Choosing an 8A Drill

Depends on the drill design...

Reduce your chances of damaging either and get a two speed drill like this one. I bought one similar to this about 25 years ago. One of the best purchases I ever made. With a two-speed gearbox, the extra mechanical advantage will save the motor and drive electronics. The low speed setting is 0-1,000 RPM, and the high speed setting is 0-2,500 RPM.

https://www.milwaukeetool.com/Products/Power-Tools/Drilling/Hammer-Drills/5387-22

The amount of power required for drilling increases both with the drill speed and with how fast you are trying to cut (feed rate). Reducing the speed with the speed control and limiting the feed rate will reduce the load on the drill.

If you're slowing it down with the speed control, you won't harm the speed control. The variable speed is achieved by switching on the AC current to the motor at a delayed point in the AC waveform to limit the current. It is not a series potentiometer that gets hot from limiting current with resistance, so running at reduced speed will not burn it out.

http://electronics-diy.com/1000w-ac-motor-speed-controller.php

If you're slowing it down by running the speed control full and feeding it fast enough to slow the drill to 500 RPM, you may well damage the motor and likely ruin the bit from overheating.

Its a mixing application, high torque requirement, I wonder if it will deliver the torque at current thresholds such as to minimize damage to brushes, motor, Scr, thyristors, etc, I'm not worried about the control potentiometer circuitry.

What you really need is a gearbox to reduce speed and increase torque.

It will likely be fine if you keep the duty cycle similar to the original design for drilling a hole, not much difference in the load characteristic. As others have said, the speed controller will be self protecting. Wear and tear on the motor will be similar to using it to drill holes.

I will try this one, Thank you for your answers and these circuits will serve me for troubleshooting in case!, thank you very much!

https://www.homedepot.com/p/Hilti-UD-30-Universal-6-5-Amp-1-2-in-Metal-Drill-Keyed-Chuck-273756/303197279?MERCH=REC-_-PIPHorizontal2_rr-_-204514540-_-303197279-_-N

Try it, and please let us know what color the smoke was.

Will absolutely do and post pictures, hope it wont happen. I wont use it often but when I will I want to be able to have some torque/speed control

Hey for $65 just get one of these....

A tool designed for purpose works much better....

Those things can also be hired.

Hallo, Speed Controller Electronic unit & winding of drill machine can be protected from OVER CURRENT problem. But it is subject to if you would have tuned Speed Controller Electronic unit properly when it is running under Normal running condition. It means that Speed Controller Electronic unit output current must be locked at say 8amp initially.

See objective is that there should not be any damage which results in Accident and your financial loss Accident also may results like heating/burning of cables conductor of drill machine due to more current flows thru cable conductor than its rated capacity.