AS4827 Electro Holding Magnet for Industrial Lifting
Product Description
How does the Electro Holding Magnet work?
The science behind the working of an electro holding magnet is based on the science of electromagnetism. When an electric current flows through this magnet, it generates a magnetic field.
Making a Magnetic Circuit: The main component of this magnet is a coil of copper wire that is wound around a very porous iron core. When a direct current (DC) voltage, say 12V or 24V, is connected across this coil, it generates a very powerful electromagnetic field.
The magnetic flux passes through the iron core of the magnet, a small air gap, and then through the ferromagnetic object (like a steel plate), and finally through the outer casing of the magnet and then back.
Holding Force Generation: The magnetic force is strongest at the points of contact between the object and the magnet's poles (at its center and outer ring). This is what holds the object firmly in place. The force is at a right angle with respect to its attracting surface.
Control of Actuation: The force is in place as long as the magnet is on. When you switch it off, it releases its grip on the object. To release the electro-permanent magnet, a pulse of electrical current is used to cancel out the magnet of a permanent magnet that is housed internally.
Product detail diagram
How to Choose the Electro Holding Magnet?
To choose the correct electro holding magnet, you should carefully examine the mechanical, electrical, and environmental demands of your application.
Step 1: Determine the amount of holding force you require
To begin with, you should determine the amount of holding force you require to securely hold your object in place. It is recommended that you apply a safety factor that is at least 2 to 4 times the weight you estimated, particularly in applications that experience vibration or side loads. It should be kept in mind that the real force will be less if the surface of contact is rough, dirty, or thin.
Step 2: Examine the workpiece and interface.
The workpiece must be ferromagnetic, such as mild steel. It is recommended that you use an armature plate if it is not ferromagnetic, too thin, or has a fragile surface.
The surface must be as clean and flat as possible. Any non-magnetic coatings, such as paint or plating, must be taken into account because they will create an air gap that will reduce the holding force.
Step 3: Determine the electrical and operation settings
Power Supply: Determine what magnet you can use with the voltage you have (e.g., 24V DC).
Duty Cycle: Will it be on for a brief time or forever? To avoid overheating, select a magnet with a 100% rating
Control Type: Determine if you need a simple on/off switch or a more complicated controller, especially for electro-permanent magnets.
Step 4: Consider the environment and physical space
Determine the IP rating you need for dust and water resistance.
Physical Space: Ensure you have sufficient space for the magnet, measuring the space available to guarantee sufficient diameter and length for the magnet. Consider the location of mounting threads.
Residual Release: If you're working with thin objects, you might want to use a model with a mechanical ejector pin for removing residual magnetism.
FAQ OF Electro Holding Magnet
Q1: What is the difference between an "electromagnet" and an "electro-permanent" magnet?
A: The difference between the two is that, in the case of a regular "energize-to-hold" electromagnet, the permanent holding force is supplied by the electricity. The permanent holding force is supplied by permanent magnets in the case of an "electro-permanent" or "energize-to-release" magnet. A pulse of electricity is used to release the held object.
Q2: What happens to my "electromagnet" if the electricity is switched off while I am holding something?
A: If you turn off your "energize-to-hold" magnet, the held object will immediately be released. The "energise-to-release" or "electro-permanent" magnet is the safest to use in case of a power failure, as the held object will remain in place even in the absence of any electricity.
Q3: Will my "electro holding magnet" hold non-ferrous metals such as aluminum and brass?
A: No, electro holding magnets are only able to attract ferromagnetic materials like iron and steel. They cannot be used to attract non-ferrous materials like aluminum, brass, copper, and stainless steel.
Q4: Why isn't my magnet as strong as it should be according to the data sheet?
A: The forces on the data sheet are calculated when the magnet face is fully covered with thick material of mild steel. The presence of an air gap between the magnet and object (paint, etc.), thin material of object (magnetic saturation), poor quality of material (hardened tool steel), and partial coverage of magnet pole will reduce your actual holding force compared to the rated force on the data sheet.
Q5: What is "residual magnetism" and how is it handled?
A: Residual magnetism is a small magnetic force that is present after the magnet is turned off and is still able to attract small objects. You could use a magnet with a spring-loaded ejector pin to prevent residual magnetism from occurring, or you could send a reverse current pulse through the magnet core and tell your control circuit to demagnetize it.
Q6: Is it possible to operate an electro holding magnet continuously?
A: Yes, many of them are rated for continuous operation as shown by a 100% duty cycle rating ED. However, when running continuously, the magnet will get hot. You should ensure that the application temperature is within the insulation class of your magnet.
Q7: What is an armature plate and do I need one?
A: An armature plate is a disc of mild steel that is machined to a precise shape and is attached to your workpiece. It is a perfect flat magnetizing surface. You will need one if your workpiece is thin, rough, non-ferrous, or coated and might produce an air gap.
Q8: What are the different voltage options?
A: The most common voltages used in industrial DC powered holding magnets are 12V DC and 24V DC, but some manufacturers may offer 240V AC with an inbuilt rectifier or other voltages on request.