen them at surplus/liquidation auctions for VERY good prices from $20-100 each and even lots of 12 sold for under $500 (and each was valued at $1200 new). I didn't know what they really did at the time and wasn't sure that the $1200 was a legitimate price. I'll have to keep my eyes open for one of these at the surplus store/auction.

 

Many of the older high end VFD's were not set up for 1ph input, you need to be aware of this when shopping around, usually the limit for 1ph in is 5hp rated also.
Max.

 

There is also the possibility that putting a 2HP motor on something made to use 1/4HP is not a good idea. From a parts breakage point of view. Can it be done, yes, the big question is should it be done. There was a reason it came from a factory with 1/4HP instead of 2HP.

 

There is also the possibility that putting a 2HP motor on something made to use 1/4HP is not a good idea. From a parts breakage point of view. Can it be done, yes, the big question is should it be done. There was a reason it came from a factory with 1/4HP instead of 2HP.

That was my first thought when I read the original question, but I have exactly zero experience servicing or modifying power tools, and 99% of the power tools I've used were reasonably modern, so I didn't know if things might be different with an older piece.

My gut feeling still says don't overpower a potentially dangerous tool, certainly not by a factor of 8!

 

The place to look for a VSD is "Automation Direct" because they provide excellent support and they are fairly cheap. And they do have the smaller sizes of drives for things like this, including units made to run on single phase.
BUT will this motor even fit on the saw?
My suggestion is change to a sharp carbide blade and the 1/4 HP motor will do a much better jub.

 

I've set up a fair number of phase converter systems both rotary and vfd and they work fine provided you keep a few thngs in mind. First forget about the el-cheapo 'static phase converters' you lose 1/3 horsepower woth these and they do not do well in high torque situations. Second, the amp load on the single phase supply could be quite high and may need upgrading. Third, and quite important , you must be sure not to use the 'manufactured' third leg for any control circuits. Lastly, the vfd must connect directly to the motor, no switches contactors in between or you can fry the vfd - the vfd becomes the switch and you control it.

The best way to do this is a rotary unit with a 3-phase vfd after it. But that isn't cheap. I like the vfd for the soft start and variable speed ability. The vfds with single to three phase direct ability work fine but can get expensive above 5hp. The variable speed would be very nice if you intend to cut aluminum as it should be at much slower surface speed. Really the aluminum would be better cut on a bandsaw.

Overall it would be cheaper easier to buy a proper single phase saw motor.

The question is should you put that much power on that saw? We don't know what saw you have but my 1950's Tannewitz will eat 6" oak but - it weighs around 3000 lbs, has 18" blades and 7.5hp.

Good luck.

 

Lastly, the vfd must connect directly to the motor, no switches contactors in between or you can fry the vfd - the vfd becomes the switch and you control it.

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I agree there is no need to switch the output when using a single motor, however I have used one application where two identical motors were used and a contactor set up to switch between each, a digital output of the VFD was used to interlock the contactor switching to ensure the VFD was at zero output when this occurred.
Max.