Hi, Which motor is suitable to carry loading 250kg above? Geared motor with high torque? But How it can deal with the PIC16F877A?
ishah, Welcome!
Not sure what you're asking, but...
EXAMPLE:To raise 250kg 1m (in one minute) requires 250kg/m of torque. That converts to approx. 1808 ft/lbs which is approx. what a 3.3hp electric motor can produce, theoretically at zero RPM (gas, of course, would be at some higher RPM): not a "small" motor in what I would consider a general sense.
Or, in other words, there are lots of conversion sites out there. Pick the one you want to provide the power needed to peform the task you have in mind.
As to the next question I think your asking, yes, a geared, high torque device is preferable, if the speed at which the movement occurs is not an issue. The longer you are willing to wait for the task to be completed, the smaller the motor required to do the job. In the EXAMPLE above, if you're OK with the task taking 2 (two) minutes, then a 1.65hp motor will suffice: 5 minutes = 0.606hp motor, and so on.
As to controlling this device with a PIC: you can control anything you wish, not matter the size, so long as you interface the devices appropriately, i.e., very low power device initiating a much higher powered device system.
A little better, or more thorough explaination of what you are trying to do would be useful.