Magnetic Lifting Machine

Used Tools:

Definition

A lifting machine (figure 1) is a magnetized set of steel components that act as electromagnets to lift large metallic objects such as scrap metal or steel plates. Permanent Magnetic Lifters are mainly used to lift steel plates, blocks, press mold etc. and load / unload in machines during handling operation. They can hoist moving iron blocks and other magnetic materials. They are easy to operate and safe to handle and hence are widely used as lifting devices in factories, docks, warehouses and transportation industries. By using them, working condition can be improved and working efficiency can be increased.

Magnetic Lifting Machine

Figure 1 - Magnetic Lifting Machine Description

This example consists of a magnetostatic analysis of a lifting machine (Figure 2) composed of magnetized steel lifting, a steel plate and a small distance from the electromagnet. The machine is magnetized using a wound coil with a current excitation. EMS from EMWorks has been used to compute the magnetic flux in the machine, as well as the force applied on the steel plate.

Figure 2 - 3D Model of the Magnetic Lifting Machine

Study

The Magnetostatic module of EMS is used to compute and visualize the magnetic flux and the magnetic intensity in the coil, in the steel lifting, in the steel plate and in the air gap between them. It is also used to calculate the inductance of the coil and the electromagnetic force applied in the load (the steel plate). Each stranded coil is made of 5*6000 A-turns.

Materials

For the Magnetostatic study the main property we need is the relative permeability of each material (Table 1).

Table1 - Table of materials

Components / Bodies	Material	Relative Permeability
Coil 1	Copper	0.99991
Coil 2	Copper	0.99991
Air Box	Air	1
Core 1	AISI 1008 Steel	Non linear
Core 2	AISI 1008 Steel	Non linear
Cover 1	AISI 1008 Steel	Non linear
Load	Typical Steel	Non linear
Central Plate 1	AISI 1008 Steel	Non linear
Central Plate 2	AISI 1008 Steel	Non linear
lateral Plate 1	AISI 1008 Steel	Non linear
lateral Plate 2	AISI 1008 Steel	Non linear
Cote 1	AISI 1008 Steel	Non linear
Cote 2	AISI 1008 Steel	Non linear

Results

Fringe and vector plots of the magnetic field are obtained and plotted in Figures 3) and 4), respectively. The magnetic flux reaches values higher than 1.8T at the electromagnets cores while it is around 1.2-1.4T in the load steel. Cross section view of the vector plot is shown in Figure 5.

Figure 3 - Magnetic Flux Density fringe plot

Figure 4 - Magnetic Flux Density vector plot

Figure 5 - Cross section view of the vector magnetic field plot

The generated force by the magnetic lifting device at the load is around 1.14e+5N.

Conclusion

The Magnetostatic module of EMS gives all needed results of a Magnetic Lifting Machine for a good dimensioning and better efficiency. EMS is, an addition of being fully integrated in Solidworks and Autodesk Inventor, accurate, intuitive and easy to use.