Technical Data  Reducers  DCBL Hypoid Motor / Gear Reducer for Servo Motors  Selection

Calculating Moment of Inertia

1. Moment of inertia of rotational body

Moving body Moment of inertia formula
SI Unit 		GD2formula
{Gravity unit }
When center of rotation is the same as shaft Moving body I= 1 2 Mr2

(kg・m2)

 GD2= 1 2 WD2

{kgf・m2}
Moving body I= 1 2 M(r12+r22)

(kg・m2)

 GD2= 1 2 W(D2+d2)

{kgf・m2}
Moving body I= 1 12 M(A2+L2)

(kg・m2)

 GD2= 1 3 W(A2+L2)

{kgf・m2}
When center of rotation is different from shaft Moving body I=M r2 2 +R2

(kg・m2)

 GD2=W 1 2 D2+4R2

{kgf・m2}
Moving body I= M 4 A2+L2 3 +4R2

(kg・m2)

 GD2=W A2+L2 3 +4R2

{kgf・m2}
Moving body I= M 12 (A2+4L2)

(kg・m2)

 GD2= 1 3 W(A2+4L2)

{kgf・m2}

2.Moment of inertia of parallel moving body

Moving body Moment of inertia formula
SI Unit 		GD2formula
{Gravity unit }
Moving body I=M1r12+M2r12+ M3r12+M4r22 2

(kg・m2)

 GD2=W1D12+W2D12+ W3D12+W4D22 2

{kgf・m2}
Moving body I= 1 4 (M1+M2)× V π n 2

(kg・m2)


n:Motor revolution speed to V (r/min)		 GD2=(W1+W2)× V π n 2

{kgf・m2}


n:Motor revolution count to V (r/min)
Moving body I= 1 2 M1r2+M2r2

(kg・m2)

 GD2= 1 2 W1D2+W2D2

{kgf・m2}