The prime mover gives a hydraulic system power. The prime mover can be a gas or diesel engine, or electric motor. When selecting a prime mover, consider access to power, horsepower needed, and mounting style. The more horsepower the more flow (gpm) and pressure your pump can produce. If your system does not have easy access to electrical power, a gas or diesel unit may be needed. If your application requires your prime mover to fit in a small space, then a tank mounted electric motor could be an option.