FEM Duty Classifications

TECHNICAL GUIDE REVISION 0

QC 2000 DUTY CLASSIFICATION

2

According to FEM classification, two fundamental criteria must be taken into account: Ø Type of duty (load spectrum)(k) Ø Average daily operated time (Tm)

I) Type of Duty (load spectrum) I.a ) Approximate determination LIGHT (k < or = 0.5) Occasional full load. Usually light load. Small fixed load.

Load %

HEAVY (0.63 < k < or = 0.8 ) Repetitive full load. Usually average load. Heavy fixed load.

100%

40% 10% 10

40

VERY HEAVY (0.8 < k < or = 1 ) Usually almost full load. Very heavy fixed load.

73% 47% 20%

17 17

40%

50

100%

17

100%

50

Operating time % Load %

MEDIUM (0.5 < k < or = 0.63) Occasional full load. Usually light load. Average fixed load.

Load %

17

50

Operating time % Load % 100%

90

50

I.b) Strict determination For an exact classification into groups the cubic mean value k referred to the load to be lifted is required. It is calculated using the following formula:

k  = 3

3

æ  C 2 ö æ T 2 ö +ç ÷ .ç ÷ è Cm ø è Tm ø

3 ö æ  C 3 ö æ  T 3 ö +ç ÷ . ç ÷ +. . . .÷ è Cmø è Tm ø ø

Since the life of the mechanism is inversely proportional to the cube of the load. Symbols: n n n

C1, C2, C3, ... useful or partial load T1, T2, T3, ... daily daily operatin operating g time under under useful useful or partial partial load Tm = T1+T2+T3+... average daily operating time

R&M Materials Handling, Inc Springfield, Ohio USA

10

Operating time %

Operating time %

æ æ  C 1 ö 3 æ  T 1 ö çç ÷ .ç ÷ è è Cm ø è Tm ø

80%

4

4/2/2001 QC2000TECGD

TECHNICAL GUIDE REVISION 0

QC 2000 DUTY CLASSIFICATION

2

II) Daily Operatingd Time (Tm) Tm is the total daily operating time with load and without load

III) Determination of the FEM Classification Class of duty (load spectrum) service k k < 0.5 light medium 0.5< k