Teach yourself to judge machine of Electromechanical of permanent magnetism pneumatics whether demagnetization?
In recent years, machine of pneumatics of screw of permanent magnetism frequency conversion because its the characteristic such as stability of efficient, energy-saving, pressure gets the reliance of increasing client. But company of production of electric machinery of the permanent magnetism on market is uneven, if the choice is undeserved, bring about permanent magnetism electric machinery likely to break the risk of magnetism, and once permanent magnetism electric machinery breaks magnetism, basically can choose to change only electric machinery, bring about maintenance thereby cost is big. So, whether to judge permanent magnetism electric machinery to break magnetism?
1. The electric current when the machine is beginning to move is normal, be in those who pass period of time hind, electric current greatens, time is long, can sign up for transducer overload. Need type selecting of transducer of manufacturer of affirmatory pneumatics aircraft to not have above all by accident, whether has been the parameter inside cross-check transducer altered. If both does not have a problem, need to undertake judging through opposing electromotive force, nose and electric machinery come away, undertake carrying for nothing differentiating, empty running comes rated frequency, the voltage that outputs right now opposes electromotive force namely, if go up under electric machinery nameplate,turn over above of electromotive force 50V, can decide electric machinery demagnetization.
2. Electric current moves to be able to exceed rating commonly after demagnetization of permanent magnetism electric machinery more, those are in only low speed or high speed runs ability to sign up for overload or now and then the situation that signs up for overload is general either demagnetization is brought about.
3. Demagnetization of permanent magnetism electric machinery needs proper time, a few some months even 9 years, if mistake of manufacturer type selecting brings about overload of newspaper electric current, do not belong to electric machinery demagnetization.
4. Reason of electric machinery demagnetization
Of ① electric machinery medicinal powder sirocco fan is unusual, bring about electric machinery high temperature
② electric machinery did not install temperature protector
③ environment temperature is exorbitant
Design of ④ electric machinery is unreasonable
Prevent the 1st action: Choose power of permanent magnetism electric machinery correctly
The power of demagnetization and permanent magnetism electric machinery chooses to concern. The power that chooses permanent magnetism electric machinery correctly can prevent or defer demagnetization. The main reason of demagnetization of electric machinery of permanent magnetism synchronism is it is temperature exorbitant, overload is the main reason with exorbitant temperature. Accordingly, want to leave the surplus with have certain when choosing power of permanent magnetism electric machinery, according to laden actual condition, general 20% the left and right sides is more appropriate.
Prevent the 2nd action: Avoid to burden starts and start often
Basket model electric machinery of permanent magnetism of asynchronous starting synchronism avoids burden to start directly as far as possible or start often. In asynchronous starting process, starting torsion is oscillation, in starting torsion trough paragraph, stator magnetic field is demagnetization action to rotor magnetic pole. Because this avoids asynchronous permanent magnetism as far as possible,electric machinery burden mixes synchronism to start often.
Prevent the 3rd action: Improve a design
A. Proper addition the ply of permanent magnet
From the point of view that electric machinery designs permanent magnetism synchronism and makes, should consider torsion of armature reaction, electromagnetism and permanent magnet demagnetization 3 person the relation between. Of the magnetic flux that arises in torsion winding electric current and the magnetic flux that radial load winding produces fall in action jointly, rotor surface permanent magnet causes demagnetization easily. In electromotor air gap changeless circumstance falls, should assure permanent magnet not demagnetization, most effective method increases the ply of permanent magnet appropriately namely.
B. Rotor interior has ventilated chamfer return, reduce rotor temperature rise
The main factor that affects reliability of permanent magnetism electric machinery is permanent magnet demagnetization. Rotor temperature rise is exorbitant, permanent magnet will produce what cannot go against to break magnetism. When the structure is designed, can design rotor interior ventilated loop, direct cooling magnet steel. Dropped magnet steel temperature not only, also improved efficiency.