Motor speed controller for Kally 1SM?

[grepper]

Inspired by Mr. Ken, I am wondering if has anyone put a speed controller on a Kalamazoo 1SM?  If so, what did you use?  I suffer a total lack of understanding concerning AC motor speed controllers. 

[Komitadjie]

Huh... I haven't, I've never found mine to be moving too quickly for any given use. What 'ya working on?

I don't imagine it would be impossible, although you might lose some horsepower... If you're doing small stuff, you shouldn't need that full third-horse anyway I'd think. Aaron is very active on Facebook, incidentally, I'd bet he could answer that question for you in a snap.

[grepper]

Honestly I've never thought the Kally runs too fast either. Heating of the blade is never a problem. I just thought it would be interesting to play with slower speeds. I have no idea what a speed controller would cost so I don't know if it would be worth it just to play with or not. Less than $50.00 then maybe. $400.00 nope.

[Rupert Lucius]

Grepper

Impossible to control the speed of the AC single phase motor (lowering the voltage - will soon ruin the motor).

Go with a 220V 3 phase motor, between the 120 V wall outlet you will add a frequency controller that steps the Voltage up to the 220V required also controls the frequency to the motor, that manages motors RPMs.

Three (3) phase motor should be inverter duty rated. Not at all necessary - insurance to prevent problems.

Rupert

[Ken S]

Grepper,

I am not familiar with the Kallie, however, The Penn State Industries variable speed motor costs $129. (They go on sale periodically.) With the Viel, either the motor shaft has to be reduced to .5" or the Viel pulley needs to be bored out to .59". I had the shaft reduced and the switching reworked. My cost was $150 for the job. I think a small town machine shop might just bore out the Viel Pulley for $25. If you happen to have a metal lathe, you could probably do the modification work for free. So, I would guess between $150 and $200. 

For me, this is a hobby. If I was sharpening as a business and happy with my belt grinder as is, I would think twice about making that investment. I trust those more knowledgeable than me will post their thoughts.

Ken

[Jan]

Impossible to control the speed of the AC single phase motor (lowering the voltage - will soon ruin the motor).

Go with a 220V 3 phase motor, between the 120 V wall outlet you will add a frequency controller that  steps the Voltage up to the 220V required  also controls the frequency to the  motor, that manages motors RPMs.

Three (3) phase motor should be inverter  duty rated.  Not at all necessary - insurance  to prevent problems.

Rupert

Mr. Ruppert is correct!

It is difficult to change the speed of single-phase motors. The reason is, that those motors often use a capacitor to start/run the motors. Electrical properties of a capacitor depends on current frequency. The usage of Variable Frequency Driver’s will result in lowering the current in the start winding, which will cause that the motor will not start and will run irregularly.

As far as I know the VDF invertors are used mainly in fans and pumps.

Jan

[Ken S]

Jan,

The variable speed motor from Penn State Industries I installed with my Viel belt grinder seems to be working. I believe it is a DC motor and it has brushes. What puzzles me are the tachometer readings. The readings range from 2975RPM on full to 1246RPM on minimum. They are consistent, and the same with two tachometers of different design. What puzzles me is that the motor label states it is 1700RPM.

The motor controller supposedly has three potentiometers which can be adjusted. The motor is actually designed for mini lathes used in pen making. It claims to be a half horsepower, although that may be a sleight of hand "developed horsepower rating", the kind favored by marketing departments.

The Viel is direct drive. The fixed speed of the former quarter horse power motor, presumably 1725RPM, was plenty fast. I realize the Surface Feet per Minute varies with the pulley diameter.

I have contacted the support group at Penn State Industries for more detailed information. No response yet. 

The belt grinder works very well with the new motor. I sharpened a set of garden loppers. The operation was very controlled and quite satisfactory. I just wish I understood the motor process better.

I appreciate your expertise.

Ken

[Rupert Lucius]

Ken

Do not pay any attention to that label - the motor is DC and uses brushes - it is DC.

The motor is in safe operational range up to about +/- 3600RPM (I have been there done that).

Where/when we run into trouble is when  operated at tooo low of RPM range.

For what you are using your motor for is perfect application. 

You will want to maybe turn the top RPM's down a tad.  That is what the pot adj will do for you.

Contact Don when possible.

Rupert

[Jan]

Mr. Ken, I am not a motor specialist, I only know the principles how they should work. 

Generally the speed of a DC motor is proportional to the applied voltage while torque is proportional to the current.

The speed of a DC motor can also be increased (above the nominal speed) by field weakening, which reduces the current in the field winding.

[Rupert Lucius]

Forum

As usual Jan is "spot on".

Thanks Jan.

Rupert