Manual
20 www.powerjacks.com
Operation5
5.2.28 Connecting Screw Jacks in Series
The number of screw jacks that can be connected in series is limited by input torque
requirements on the rst worm shaft in the line. For the E-Series the torque on the worm shaft
of the rst screw jack should not exceed 300% of its rated full load torque (this does not include
the 200kN screw jacks which are rated at 200%).
5.2.29 Efciency of a Multiple Screw Jack System
In addition to individual device efciencies, the efciency of the screw jack arrangement must
be taken into consideration. The arrangement efciency allows for misalignment due to slight
deformation of the structure under load, for the losses in couplings, bearings, and for a normal
amount of misalignment in positioning the screw jacks and gearboxes. For efciency values
consult Power Jacks product literature or engineers.
5.2.30 Screw Jack Fitted with 3rd Party Accessories
If your screw jack is tted with a device not manufactured by Power Jacks then please consult
the provided manual for this device.