Sewing Machine Motor for Drill Press - Feasible?

[Davefr]

I stumbled on this while brainstorming for the perfect drill press motor.

Criteria:
- Std 120 VAC, 1 ph
- Wide speed range
- Approx. 3/4HP
- Integrated speed control self contained within motor

Apparently these motors are for commercial sewing machines and not all that expensive.

The challenges would be to adapt the shaft to the DP's pulley and possibly modifying the mount to the NEMA 56 pattern.

Has anyone tried it?

https://www.amazon.com/dp/B001VK9YH8/?tag=atomicindus08-20

 

[rlitman]

It's a brushed motor. They have far higher stall torques than an induction motor, so the HP rating will appear to be quite inflated, compared to the rating of an induction motor that has the same usable power (at operating speed). Figure on more like 1/4 HP out of it.

On top of that, industrial sewing machine motors have a clutch. That's what that black plastic arm in front controls. If you're not pulling on the arm, the pulley does not turn.

I absolutely could see this on a REALLY small DP. I think it would be excellent for example on my Hamilton Sensitive drill press (a 1/4" chuck tabletop machine). Especially if I could hook up that clutch to a foot pedal control (should be easy enough with just a chain hanging a ring large enough to put your foot in that's just above the floor).

But I really couldn't see this running a floor standing DP.

 

[Davefr]

It's a brushed motor. They have far higher stall torques than an induction motor, so the HP rating will appear to be quite inflated, compared to the rating of an induction motor that has the same usable power (at operating speed). Figure on more like 1/4 HP out of it.

On top of that, industrial sewing machine motors have a clutch. That's what that black plastic arm in front controls. If you're not pulling on the arm, the pulley does not turn.

No, these are brushless high torque DC servo motors and they don't have a clutch.

http://www.consew.com/View/CSM550-1-Servo-Motor

 

[catalytic]

That looks to me like a standard DC motor and rheostat control (could be wrong). Old school sewing machines used a different system.

If so, you can buy them in any size you want, same as you would a VFD/motor combo. Most industrial mfg have switched to VFD/motor control, but they used DC for a long time...it will work fine when properly sized. They do tend to be long, heavy motors, though.

 

[rlitman]

Not brushless. The brush caps are obvious in all the pictures. It would be pretty awesome if were brushless, but sorry to say, they are not.

I hadn't realized they were servo controlled. Interesting! Ok, so I guess the "clutch" is just a switch, and is there to make it an easy retrofit into a standard commercial sewing machine. That should be easy enough to bypass or make use of anyway. Anyway, as a switch, you don't have to worry about drilling torque destroying the clutch. That's a plus.

Being servo controlled is nice. It means that the speed control is actually useful. You don't lose power like with an external electronic speed control (where running at half speed might lose 90% of your torque).

 

[rlitman]

That looks to me like a standard DC motor and rheostat control (could be wrong). Old school sewing machines used a different system.

If so, you can buy them in any size you want, same as you would a VFD/motor combo. Most industrial mfg have switched to VFD/motor control, but they used DC for a long time...it will work fine when properly sized. They do tend to be long, heavy motors, though.

Servo control is much better than rheostat. It utilizes tachometer on the motor that sets the PWM pulse width to keep the motor running at the chosen speed.

Let's imagine it is a 3450 RPM free-speed motor. At no load, to achieve 1750 RPM, it might have a 50% on pulse width. As load increases, the pulse width will increase to maintain the rotation speed. It can increase to as much as 100% (full motor torque) as required.

A true rheostat isn't really useful for a motor, as it would burn out quickly. External motor speed controllers use PWM just like the servo control, BUT they have no feedback to the motor speed. So, let's imagine the same motor above, with an external speed controller at 50% pulse width (ok, so a speed controller isn't using DC pulses, but is instead shaving the AC waveform, but the net effect is analogous). At no load, the motor will turn at the desired 1750 RPM. BUT, once you put a load on the motor, it will quickly slow down, as the power input has been capped at 50%.

 

[Davefr]

Not brushless. The brush caps are obvious in all the pictures. It would be pretty awesome if were brushless, but sorry to say, they are not.

I hadn't realized they were servo controlled. Interesting! Ok, so I guess the "clutch" is just a switch, and is there to make it an easy retrofit into a standard commercial sewing machine. That should be easy enough to bypass or make use of anyway. Anyway, as a switch, you don't have to worry about drilling torque destroying the clutch. That's a plus.

Being servo controlled is nice. It means that the speed control is actually useful. You don't lose power like with an external electronic speed control (where running at half speed might lose 90% of your torque).

Here's one that is brushless:
http://www.consew.com/Files/112347/PDF/Motors-Con-Serv1000.pdf