6.3KW Slip Ring

The Towerbase

Climbing the platform with stairs. Standing next to one of the 6.3KW Slip Ring Induction Motor with reductor in oil bath system.



Slip Ring Motor

The stator coil is exactly the same as a 3 phase induction motor. The difference being the rotar which has 3 phase wiring in star point or delta connection and also has the sliprings connected to the wiring of the rotor. Brushes are use for the contact between the surpply and the rotor. By controling the current we can control the torgue and speed of the motor. This is done with resistance. Resistance can be greated by means of a resistance bank, liquid resistance or a variable resistance.


The basic Idee

The higher the resistance, low starting current, high torque, high % slip. Motor runs slowly. Thus by varing the rotor resistance the motor can be adapted for a spesific load.

Lieberr 120HC tower crane SA-motor
SGF 631/4 AAA, 6,3 KW, 1420 U/Min
partnr# 610011401

  Wound rotor induction motors

Placing resistance in series with the rotor windings not only decreases start current, but also increases the starting torque.

Brake assembly

brake caliper is the assembly which houses the brake pads and pistons. Common caliper design uses a single hydraulically actuated piston within a cylinder. Brake pads are visible embedded in the disc.

All has been removed, cause an HF antenna does not require a brake due to this high gearbox delay.



Old junk from birds...


Slip Rings

Former used for 400VAC and control to the tower crane. unfasten the bolds and removing the heavy weight stand off.


Stand off

Using my forklift to remove...



slip rings removed from the base unit. This item could be used for future projects



Making some room for heavy equipment which dig out the 16m3 hole

Disentomb the shrubs to a news location.This part of our hobby is usually underexposed....