I think that the main way that a project manager can motivate their team is by being passionate about the project they are working on. I think that this can be achieved by only managing projects that one is truly excited about. By leading a project that one is excited and passionate about you can one find individuals to work on your team that share this excitement, and two motivate your team to work hard on a project. Moreover, I know that realistically there will not always be projects that one truly will enjoy working on. This is where the financial motivators come in. Knowing that one will be getting paid, and maybe even get bonuses for doing a good job on a project should also serve as motivators.