Fuji Electric Frenic Mega Series - App. E Conversion from si Units

App. E Conversion from SI Units
A-21
App.
App. E Conversion from SI Units
All expressions given in Chapter 10, "SELECTING OPTIMAL MOTOR AND INVERTER CAPACITIES" are
based on SI units (The International System of Units). This section explains how to convert expressions to
other units.
[1] Conversion of units
(1) Force
• 1 (kgf) ≈ 9.8 (N)
• 1 (N) ≈ 0.102 (kgf)
(2) Torque
• 1 (kgf·m) ≈ 9.8 (N·m)
• 1 (N·m) ≈ 0.102 (kgf·m)
(3) Work and energy
• 1 (kgf·m) ≈ 9.8 (N·m) = 9.8(J) = 9.8 (W·s)
(4) Power
• 1[kgf･m/s] ≈ 9.8[N･m/s] = 9.8[J/s] =
9.8[W]
• 1 (N·m/s) ≈ 1 (J/s) = 1 (W) 0.102 (kgf·m/s)
(5) Rotation speed
2π
• 1 [r/min] =
60
[rad/s] ≈ 0.1047 [rad/s]
60
• 1 [rad/s] =
2π
[r/min] ≈ 9.549 [r/min]
(6) Inertia constant
J [kg•m
2
] : Moment of inertia
GD
2
[kg•m
2
] : Flywheel effect
• GD
2
= 4J
GD
2
• J =
4
(7) Pressure and stress
• 1 [mmAq] ≈ 9.8 [Pa] ≈ 9.8 [N/m
2
]
• 1 [Pa] ≈ 1 [N/m
2
] ≈ 0.102 [mmAq]
• 1 [bar] ≈ 100000 [Pa] ≈ 1.02 [kg･cm
2
]
• 1 [kg･cm
2
] ≈ 98000 [Pa] ≈ 980 [mbar]
• 1 atmospheric pressure = 1013 [mbar] =
760 [mmHg] = 101300 [Pa] ≈ 1.033 [kg/cm
2
]