Spindle vs Induction Motor

[tryme96z]

Looking for feedback on a repair/upgrade idea. I have a Dewalt 735 (Type 1) planer which is known for destroying it's proprietary induction motor ("2 hp", 120 vac, ~20K rpms and 14 amps running). It can destroy the armature or the field or both along with the casing. A entire motor replacement is not sold, but you can buy the parts and rebuilt it. But after hours of reading and am considering another route of repair: A Chinese cnc spindle and vfd. It should physically still fit in the Dewalt's cover, have high enough rpms, I believe has the torque. It will be a good 30% more to do this repair, but I think it could be the long term fix compared to another Dewalt motor that is likely to burn up after 3-4 years. From a rotational power device, I believe the spindle will have the torque and rpms to make this a very slick upgrade. Yes this glosses over the amount of effort it will take to mount the spindle attache the DeWalt belt pulley. I do have experience using, setting up, and configuring a Chinese spindle and VFD...nothing to learn on that facet of the project.


Question: Why might using a CNC type spindle with a VFD be a bad idea to replace a small proprietary induction motor ("2 hp", 120 vac, ~20K rpms and 14 amps running)?


If you are scratching your head on the "why" for effort/time/benefits: I like the physical size and features of the 735. I cannot dedicate the space for a 15" or larger more industrial planer.

For Reference:



Motor in the top left:

A typical Chinese Spindle Kit:

 

[Beerhippie]

What's the duty cycle on the spindle motor?

 

[tarbellb]

This looks to be a very cool potential project. No insight on your approach but def interested in the outcome.

Keep us posted OP

 

[johnre]

Why might using a CNC type spindle with a VFD be a bad idea to replace a small proprietary induction motor ("2 hp", 120 vac, ~20K rpms and 14 amps running)?

1. You have no need for the reversing feature, like you would, say, for a drill press application where you could use it to back out a stuck bit.
2. You likewise don't need variable speed - that cutter head is made for running at one rpm, which per their spec is 10,000 rpm no-load. This is half the speed of the motor through a 2:1 belt reduction (and BTW that motor is a brushed universal type, not an induction motor).
3. So it's going to run full speed, continuous duty. You know best if there are suitable spindle motors since you've worked in this technology with CNC, but I did and a quick search can't find any that meet the requirements.
4. There will be the usual issues with the motor's flange or base mount, shaft diameter, air cooling, etc. And note on the planer you've got three things to hook up - the cutter head (through a belt system), the feed (through a gearbox), and the dust fan (probably direct attach) - and probably all with unique hardware.

This will be a challenge, but hey, this is the Garage Journal, and we like such challenges. I'd be the first to wish you good luck if you decided to take this on!

 

[octane_matty]

I’m interested in this too

Since you already have one any chance you can tell me the diameter of the shaft that the pulley sits on? Dimensions of the motor?

I’m wondering if a 1/2” router motor might be another option?

 

[RoninB4]

I have the same planer, am interested in how this turns out.