Calculation Theory

Information courtesy of

Max disc speed

ω₂ = ω_O + (0.4 M_L/J_O) = ..................... sec^-1

The increase of disc speed resulting from free fall of the load.

ω_O = Initial speed of disc.
ω₂ = Disc speed at full torque occurring after 0.4 sec including all normal time delays.

The formula above, gives an approx value in normal cases. For accurate calculations, use the following relation.

ω₂ = ω₀(1+K) + t₀M_L/J₀

K = Over speed in per cent when brake signal is given.
t₀ = The reaction time for the total brake system, from brake signal (1) to braking torque (6).

The value 0.4 sec, can be shortened by careful attention to dimensioning of the return line and temperature influence to oil viscosity. At very low pressure drop 0.15-0.2 sec, can be achieved.

Example of reaction time in ideal case.

Reaction time BSFG 408 A at 1 mm air gap and including one directional valve size NG6, with 1 m total length of Hose. Viscorisity 30 cst.

1. Brake signal
2. The piston starts to move
3. The pad reaches the disc and M_B increases
4. The counter pressure drops faster
5. The counter pressure = 0
6. Max M_B is achieved