Knowledge of Lifting Electromagnets 

First ，  Application 

  ◆Used for lifting steel and other permeable materials in metallurgy, mining, machinery, transportation and other industries.

  ◆Used as an electromagnetic manipulator to clamp steel permeable materials.

Second, Basic principles and conditions of use

1.Basic Working Principles :

   Power and control equipment supply direct current to the electromagnet. A strong magnetic field is generated inside the electromagnet, and a powerful magnetic force is produced. The magnetic force is transmitted through the shell magnetic circuit and working air gap, achieving the purpose of moving materials.

2.Conditions of use

◆The altitude of the place of use should not exceed 2000 meters;

◆The surrounding medium temperature should range from - 20 °C to +60 °C;

◆The surrounding work environment should be free of hazardous and non-corrosive gases;

◆The relative humidity of the ambient air should not be more than 85% (at 20 °C);

◆Suitable for both indoor and outdoor use.

Third,The main features

1.It has a fully sealed structure, which is moisture resistant.

2.With computer optimization design, it has a rational structure, light weight, strong suction force, and low energy consumption. The excitation coil is treated with a special process to improve the electrical and mechanical properties of the coil. The insulation material of the coil has a heat-resistant grade of C-class, and the overall insulation of the sucker is of H-class, ensuring a long service life.

3.The rated power sustained rate of the common type electromagnet has been increased from 50% in the past to 60%, which improves the usage efficiency of the electromagnet.

4. The high-temperature type electromagnet has unique insulation. The temperature of the suction surface has been increased from 600 °C in the past to 700 °C, expanding the applicable scope of the electromagnet.

5.Installation, operation, and maintenance are simple.

Fourth,The main structure

◆The magnetic circuit of the lifting electromagnet is constituted by the bell cover, inside and outside poles, core and sucked matter.

◆The coil is placed in the bell cover, and together with the non-magnetic protective plate, it forms a sealed container, and is filled with #168 fixed insulating oil.

◆The overall structure uses welded structures.

◆The MW22 and MW42 adopt the wire package structure.

◆The MW92 series pole consists of two parts: the fixed magnetic pole and the movable magnetic pole.

◆The high-temperature electromagnet uses a double radiant special insulation structure.

Fifth,Installation and Commissioning

◆Unpack the box, check the packing list and inventory the random technical documents, and carefully read the relevant documents.

◆According to the specific requirements, determine or select the lifting beam and carry out the installation.

◆Check the electrical performance of the solenoid (coil resistance and insulation resistance), dimensions, the supporting spreader strength and size. If there is no problem, the electromagnet can be installed.  

◆Check that the power output of the matching control device and the parameters of the cable reel equipment shall conform to the requirements of the electromagnet.

◆Connect the cable of the cable reel and the cable connector of the solenoid, turn on the power, and make the electromagnet run for a trial period of 0.5 - 1h. If there is no abnormal phenomenon, it can be put into normal use.

Sixth, Use Precautions 

1.Before use, the cold insulation resistance of the electromagnet at room temperature should be measured, and its value should not be less than 0.5MΩ.

2.If the surface of the object to be adsorbed by the electromagnet is uneven, do not energize the electromagnet before operation. Using a hammer to strike the electromagnet is strictly prohibited.

3.When using the electromagnet for lifting, do not cut sprues and scraps. Especially for large electromagnets, sucking materials with a weight much heavier than the rated suction capacity of the electromagnet, or cutting heads or scraps, may easily damage the bottom of the radiation panel. 

4.The electromagnet should be placed as symmetrically as possible on the center of gravity of the load.

（1）The self-weight of the electromagnet = the rated suction capacity × (1 + eccentricity / pitch). Therefore, the spacing between the lifting electromagnets is preferably slightly larger. When the spacing between two electromagnets is small and the eccentricity is large, it is extremely unsafe to work with an electromagnet having the same self-weight. In the case of an expanded spacing, the amount of eccentricity should be minimized to ensure safety and reliability.

（2）For longer steel materials that are not easy to produce eccentricity, the weight of the electromagnet is generally larger. In this case, the flatness of the adsorption surface is very important, and the two-layer beam hanger should be balanced. Except for special reasons, the combined use of four electromagnets is much less, and it is easy to debug and use in practice, similar to the precision requirements of chain hoists.

（3）When more than four sets of electromagnets are combined for lifting, the electromagnetic adsorption surface should be carefully adjusted according to the actual situation. Otherwise, it will occur that some individual electromagnets not only do not work effectively but also increase the burden on other electromagnets.

5.Both the associated pitch should be half of the length of the material.

6.High-temperature materials need to be lifted with a high-temperature electromagnet, and room-temperature materials should be lifted with a room-temperature electromagnet. Do not use a room-temperature electromagnet to lift high-temperature materials.

7.Do not stay near the electromagnet when waiting for the hot object. Do not work near the electromagnet until the temperature of the high-temperature object drops below 600 °C. For an ultra-high temperature electromagnet, do not work near it until the temperature of the object being sucked by the electromagnet drops below 700 °C.

8.When the electromagnet is not in use, do not let it be stored in the high-temperature zone for a long time.

9.The contact time between the electromagnet and the high-temperature object should be as short as possible.

10.A low power electromagnet cannot be used at a high power level . The corresponding power must be selected according to the specific situation of the electromagnet.

11.For an ultra-high temperature electromagnet, during the using process, if the suction force decreases or the poles overheat, you should let the electromagnet rest for a while, or soak the electromagnet poles in a ditch with a depth of 300mm for cooling.

12.When lifting with the electromagnet using a crane, avoid smashing and pulling off the cable.

13.During operation, periodically observe the voltage and current indication values on the control screen of the electromagnet. The excitation current of the electromagnet should be between the cold current and the thermal current. The allowable error of the voltage does not exceed ± 10%.

14.The electromagnet should be kept dry. After use, it should be stored in a dry, ventilated place free of harmful substances.

15.Regularly check the wear of the chain and the pin.

Selection Considerations

1. If the temperature of the sucked and transported material is below 100 °C, please use the normal-temperature type. If it is over 100 °C, please choose the high-temperature type.

2. If the power sustained rate is more than 60%, use the high-frequency type.

3. For lifting materials in water, please use the diving type (diving depth: 100m). The parameters of the submersible electromagnet are similar to those of the normal-temperature electromagnet. Therefore, the sample is not listed, and users need to order the diving type when placing an order.

4. Ambient temperature: From -5 °C to 40 °C for normal conditions, and from -5 °C to 80 °C for high-temperature conditions. The altitude should not exceed 2000m.

5. Ancillary equipment: The power (current) of the rectifier control equipment should be greater than or equal to that of a single electromagnet or the combined power (current) of multiple electromagnets in the cold state.

 

 

 

Installation Precautions for Suspended Electromagnetic (Permanent Magnetic) Separator ：

 Installation location selection

◆The space should be spacious to facilitate the mobilization and hoisting of the iron remover(magnetic separator).

◆ It should be convenient for the iron remover(magnetic separator) to discharge and remove iron.

◆ It should be conducive to the installation and fixation of the track.

◆It is preferably installed above the throwing point of the driving drum at the head of the conveyor or above the transition idler close to the driving drum.

Suspension methods:
The suspension installation methods are divided into two types: inclined and horizontal, both of which are related to the positioning of the iron remover(magnetic separator) at a certain position on the conveyor belt to work.
Inclined installation:
◆When installed above the head of the conveyor belt for iron removal, the belt - type iron remover(magnetic separator) must be installed longitudinally at an inclination.The main drive drum of the iron remover(magnetic separator) is at a lower position. 倾角a=15°～30°，S=R+300  The inclination angle a = 15° - 30°, and S = R + 300.

◆When installed within the uphill or downhill section of the conveyor belt for iron removal, the belt - type iron remover(magnetic separator) must be hung vertically in the longitudinal direction with respect to the direction of the conveyor belt. It is allowed to be installed with a transverse inclination. The inclination angle a is the same as the uphill or downhill inclination angle of the main belt, but amax < 18°.

                                                                      

                                                         
Horizontal installation:
Except for the uphill and downhill sections, the large conveying belt mostly runs horizontally. The magnetic separator can be hoisted horizontally above any horizontal section of the large belt.

                                                    

Selection of Suspension Tracks:

Number of Tracks:  For heavy - duty magnetic separators, double - track suspension is preferred.

For light - duty magnetic separators or those with only three suspension points, single - track suspension is commonly used.
Track Direction:  

Depending on the site conditions, when the magnetic separator is suspended above the head of the large belt, the track can be perpendicular or parallel to the direction of the large belt.

If the magnetic separator is suspended above the uphill/downhill or horizontal section of the large belt, the track direction must be perpendicular to the direction of the large belt.
Track Model:

Follow the requirements of "Selection of Traveling Devices and Tracks for Suspended Magnetic Separators" (or follow the instructions in the manual).

Selection of Traveling Devices:
◆For belt - type magnetic separators (including permanent - magnet and electromagnetic types), manual or traveling trolleys are generally selected. For heavy - duty belt - type magnetic separators, a double - track manual combined traveling frame is preferred.

 For light - duty belt - type magnetic separators, a single - track combined traveling frame or single - track single - trolley suspension is usually chosen

◆For non - belt - type electromagnetic magnetic separators: An electric traveling trolley must be selected to enable automatic iron - absorption and iron - discarding through electrical control.

For light - duty magnetic separators, especially those with three suspension points, electric single - track single - trolley suspension is generally chosen.

For heavy - duty magnetic separators with four suspension points, an electric double - track or single - track combined traveling frame can be selected.

For heavy - duty magnetic separators with three suspension points, an electric single - track combined traveling frame can be chosen.

Installation Tips:

◆ When installing the equipment in an inclined manner above the head of the large belt, it is advisable that the driving drum of the large belt be made of non - magnetic materials.

◆If it is suspended and installed at other positions, it is recommended to replace the upper flat idler or the 10° or 20° transition idler below the magnetic separator and the large belt with non - magnetic ones.