<!-- from fixya rte -->Grinder motor not running speedly - KitchenAid Stand Mixer Fruit/Vegetable Strainer and Food Grinder FVSFGA

It's possible that the variable speed control may be the issue with your Delta 23-197 grinder. However, before attempting to bypass it, there are a few other things you can check.
First, make sure that the grinder is properly plugged in and that the power outlet is functioning correctly. Check the power cord and make sure that there are no cuts or breaks in the cord.
Next, check the switch and make sure that it is properly engaged. If the switch is faulty, it may need to be replaced.
You can also check the brushes on the motor to see if they are worn out or damaged. If the brushes are worn out, they will need to be replaced.
If none of these troubleshooting steps resolve the issue, it may be possible to bypass the variable speed control. However, this is not recommended unless you have experience with electrical wiring and understand the risks involved.
If you do decide to bypass the variable speed control, you will need to identify the wiring that controls the speed control and connect the wires together to bypass the control. However, keep in mind that this will result in the grinder running at full speed all the time and may shorten the life of the motor. It's always best to have a qualified electrician or technician perform any electrical modifications to your tools.

Those little, high speed grinders do not respond well to that sort of thing. Many do not advise running more than 30 seconds at a time as they will overheat. Yours had a stone lodged so that the motor couldn't turn so the fan blades on the motor couldn't cool the motor either. I suspect it's time for a new one as repairs would likely cost more than it would cost to replace.

Try it with less beans, or the motor is not running at full speed, no other fix

you have a problem with the bearings or the motor/brushes are burnt. Does this tool arc when running. If so I would check the brushes first, unplug the tool and remove them and while they are out rotate the motor slowly and look at the commutator bars for excessive discoloration or unusual wear.

does it run freely?as in not seem to be lugging from bad bearings in the motor shaft,then check the speed control board for a shorted triac/scr transistor

Unless the motor is a brush type universal unit, there is commonly no way to change the speed of an induction motor. There are AC motor speed control units available, but cost more than the grinder as they change the frequency as well as the voltage. There are speed controllable grinders available that use brushes so that simple electronics can control speed. Hope this helps!

if this is a cap start motor and not a centrifugal start run motor then bad cap is good place to start

The capacitor is easy to change and can be matched once you remove it by any electronics parts house.

The RPM rating of the die grinder is the deciding factor in the tool’s usage. A die grinder with a lower RPM is best used for fine grinding and finishing work. Speeds lower than 10,000 RPM are best for this function. A die grinder with an RPM between 10,000 and 20,000 is great for creating rough finishes and minor buffing jobs. If the die grinder will be used to remove metal burrs or to cut metal, it must have an RPM rating of over 20,000 and a no-load speed of at least 30,000 depending on the RPM rating.