After one or two years of operation of the electromagnetic dry powder
magnetic separator, many customers have found that the iron removal effect is
not as good as before. When measured with a Gaussian meter, the magnetic field
strength in the sorting area is more than 20% lower than the initial value. The
decrease in magnetic field strength is usually caused by two links: the
excitation coil and the magnetic circuit.
The aging of the excitation coil or inter turn short circuit is the primary
cause of magnetic field decrease. The coil works under high temperature for a
long time, and the insulation layer gradually ages. After a slight short circuit
occurs between turns, the effective number of turns decreases, and the magnetic
field strength decreases accordingly. The inspection method is simple:
disconnect the power supply, measure the DC resistance of the coil with a
multimeter, and compare it with the standard value in the manual. If the
deviation exceeds 10%, it indicates that the coil has aged or short circuited
and needs to be replaced. If the resistance is normal but the magnetic field is
still low, check whether the output current of the excitation power supply has
reached the rated value. Damaged rectifier components can also cause
insufficient current.
Rust on the magnetic yoke or wear on the magnetic medium can also weaken the
magnetic field. The magnetic yoke is a pathway for magnetic field lines. After
rusting, the magnetic permeability decreases and the loss of magnetic field
lines increases during transmission. Open the magnetic shell and check for rust
on the surface of the magnetic yoke. For minor rust, sand it with sandpaper and
apply anti rust paint. For severe rust, replace the magnetic yoke. After the
wear of the magnetic medium (steel mesh or steel rod) becomes finer, the
magnetic field gradient decreases and the adsorption capacity decreases. It is
recommended to replace the magnetic medium every two years.
Poor cooling leads to high coil temperature and magnetic field attenuation.
When the coil temperature exceeds 80 ℃, the magnetic field strength
significantly decreases. Check whether the cooling water circuit is
unobstructed, whether the water temperature is normal, and clean the scale and
impurities in the water circuit. Pay attention to the temperature control
instrument during daily operation, and immediately reduce the load or stop the
machine for heat dissipation when the temperature is too high.
The decrease in magnetic field strength is a gradual process, and by the time
the iron removal effect significantly deteriorates, it often has already
decreased significantly. It is recommended to use a Gaussian meter to test the
magnetic field strength in the sorting area once every quarter, keep records,
and promptly investigate if it continues to decrease. For equipment operation
related issues, please call Manager Zhang at 13583776655 (same as WeChat) at
Shandong Heavy Industry.