servo motor generates heat

Hi, my towerpro 15kg generates heat also when it is stopped. How i could fix it?

You need to post a diagram showing how it is wired up and what power supply you have - a photo of a pencil drawing will be fine.

How much heat is it generating - is it too hot to touch? or just warm?

Even if the servo is not moving it will consume some power and it could consume full power while stationary if that is necessary to prevent a heavy load from moving.

...R

We would like to know which Arduino board, or which stepper driver board you are using and how the servo motor is powered.
Is it a YKS MG945 servo motor ?

You can use it at 5.0V instead of 7.2V.
The 5V pin of the Arduino board can not be used, the servo requires a lot more current.
The Arduino Servo library is able to Servo.detach(), some servo motors go into sleep mode. But only a few servo motors do that.

Servos consume power proportional to the load torque when stationary. You
probably have a lot of static torque so it has to pull a large current to hold
position.