Liftket STAGEKET, Руководство по эксплуатации

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8 Duty rate of an electric chain hoist
Caution!
The duty rate and the number of operating cycles in one hour must not be higher than as
shown on the specification plate of the hoist or in a technical data table.
(European regulation FEM 9.683).
The duty rate, expressed as the cyclic duration factor (c.d.f.) is the ratio of
running time to running time + period of rest
Formula:
c.d.f. % =
running time x 100%
running time + period of rest
The duty rate is limited by the permissible degree of heat in the lifting motor.
The running time is dependent on the necessary lifting height, lifting speed of the electric chain hoist and the number
of lifting motions required for a particular transport procedure (unloading trucks, feeding machines).
It is difficult in practice to take note of the duty rate during the lifting operation. We, therefore, give the following
practical guidelines:
8.1
Short time duty
This duty type is not permissible for the slower speed of hoisting motors with two speeds. After having reached the
maximum running time a break is required and the hoist can be further used in intermittent duty mode.
The permissible operating periods without cooling interval when operation starts and with a motor temperature of
approx. 20° C are following:
Duty group
acc. to FEM 9.511
Duty group
acc. to ISO 4301
Duty rate
c.d.f.
Operating period *
acc. to FEM 9.683 (t
B
in min)
1 Bm M 3 25 % 15
1 Am M 4 30 % 15
2 m M 5 40 % 30
3 m M 6 50 % 30
3 m M 6 60 % 60
* The operating periods t
B
of the STAGEKET chain hoists are higher than required acc. to FEM 9.683.
Table 14: Duty rate for short time duty
running time
lifting
period of rest
running time
lowering
period of rest
1 lifting cycle
s [m]
t [min]