There are several types of VAM pumps available on the market today, each with its own advantages and disadvantages. It's important to choose the right one for your project based on the specific requirements you have. here is a brief overview of some of the most popular VAM pumps: 

-Piston Pumps: These pumps use pistons to move fluid through the machine. They're relatively inexpensive and easy to maintain, but they don't work well when submerged underwater or under high-pressure environments.

-Rotary vane Pump: This type of pump uses blades attached to a revolving rotor instead of pistons. The blades help circulate fluid more efficiently than piston pumps and can handle heavier loads better than other types of VAMSs. However, they tend to be more expensive than piston pumps and can be less reliable in wet conditions or under high-pressure situations.

-Servo Motors: servo motors are sometimes referred to as "high torque" because they offer higher power outputs relative to other types of motors used in VAMSs.. They also have greater flexibility – allowing them to be adapted for different applications without needing modifications.. However, servo motors are often more expensive than other options and may require additional maintenance.