Datasheet

28
Draw a line from the point on the left-hand scale indicating the
required number of operating cycles to the point on the right
hand scale indicating the required number of operating cycles per
hour. Then, from the point where this line intersects with the
centre axis, draw a horizontal line to the left or right scale for the
actual number of daily operating hours.
Note: If a figure of 365 days per annum is being employed instead
of 250, the total operating time obtained from the nomogram
must be multiplied by 0.68.
Example:
Service requirements: 1.4 million operating cycles endurance,
200 operating cycles per hour, 16 hours service per day.
Result:
Total operating time approx =18 months.
Accessories and ordering data:
AC Coils:
Spare coils for Type
1)
Std. pkg. (nos.)
3TF50 00 0A.. 3TY7 503-0A ..0-0H
3TF52 00 0A.. 3TY7 523-0A ..0-0H
1
3TF54 00 0A.. 3TY7 543-0A ..0-0H
3TF56 00 0A.. 3TY7 563-0A ..0-0H
1)
Coil voltage code AC 50Hz:
Coil voltage 110 230 415
Code F0 P0 R0
(Other coil voltages are also available)
Spares and ordering data
Contact kits:
Spare contact kit for Type Std. pkg. (nos.)
3TF50 00 0A.. 3TY7 500-0ZA
3TF52 00 0A.. 3TY7 520-0ZA
1
3TF54 00 0A.. 3TY7 540-0ZA
3TF56 00 0A.. 3TY7 560-0ZA
Dimensional drawing
The “Hoisting Duty” Contactors are mechanically similar to our
existing 3TF power contactors. Therefore they have exactly same
dimensions as the corresponding 3TF power contactors.
Please refer page nos. 21 and 22.
Useful technical information
Starting method of Slip ring motor (AC2 duty):
Three types of the contactors are used to control the three
phase slip-ring motors: the stator contactor, the acceleration
contactor and the rotor short circuit contactor.
Stator contactor
Initially the stator contactor (K1) is closed to energize the motor.
None of the rotor contactor (K2 or K3) is closed yet. Hence all the
resistances are present in the rotor circuit. The starting current
can reach to 1.5 to 4 times of the rated operational current. The
AC2 rating of the stator contactor is selected as per the load factor
of the motor.
Load factor =
on time *100
Cycle time (on time + rest time)
Acceleration contactor
Now acceleration contactor (K2) is closed which short circuits the
resistances (R1). The sizing of this contactor (K2) is as per AC1
rated operational current. The current flow time per cycle and the
number of cycles per hour has to be considered for the selection.
Rotor short circuit contactor
At the end, the rotor short circuit contactor (K3) closes, short
circuiting the last resistance bank (R2) thus remove all the
resistances from the rotor circuit. The starting period is hence
completed. The duty of this contactors is characterized by the
small closing stress. the decisive factor is the thermal stress. The
duty factor is considered while finding out the permissible values
of the rated operational rotor current for rotor contactors.
Picture below shows the acceleration (K2) and the rotor short
circuiting contactor (K3) in the delta connection. If they are
connected in star then the ratings are reduced by 35%.