To change the output flow of a fixed displacement pump, which of the following can be done?

Changing the output flow of a fixed displacement pump can indeed be influenced in several ways. The correct answer highlights that all listed options can contribute to altering the output conditions.

Changing out the cartridge of a pump can be necessary when a different flow rate is required that the current cartridge cannot satisfy due to design constraints. Different cartridges can be designed to deliver varying flow rates while maintaining the same displacement characteristics, which directly affects the output.

Increasing the RPM of the electric motor driving the pump can also increase the flow rate produced by the pump, even if it is a fixed displacement type. A fixed displacement pump delivers a specific volume of fluid per revolution, so by increasing the speed of the motor, you effectively increase the number of revolutions per unit time, thus boosting the total output flow.

Recirculating some oil back to the inlet is a method often used to manage flow rates and reduce pressure within hydraulic systems. By returning part of the output flow to the inlet, it allows for flow modulation and keeps the system stable, ensuring that the pump does not exceed its rated capacity in situations where not all output is needed.

Thus, all these actions provide feasible means to influence the output flow from a fixed displacement pump, confirming that the correct answer incorporates each of these