FAQ of Magnetic Coupling

The magnetic coupling is a torque-transmitting device that uses a magnetic field rather than a physical-mechanical connection. visit here to know more: magnetic coupling

Magnetic coupling is a simple structure, compared with the fluid coupling and frequency converter. The magnetic coupling has a magnetic circuit and the electromagnetic machine can rotate the rotor by transmitting energy through the magnetic circuit.

Maintenance-free

Thanks to the relatively simple structure of the magnetic coupling transmission device, there is a gap between the active part and the driven part, and the installation, disassembly and maintenance are convenient, which can not only reduce the difficulty and labor intensity of equipment maintenance.

High reliability

As we all know, product failures are mostly caused by wear parts exceeding the limits of normal use. and Magnetic coupling provides a durable, reliable way to connect two devices without any wear or consumable parts. This means that the magnetic coupling is less prone to failure, which can lead to downtime. This also means that there is no need to have hydraulic fluid in stock all year round like a liquid coupling.

Small size

Thanks to the low alignment requirements, the installation of the magnetic coupling is relatively simple. Than means customer no need for a moving foundation to transform the system.

Easy installation,

Thanks to the low alignment requirements, the installation of the magnetic coupling is relatively simple. It can be installed with simple training.

long service life (up to 30 years)

Magneitc coupling has long service (20-30years), that means it has the highest comprehensive cost performance throughout the life cycle.

no additional friction,

no need for lubrication to keep the equipment running at high efficiency.

We need to communicate more with our customers so that we can understand their needs. And make sure what they ask for is exactly what they want.

As a factory, we will have some spot products. But different projects have different requirements for products. For some products, customization is required. In this case, the lead time will be 40-50 days.

Most magnetic couplings are used in these places:

Energy saving needs

High reliability requirements

The environment requires high harmonics or electromagnetic waves

Speed requirement

Harsh environment

Vibration that cannot be ruled out

Pulsed load

Thermal expansion and contraction, not easy to Alignment

Most corporate customers who use magnet couplings have one characteristic: Even brief downtimes can cause significant economic losses. In many cases, the loss caused by downtime in one year is higher than the price of the magnet coupling. For example power plants, steel plants, coal plants, mines. Magnetic couplings are often connected to high-power motors and other equipment, as well as conveyors, bucket wheels, elevators, roller presses, coal mills, mixers, injection molding machines and other equipment.

The structure of the drum type and the pan type （disc） magnetic coupling is completely different, which leads to the completely different application time, structure, safety, heat dissipation principle and heat dissipation effect of the two products. visit there to know more.

Synchronous：

The driving and driven rotors of the synchronous drum magnetic coupling are magnetic rotors, and there is an air gap between the rotors. They were installed on the driving shaft (drive shaft) and the driven shaft (load shaft). The magnetic force between the two sets of magnetic rotors is coupled to each other to transmit torque, and the magnetic suspension space transmission connects the prime mover and the working machine.

Eddy current： The eddy current magnetic coupling is basically composed of a conductor rotor connected to the motor end and a magnetic rotor connected to the reducer end. shaft connection. When the magnetic coupling is running, the conductor rotor is driven by the motor shaft to move relative to the magnetic rotor connected to the reducer end, resulting in slip; thus the conductor rotor cuts the magnetic field lines of the magnetic rotor, and eddy current is generated in the conductor rotor, and the eddy current generates an induced electromagnetic field; the conductor The electromagnetic field induced in the rotor pulls the magnetic rotor to rotate, thereby transmitting torque and rotation.

If you want to know more, please check the post "magnetic coupling principle"

This is a complex question that we cannot answer with simple words. What kind of coupling should be chosen depends on the actual situation of the project. We recommend that you consult a professional engineer, or contact us, we will provide you with professional advice.

Yes. We will professionally handle the shipping process, including any documentation preparation and/or non Dangerous Goods labeling. However, if you plan to re-package or re-ship magnetic materials yourself, please be aware that shipping magnets via air classifies them as non Dangerous Goods and requires proper paperwork and labeling.

1) Magnetic couplings are partially standardized products. At the beginning of the selection of couplings, you should learn about relevant standards and mechanical industry standards. If the coupling cannot find a suitable type, you can contact the magnetic coupling manufacturer to produce your own coupling.

2) The torque of the magnetic coupling should meet the requirements of the power machine of the transmission system. According to the power and speed of the power machine and the working machine, the reasonable torque value of the coupling can be calculated, so as to initially select the power model of the coupling.

3) After the initial selection of the magnetic coupling, the size of the coupling should be determined according to the shaft diameter and shaft hole length of the driving shaft and the driven shaft, and the specification of the coupling should be adjusted. The adjustment of the coupling model should also consider whether the speed between the driving shaft and the driven shaft connected by the coupling is consistent, and whether the shaft diameter is the same.

4) In the selection of magnetic coupling, all factors should be considered comprehensively again to ensure that the size, torque, shaft diameter and shaft hole of the coupling are matched with the motor and reducer, and can adapt to the corresponding working environment. After selecting the model of the coupling, the strength of the shaft key should be checked and calculated, and finally the model of the coupling should be determined.

5) According to the load characteristics driven by the equipment and the soft start characteristics of the magnetic coupling, the selection of the magnetic coupling should be careful. Such as heavy-duty equipment such as elevator load, limestone conveyor belt conveyor, clinker zipper machine, etc., especially in the design department, in order to reduce the installed capacity, the power margin of the drive equipment is small when selecting the model, and it is often unable to start normally with material after the shutdown is encountered. In this case, the torque-limiting magnetic coupling should be used as far as possible when selecting the magnetic coupling, and the power should be one level larger.

6) Use frequency conversion speed regulation equipment, try not to use magnetic coupling, this is because the mechanical characteristics of frequency conversion equipment are soft at low frequency, coupled with the flexible start characteristics of magnetic coupling, it is easy to cause motor stall, resulting in failure to stop the equipment. start again

NdFeB magnetic coupling:-130℃ – 230 ℃

SmCo magnetic coupling: -273 – 250 or 350 ℃

It depends on what magnet the magnetic coupling is using, NdFeB (neodymium magnet) or SmCo (Samarium Cobalt).

NdFeB

It depends on the grades of NdFeB. Different grades have different maximum working temperatures.

Samarium Cobalt

The working temperature can be as high as 350 degrees. If it is not the magnetic coupling applied to the pump, the working temperature is generally 40-50 ℃.  Magnets love the cold, so no need to worry about their performance in the cold environment. One of our couplings operates in temperatures as low as -50°C in an open-pit coal mine.

1) The magnetic coupling supports the rotation of the motor in any direction. Whether it is the first commissioning of equipment for a new enterprise, or the transformation of couplings such as hydraulic couplings during use, in order to avoid damage to the equipment, the motor must be jogged first during the test run, and the test run of the equipment can only be carried out after confirming that its steering is correct. Under normal circumstances, the low-voltage motor is allowed to start twice in the cold state, and the interval between each time shall not be less than 5 minutes, and it is allowed to start once in the hot state; the high-voltage motor is allowed to start once in the hot state, and the time interval shall not be less than 240 minutes, and it is allowed to start 2 times in the cold state, and the interval between each time should not be less than 60 minutes.

2) When using an eddy current magnetic coupling, it is necessary to properly consider that the working temperature cannot be too high because the magnetic coupler uses the principle of eddy current induction. Under normal circumstances, the loss caused by eddy current is released from the magnetic conductor in the form of heat, which causes the temperature of the working environment of the permanent magnet to rise. Therefore, the protective cover of the magnetic coupler at the production site should be well-ventilated to avoid heat accumulation.

3) When using a magnetic coupler, it is necessary to ensure the safety and reliability of various interlocking signals of the host equipment, such as the interlocking protection between the tail wheel speed measurement signal of the hoist and the driving motor, and the interlocking trip protection between the equipment and the upper process equipment. After the overload protection of the magnetic coupler, the host equipment installed with the magnetic coupler will stop running. If the upper-level process equipment cannot be chained to stop, it will cause the elevator to press the material and the feeding slide to block the material.

4) If the load end stops due to overload or equipment failure, and the tail wheel speed detection of the hoist and other equipment happens to be damaged, in this case the motor will run normally, and all or most of the power generated by the eddy current will act on the magnetizer, causing The working temperature of the permanent magnet rises rapidly. When the temperature rises beyond the allowable temperature of the permanent magnet, the magnetic performance will decrease with the increase of this temperature. When the temperature rises to the critical point of permanent magnet failure, the magnetic coupling will "Loss of magnetism" and stop working. Therefore, in production, one is to avoid overloading the equipment as much as possible; the other is to install speed measurement and detection protection devices on the head and tail wheels of the equipment to prevent incidents of equipment damage.

5) From another point of view, in order to avoid the "loss of magnetism" phenomenon of the magnetic coupler, it should be considered to add air guide vanes or air guide holes from the beginning of the design of the equipment. In addition, when the magnetic coupler is overloaded, its The gap opened by the two parts can be designed to be larger, so that the electric conductor will greatly reduce the cutting of the magnetic field lines, and its calorific value will be relatively reduced a lot. In this way, even if the speed measurement detection protection is not in place, it will not damage the equipment and affect the normal production.