Woodworking Talk banner

1 - 16 of 16 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter · #1 ·
I purchased a used Rockwell 8" jointer, model 37-315. It has a 3-phase motor. I did not realized that I could not easily run 3-phase electricity in my home workshop. I'm wondering now if it would be easier to buy a converter to run the 3-phase motor or swap-out the motor for a single phase. I'm not sure if this model was originally available with a single phase motor. Does anyone have any experience with this?
 

·
Registered
Joined
·
539 Posts
I purchased a used Rockwell 8" jointer, model 37-315. It has a 3-phase motor. I did not realized that I could not easily run 3-phase electricity in my home workshop. I'm wondering now if it would be easier to buy a converter to run the 3-phase motor or swap-out the motor for a single phase. I'm not sure if this model was originally available with a single phase motor. Does anyone have any experience with this?
The 37-315 is a very popular jointer made for years under the Rockwell and Delta name. I am almost positive it was available in both 3 phase and 110/220 single phase. You should not have an issue finding a motor for it.
 

·
Premium Member
Joined
·
5,170 Posts
As mentioned, you have 2 realistic options; swap the motor or add a VFD. There are a couple other options, like a rotary phase converter, but one of those would probably cost more than the machine which is why i said "realistic options".

A VFD will be easier to source and the wiring isnt difficult. Price for a 2hp unit will be in the $150-300 range, depending on the brand. Will work just fine for what you need

A replacement motor could be a challenge, depending on what type of motor the original is, your location, etc. If the machine uses a proprietary motor style, youd be limited to swapping it with the motor from the single-phase version of the machine. Finding that could be a challenge, and the price would be pretty random as well. If its a standard frame motor, you would be able to find a single-phase version in the same frame, but here again, price varies. You might find one on the back shelf of your local machine tool supplier for $20, or the only one available might be a new Baldor for $600

Of the two, the VFD would honestly be the better option. Easier to find and install, but not as potentially cheap
 

·
Registered
Joined
·
1,118 Posts
a jointer is probably the most basic tool to replace the motor on
fixed spindle with pulley and belt going to a fixed position motor with another pulley
i'd buy a 1hp motor for it and sell the 3 phase motor to pay for it
 

·
where's my table saw?
Joined
·
28,606 Posts
There's nothing easier than swapping the motor out on a jointer. If the bolt holes on the base of the new motor line up, that's about all that's needed. A different length belt might be necessary also if there's not enough slot length. The switch will be the next issue and a double pole 220 Volt will work. No need for a magnetic type in a one man shop. If the power drops and then comes back on while you're jointing you should have enough time and foresight to turn it OFF before it restarts.
There's no need for a varible frequency drive on a jointer which operates at a fixed RPM. Try to match the new motor RPMs with the same as the original and then you can keep the pulley diameters the same. If not, there are great "on line pulley" calculators. I've done a lot of motor swaps over the years, so I'm not too intimidated by them.
I wouldn't use any motor less than 2 HP, preferrably a 3 HP. My 8" Grizzly had a 2 HP, and seemed fine however. My 13" jointer/planer has a 3 HP for the extra width.
New "take off" motors are available on Ebay:

Good price on this new one:
 

·
Registered
Joined
·
4 Posts
Discussion Starter · #7 ·
As mentioned, you have 2 realistic options; swap the motor or add a VFD. There are a couple other options, like a rotary phase converter, but one of those would probably cost more than the machine which is why i said "realistic options".

A VFD will be easier to source and the wiring isnt difficult. Price for a 2hp unit will be in the $150-300 range, depending on the brand. Will work just fine for what you need

A replacement motor could be a challenge, depending on what type of motor the original is, your location, etc. If the machine uses a proprietary motor style, youd be limited to swapping it with the motor from the single-phase version of the machine. Finding that could be a challenge, and the price would be pretty random as well. If its a standard frame motor, you would be able to find a single-phase version in the same frame, but here again, price varies. You might find one on the back shelf of your local machine tool supplier for $20, or the only one available might be a new Baldor for $600

Of the two, the VFD would honestly be the better option. Easier to find and install, but not as potentially cheap
Thank you for the response! I've been looking for a single phase motor to swap out, but am not finding a perfect match. The 3-phase motor that came with it is a "Frame 66, Type P". One of the sites I saw had a bunch of new motors that were 56 frames, but no 66. I was thinking I could add a board or something to mount the frame. Other similar motors have a 0.625 shaft, but mine is a 0.75.

I'm concerned about getting the correct VFD. I've heard it's best to oversize the converter. My motor is a 1hp, but I was thinking of going up to a 3hp VFD to have more available power and also in case I ever pick up another shop tool running 3hp 3-phase.
 

·
Registered
Joined
·
4 Posts
Discussion Starter · #8 ·
There's nothing easier than swapping the motor out on a jointer. If the bolt holes on the base of the new motor line up, that's about all that's needed. A different length belt might be necessary also if there's not enough slot length. The switch will be the next issue and a double pole 220 Volt will work. No need for a magnetic type in a one man shop. If the power drops and then comes back on while you're jointing you should have enough time and foresight to turn it OFF before it restarts.
There's no need for a varible frequency drive on a jointer which operates at a fixed RPM. Try to match the new motor RPMs with the same as the original and then you can keep the pulley diameters the same. If not, there are great "on line pulley" calculators. I've done a lot of motor swaps over the years, so I'm not too intimidated by them.
I wouldn't use any motor less than 2 HP, preferrably a 3 HP. My 8" Grizzly had a 2 HP, and seemed fine however. My 13" jointer/planer has a 3 HP for the extra width.
New "take off" motors are available on Ebay:

Good price on this new one:
The problem I see with swapping out the motors is that I have not been able to find a 66 Frame motor, short of a new Baldor for $900. The dimensions on any other frame won't line-up with the mounting brackets. Plus, the 66 frame is the only one with a 0.75" shaft, which means I'd have to find a new pulley and probably a new belt.
 

·
Registered
Joined
·
4 Posts
Discussion Starter · #9 ·
The 37-315 is a very popular jointer made for years under the Rockwell and Delta name. I am almost positive it was available in both 3 phase and 110/220 single phase. You should not have an issue finding a motor for it.
It may have been available in a single phase, though I haven't found any reference to one. In any case, I've been unable to find a motor that has the same dimensional specs.
 

·
Registered
Joined
·
26,892 Posts
I purchased a used Rockwell 8" jointer, model 37-315. It has a 3-phase motor. I did not realized that I could not easily run 3-phase electricity in my home workshop. I'm wondering now if it would be easier to buy a converter to run the 3-phase motor or swap-out the motor for a single phase. I'm not sure if this model was originally available with a single phase motor. Does anyone have any experience with this?
I bought a machine knowing it was three phase. I had in mind replacing the motor when I bought it however it turned out the motor wasn't replaceable so I got a rotary phase converter to run it. Then once I solved the three phase problem I didn't think anything about buying a machine that needed it. You can get some really great machinery cheap that run on three phase so the converter helped me. That may not work with a VFD, you pretty much need to buy one for each machine where the rotary converter operates all four machines I have now.
 

·
Registered
Joined
·
450 Posts
My table saw my father ran it with 3 phase 220V, I don't have that but the motor had a plate which showed how to run it 1 phase, just had to switch a couple of wires very simple, I do notice power loss if the belt tension gets to tight with like a 45 degree bevel rip which will stall it out.
 

·
Registered
Joined
·
1,118 Posts
Thank you for the response! I've been looking for a single phase motor to swap out, but am not finding a perfect match. The 3-phase motor that came with it is a "Frame 66, Type P". One of the sites I saw had a bunch of new motors that were 56 frames, but no 66. I was thinking I could add a board or something to mount the frame. Other similar motors have a 0.625 shaft, but mine is a 0.75.
a 6"x8" piece of 3/4 plywood would make an adapter
if i can make a pine 1x4 carburetor adapter to get my buddy mazda rotary home (and out of my garage)
you can make a plywood motor adapter for a jointer
one set of holes and bolts for 66p frame and another set for the 'other'
 

·
Premium Member
Joined
·
5,170 Posts
I'm concerned about getting the correct VFD. I've heard it's best to oversize the converter. My motor is a 1hp, but I was thinking of going up to a 3hp VFD to have more available power and also in case I ever pick up another shop tool running 3hp 3-phase.
Oversizing the converter is old advice, doesnt really need to be done with modern VFDs. Whatever power theyre rated for, thats the size motor you can put on one, a 3hp VFD will run a 3hp motor. Well, more accurately a VFD rated for 20 amps can handle a motor that draws 20 amps, but you get the point. Frankly, im not even sure that that advise is true for older VFDs

Important note, VFDs are meant to only power 1 motor. If youre looking for something to hook multiple tools up to, you need something like a rotary phase converter
 

·
Registered
Joined
·
490 Posts
I worked on an industrial project with several conveyors in series where they needed to run at the same speed. The setup was a large VFD feeding several starters, one starter for each motor. This was a specialized application, not comparable to a home shop.
 

·
Premium Member
Joined
·
5,170 Posts
I worked on an industrial project with several conveyors in series where they needed to run at the same speed. The setup was a large VFD feeding several starters, one starter for each motor. This was a specialized application, not comparable to a home shop.
Addendum to my last, consumer-grade VFDs are generally meant to only power 1 tool, commercial-grade arent as limited
 

·
Registered
Joined
·
229 Posts
Oversizing the converter is old advice, doesnt really need to be done with modern VFDs. Whatever power theyre rated for, thats the size motor you can put on one, a 3hp VFD will run a 3hp motor.
Not completely accurate. The reason why a VFD sometimes needs to be oversized is for the input rectification, not the output power consumption.This is because most VFDs are rated for 3-phase input, but in order to operate from a single-phase source, one bank of the diode bridge will not be providing current to the DC bus.

Typically these days, most VFDs smaller than 3hp already have input rectification oversized as necessary for single-phase input, and therefore, they do not need to be derated.

VFDs above 3hp are less likely to be rated for single-phase input, and therefore, they should be derated.

That not withstanding, a jointer motor will rarely ever see anything close to 100% capacity, so the VFD would never need full power from the DC rectifier.
 
1 - 16 of 16 Posts
Top