Hydraulic motors offer superior efficiency, durability, and power versus electric motors. These attributes make them an ideal choice for many applications, such as construction, mining, and agriculture. In the sections below, we explain what hydraulic motors are, their principal advantages, and when they provide a superior option versus their electric counterparts.

What Are Hydraulic Motors?

Like electric motors, hydraulic motors use energy conversion to generate power. They harness the pressure and flow of the given fluid and convert it into torque and rotational force.

How a hydraulic system works differs to some degree by the type of motor and its application, but they all function on the same basic principle. The motor system’s pump acts against an incompressible fluid within the system by pushing against a piston inside a cylinder. The piston’s movement then converts into a rotational force.

The force a hydraulic motor produces depends upon the length and girth of the hydraulic cylinder and piston. When more power is required, engineers can increase the size of the cylinder.

One significant advantage of hydraulic motors is their large power-to-size ratio.

Types of Hydraulic Motors

Manufacturers make many types of hydraulic motors. The difference in their design is based on hydrodynamic and hydrostatics theories. The most prevalent kinds include the following:

● Axial piston motors
● Radial piston motors
● Gerotor Motor
● Vane Motor
● Gear Motor

Pros and Cons of Hydraulic Motors

Hydraulic motors come with many benefits, including the following:

Pros

● Generation of very high output force in comparison to input force
● More accurate movements versus other motor types
● Can function optimally in harsh environments
● Stops and starts readily
● Capable of slow and precise movements while moving heavy loads
● High torque capacity despite a system that is a fraction of an electric motor’s size
● Stores energy in accumulators as fluid under pressure, creating a more efficient system
● Uses no power while holding a standstill load
● Motor size can be reduced to the dimensions needed for the average load
● Remote munting is a possibility. Only the accumulator, actuator, and control valves must be located near the application close

Cons

● Higher initial cost
● More maintenance and cleaning needed, especially for the filters, hydraulic pumps, and oils
● Hydraulic fluid leaks increase safety hazards environmental impact
● Hydraulic systems require multiple components, including actuators, accumulators, release valves, and the hydraulic fluid
● Operation causes high vibration and leals
● Very noisy operation
● The hydraulic fluid requires frequent inspections, cleaning, and top ups
● More lost efficiency due to heat loss

Pros and Cons of Electric Motors

Electric motors come with some advantages, such as lower initial cost, but their overall operational effectiveness pales in comparison to hydraulic motors. Here are the main pros and cons of electric motors:

Pros

● Lower cost verus hydraulic units
● Fast RPMs
● Excellent positioning accuracy
● Programmable speeds and stop positions
● Optional VFDs offer precise control and feedback on motion and force
● Systems are not readily scaled
● Smooth, quiet operation

Cons

● Complex installation and troubleshooting difficulties
● Install and repairs often require an electrician or engineer
● Electric motor components have sensitivity to water, dust, dirt, and other contaminants
● Heavy loads can cause the motor to stall, possibly causing damage
● A gearbox may be required to operate the load at a slower speed, a condition that negatively impacts efficiency
● Underwater use can be a challenge due to waterproofing difficulties
● The size motor needed for high torque may be impractical
● Oversized motors needed to meet the maximum load requirements
● Large motors use more energy
● Electric motors must be mounted close to applications

Applications Best Suited to Hydraulic Motors

Electric motors can complete the same jobs as hydraulic motors but hydraulics have superior performance in many applications, including the following:

Applications Best for Hydraulic Motors

● Heavy-duty equipment applications
● Construction
● Mining
● Agriculture
● Metalwork
● Vehicle braking
● Where much back-and-forth motion is required
● Where a large quantity of motor axes are needed
● Applications where one actuator moves another
● Where consistent torque is needed

Applications Best Suited for Electric Motors

● Where continuous motion is called for
● Where precision positioning is needed
● Where fine speed control and high speeds are required
● Where hydraulic fluid leaks cause problems
● Where lower maintenance is desired
● Applications lacking space for an accumulator, actuator, cooler, or filtration components

These pros and cons lists can seem to make a decision between a hydraulic- or electrical motor difficult, but the choice should be easier when you consider the application, space available, and maintenance requirements. For jobs with limited space, requiring high amounts of torque, or underwater use, hydraulic motors are the only good option. The increased efficiency of a hydraulic motor more than makes up for the additional cost and maintenance.

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Our hydraulic repair services include hydraulic pump and motor repair, Vickers classic factory rebuilds, hydraulic field piping repair, reverse engineering services and more. Our commitment to consistent high-quality work and on-time delivery has made us a #1 Choice in the industry. Call us to learn more