Datasheet

27
Fig. 2 Contact endurance for mixed operation as a function of motor rated
current. Motor on rated load, inching at 2.5 times motor rated current
(slipring motor).
The contact endurance as a function of the motor rated current
with mixed operation can be determined from Fig. 2 for
proportions of inching of 0, 10, 20, 50 and 100%. The values
obtained are only applicable if rated motor load is used
continuously. In practice therefore, the contact endurance should
be greater.
Example 1
Motor rated current 150A. Selected contactor: 3TF5600
Contact endurance in operating cycles at 400V With inching of
0% 10% 20% 50% 100%
5.4 x 106 4.6 x 106 3.9 x 106 2.3 x 106 1.4 x 106
Example 2
Maximum permitted motor rated current for a contact endurance
of 2,000,000 operating cycles at 400V.
Stator Permitted rated current of slipring motor
contactor with inching
Type 10% 20% 50% 100%
approx. approx. approx. approx.
AAAA
3TF50 00 75 68 48 33
3TF52 00 110 95 66 48
3TF54 00 175 160 125 80
3TF56 00 240 230 160 120
D. NOMOGREM
Apart from knowing the figure for contact endurance in operating cycles, users are also interested to know what period of time this
amounts to before the contacts have to be changed. The value can be ascertained from the nomogram in Fig. 3. using the Nomogram
Fig. 3 Nomogram for determining contact endurance in year (250 working days) and months with daily operating hours of 4, 8, 12, 16, 20 and 24 h.