Is setting high target for a sales employee considered good to motivate him?

Setting high targets can be tricky. According to my experience, setting up high target that seems hardly reachable can be demotivating from the start for an employee, as he believes that it can not be reached and therefore doesnt put an effort in trying to reach the target. But setting up high target and presenting to an employee what actions (like promotional activities) will be taken during the period in order to promote reaching that set target and implementing certain award to an employee for reached target is motivational for an employee and can bring good results.