Question 1

Is there a power-off activated version?

Accepted Answer

ESTAT clutches can be configured to remain engaged for minutes to hours after losing power, or to disengage within milliseconds. Whether you want the clutch to disengage immediately or remain engaged for an extended period of time, we can design a solution for you.
To see an example of the use of a voltage reservoir to enable power-off engage behavior, click here.

Question 2

Are clutch designs available for my custom requirements?

Accepted Answer

Many standard ESTAT products are modular, enabling easy scaling of force or torque capacity with very little design effort by stacking multiple units into an assembly. More involved customization is available upon request, with minimum order quantity requirements. Please reach out to info@estat.tech for custom requests. We are eager to design an actuation solution for your application!

Question 3

Can your clutches be used in dissipative braking applications?

Accepted Answer

While ESTAT clutches are designed to slip and absorb some dynamic friction energy, they are currently best-suited for static-engage applications. We are actively investigating new materials which are more appropriate for high-temperature and high-friction applications, and we hope to offer a dissipative braking product soon.

Question 4

How much power do your clutches draw?

Accepted Answer

Our clutches operate on milliwatts of power, as opposed to tens of watts for traditional electromagnetic clutches. They reach a peak current of ~5 mA while the charges are accumulating on opposing sides of the clutch. Once charged, they only require micro- or nanoamps to remain engaged (to compensate for the trace leakage current through the dielectric).

Question 5

What’s the operating voltage?

Accepted Answer

Operating voltage varies between applications, and operators can modify the operating voltage in real time to vary the force or torque output. However, most applications require voltages between 200 and 500 V.

Question 6

How wear resistant are these clutches?

Accepted Answer

ESTAT clutches are shockingly robust for being so thin and flexible. We have two primary internal tests to evaluate wear resistance of rotary clutch products.

First is our long-term reliable hold test. This involves applying the operating voltage to engage the clutch, ramping to the clutch’s rated torque, holding that torque for 1 second, and then disengaging. This counts as one cycle. ESTAT clutches are capable of millions of reliable hold cycles with no change in performance.

Second is our longevity slip testing, which involves engaging the clutch at the operating voltage and then ramping torque beyond the clutch’s rated torque, causing the clutch to slip. ESTAT clutches are capable of sustaining hundreds of thousands of these slip cycles before losing performance.

Question 7

So it’s basically magnetic attraction holding the surfaces together?

Accepted Answer

No, our technology is notably not magnetic. Our products use electrostatics, which makes them lighter, more compact, and vastly more efficient than traditional electromagnetic clutches and brakes.

Imagine rubbing a balloon against your hair and having it stick there. Positive charges build up on one object and negative charges on the other. The opposing charges are attracted to one another, which causes the balloon to stick to your head. Our products operate on the same principle, but use advanced dielectric materials to hold significantly more electric charge than your hair or a balloon can, which means that the attractive force is much stronger.

Question 8

How is this different from an electromagnetic clutch?

Accepted Answer

Our technology is more efficient, lighter, more compact, and safer.

Electromagnets require constant current to maintain a magnetic field, whereas our clutches operate via a voltage potential. Once the voltage differential is applied, the electrostatic field is established near-instantaneously and requires almost no maintenance current. That makes our clutches significantly more efficient. Electromagnets also require bulky metal coils to generate their magnetic fields, making traditional clutches cumbersome and heavy. Ours make use of advanced 2D materials, which makes them light and compact. Lastly, because electromagnets operate on constant current input, they get extremely hot. Our clutches generate virtually no heat and contain no moving parts, which makes them a safer alternative – particularly for medical robotics or exoskeletons.

Question 9

What are the flexible films made of?

Accepted Answer

Each flexible film is composed of three layers. The outermost layer is a strong, transparent polymer called biaxially oriented polyethylene terephthalate (BoPET). The middle layer is a very thin conductive material, typically sputtered aluminum. Finally, the middle layer is a dielectric ink—a composite material with a polymer matrix and dispersed ceramic particles. It’s the dielectric ink layer on two adjacent flexible films that come into contact when the clutch is engaged.

FAQ