Comparing MR to Other Technologies
Q. What are the differentiating factors of MR technology to conventional electro-mechanical approaches?
A. Our MR technology provides variable, resistive control of force in near real time. As compared to traditional electro-mechanical technology, MR has important advantages:
- Infinitely variable force resistance within a wide control range. For example, MR dampers can easily achieve large forces at very low speeds.
- Fast acting; almost instantaneous response. The response time of an MR fluid is much less than one milli-second, so the response time for most practical MR devices is controlled by the time it takes for the current source to establish the magnetic field in the fluid. With proper design, system response times of 2-10 milli-seconds are achievable.
- Mechanical simplicity. Unlike electro-mechanical valves there are no moving parts, which reduces complexity and improves cost and reliability.
- Low power requirements.
Q. What is the difference between Magneto-Rheological (MR) and Electro-Rheological (ER) fluid?
A. MR fluids are similar to ER fluids, but MR fluids are 20 to 50 times stronger. They can be operated directly from low-voltage power supplies and are far less sensitive to contaminants and extremes in temperature. Applied to a variety of devices, LORD MR fluid technology can provide flexible control capabilities in designs that are far less complicated and more reliable than with ER technology.
Q. What is the difference between MR fluids and ferrofluids?
A. Ferrofluids are often confused with MR fluids. Both fluids are suspensions of iron containing particles in carrier oils. But where MR fluids use micron-sized, pure iron particles, ferrofluids consist of nanometer-sized iron oxide particles. Ferrofluids do not show the yielding behavior characteristic of MR fluids in a magnetic field as their particles are too small. Instead ferrofluid flows to and is attracted by the magnetic field. Even in a very strong magnetic field, ferrofluids always remain liquid.
Applications for ferrofluids include speakers and vacuum seals. MR fluids are not appropriate for those applications. For more information about ferrofluids, we suggest visiting the FerroTec Web site.