There are several methods:
First, keep the existing motor unchanged, install a reducer at the output end of the motor, and choose a speed ratio of about 2:1, which can reduce speed. at around 700. But the torque (power) can be doubled.
Second, replace or transform the existing four-pole motor into an eight-pole motor, and the rotation speed will be reduced to about 700. If the motor power remains unchanged, the torque can also be doubled .
Third, keep the motor unchanged and use a constant torque inverter, but the price is relatively expensive.
The specific cost is closely related to the power of the engine you use.
If you wish to replace the pulley, this is of course calculated according to the circumference, or according to the diameter.