Differential pressure
the pressure difference between p 1 and p 2 . The differential pressure can be positive or negative, depending on whether p 1 is greater than p 2 or smaller than p 2 (Figure D 23) . The expression "di
Pressure flow
Flow that is produced in the gap between two chambers with different pressures p 1 and p 2.
Transmission pressure
influence of a transmission ratio before the smaller area A 2. It is Ratio of piston areas α α greater than the pressure p 1 acting on the larger area A 1 by the ratio of the piston areas.
Over-excitation
however, the switching duration must be reduced as compared to the nominal voltage ( Table U 1 ) (cf. Figure G 16).
Speed ratio
The speed ratio of a hydrostatic transmission is defined by the ratio of the pump speed n 1 to the motor speed n 2:
Impedance Z
since these are associated with different units: electrical impedance Z mechanical impedance Z m specific impedance Z S acoustic impedance Z a [...] elements of impedance are frequency-dependent, this results in a frequency dependency for impedance Z (Figure I 2) . Depending on the application involved, it is important to distinguish clearly between various [...] General form of resistance. Impedance Z is a complex physical variable (actual and notional element), which takes the following form R = resistive element of resistance jωL = inductive element of resistance
Neutralisation number
content of a mineral oil . It indicates how many mg of potassium hydroxide are needed to neutralise in 1 g of oil the free acids generated during operation. Since the acid content is dependent on ageing, the
Hydropneumatic accumulator
withdrawal of the usable volume in accordance with the ratio of gas capacity to oil volume (Figure G 1) . Alternative: spring accumulator , weight accumulator .
Safety regulations
regulations of the institutions for statutory accident insurance and prevention include: ZH 1/457 and ZH 1/52 and ZH 1/74; VBG 7n5.2 Hydraulic presses, VBG 8 Winches, Lifting and Hoisting Devices, VBG 16 C [...] VBG 40 excavators, loaders, etc. There are also DIN standards and guidelines: DIN 24 295 Pumps and pumping sets, DIN 24 346 Hydraulic systems, DIN 31 000 General safety guidelines, VDI guidelines 3229 Technical [...] tools, hydraulic equipment. Separate regulations apply for the particularly dangerous accumulators: DIN 24 552 Hydraulic accumulators in hydraulic systems, AD data sheet A2 Safety equipment to prevent overpressure;
Kinematical viscosity v
(°E), and then in stokes or centistokes (cSt), but is now given in m 2 /s or mm 2 /s. cSt can be converted as follows: 1 cSt = 1 mm 2 /s