Why a Progressive Electronic Clutch?
Before getting into technical detail, I want to address why I think my Progressive Electronic Clutch (PEC) is even a good idea (at least for a trials bike) in the first place. A friend, who excels at geriatric motocross and rode trials in the past, was the most critical of the PEC concept. I respect his opinion. His criticism went along the lines of, why would you want this type of “clutch” if it's nothing more than an extra throttle? And if you can't store/release energy in a spinning flywheel, why complicate the operation of the controls?
It may come down to personal preference. I'll try to explain mine. One of my early trials mentors taught me to keep one (and only one) finger always, always, always on the clutch lever. It was probably the best trials advice I ever received and it transformed my riding. Now I'm completely dependent on the technique.
The throttle is a fairly coarse control on the 5.7 (it has just 72 degrees of rotation). You can certainly drive the bike with just the throttle, but by using my PEC you can achieve a much finer control. The throttle sets the maximum attainable and the electronic clutch modulates it. Of course, it's possible to completely ignore the PEC and use only the throttle if that's how you want to ride it.
Keeping a good grip on the bars is imperative in trials. (You don't grip the bike with your lower legs as in motocross since a wide stance is preferable.) For me, it's often difficult to alter the throttle setting during certain maneuvers while maintaining a good grip on the bars. Whereas, moving a single finger is much easier to accomplish. This is especially true if you have to “regrip” the throttle in order to achieve the required rotation.
Because the motor controller operates in “torque” mode, the rear wheel spins up quickly if you lose traction (as in a loose hillclimb). For me, small finger movements work better than temporarily closing the throttle to regain traction.
Whether or not a PEC is an advantage depends on the particular motorsport and the rider's skill. At the higher levels of trials, the clutch is used more like an on/off switch, but lower-level trials riders (and hard enduro riders) tend to slip it more.
Is my PEC as good as a mechanical clutch? No. Is it better than nothing? Yes.