SICOP Contactors For Hoisting Duty
SICOP Contactors For Hoisting Duty
SICOP Contactors For Hoisting Duty
Siemens contactors have been performing successfully AC-2 Hoisting operation is the typical duty for starting
over the last 50 years in the most critical applications and switching off fully-loaded slipring motors in the
and in rough conditions. Siemens now introduces for the starting phase, during braking by reversal as well as during
Indian industry special “Hoisting Duty” Contactors for reversing and jogging mode. However, the typical hoisting
crane duty and hoisting applications. These contactors gear mixed operation represents lower stress because
incorporate special features, which make them ideal for switching-off operations in stationary duty and partial
the most demanding switching application. loads occur.
For cranes and similar hoisting equipment, the common
Degree of Protection
practice is to use AC slipring motors. Hence the contactor
used to switch these motors perform AC-2 duty. The contactors comply with degree of protection
[AC-2 operation is the typical duty for starting and switching IP 00 to IEC 947-1 and DIN 40 050.
off fully loaded slipring motors in starting phase.]
Standard Specification
The rating of contactor, to switch these motors, is
The contactors comply with the “Regulations to low
selected primarily on the basis of rated make & break
voltage switchgear” of DIN VDE 0660 and IEC-947-4-1.
capacity and the desired electrical endurance. In case of
hoisting duty, braking current is the starting current and Service Temperature : -25°C to 55°C
frequency of switching is high.
“SICOP” Range of Power contactors are extensively used Features
for hoisting and other critical applications. In this series These new “Hoisting Duty” Contactors are mechanically
we have now introduced new 3TF50/52/54/56 similar to our existing 3TF contactors.
“Hoisting Duty Contactors” which have high electrical
and mechanical endurance. The electrical endurance In addition to this, they are electrically superior in taking
depends on the type of operation, the amount of inching care of excessive stresses coming on contactors during
involved and the current interruption by contacts. The their operations in crane applications.
contacts close bounce free and hence the making current “Hoisting Duty “ Contactors are provided with new design
has no effect on the electrical endurance. of contacts resulting in high electrical and mechanical life.
Application Reliability
The use of AC contactors is classified in different utilization The “Hoisting Duty” Contactors have specially treated
categories according to DIN VDE 0660, Part 102. coils which are suitable for high frequency switching and
Three-phase motors with slipring rotors are often used high vibrations. This helps in reducing coil failures.
in hoisting gear operation. Utilization category
AC-2 applies to this application. Benefits
Utilization categories AC-3 and AC-4 apply to the “Hoisting Duty” Contactors offer cost savings by reducing
switching of three-phase squirrel cage motors. down time, less inventory. This offers value for money.
Fig. 1 Contact endurance of 3TF contactors as a function of breaking current when switching resistive and inductive AC loads.
Selection of contactors for contact endurance with normal and inching operation
Contactors suffer more erosion during inching operation Max. permissible current Contact life when Contactor
than when stopping motors from a steady speed, i.e. normal and attainable contact breaking the stator Type
operation. With slipring motors the starting current can be endurance when braking contactor load currents
up to 2.5 times the rated current of the motor which means starting current given for S3-100% duty,
that this current has to be broken when inching is taking below PF ≥ 0.4 (2.5 x Ie) Ic = Ie, no inching
place. During normal operation, on the other hand, only A Opearting cycles A Approx.
the rated current has to be broken under full-load; under Approx. Operating cycles
part-load it is even less. Determining contact endurance 30 280,000 8 2,000,000 3TF31
from AC-2 duty (I c = 2.5 x I e) will only give correct results 55 280,000 13 3,500,000 3TF33
when 100% inching operation is involved. 80 230,000 20 2,800,000 3TF45
112 250,000 30 2,700,000 3TF47
187 250,000 45 2,800,000 3TF49
275 280,000 65 3,500,000 3TF5000
425 250,000 95 3,100,000 3TF5200
625 250,000 160 2,700,000 3TF5400
1000 150,000 250 2,500,000 3TF5600
1575 250,000 400 2,500,000 3TF68
The maximum permitted current (e.g. locked-rotor current of motor)
must not exceed the values given in the “Max. starting current and
attainable contact endurance” column. The values cannot be increased
by paralleling pole assemblies.
Siemens Ltd.
Standard Products Division
LV Controls & Distribution Products
Thane Belapur Road
Thane 400 601
Tel +91 22 7600001
Fax +91 22 7600076
Siemens Ltd. "Product development is a continuous process.
Consequently the data indicated in this folder is
SGR-01-101-063