Motive of permanent magnetism dc is by together or the dc motive that many permanent magnet builds magnetic field, its function and constant motive of dc of his of excitation electric current encourage is similar, can come by change armature voltage conveniently timing. With him photograph of motive of encourage type dc is compared, have volume small, efficiency tall, structure the simple, quantity that use copper is little wait for an advantage, it is the main type of small-power dc motive.

The magnetically hard material that uses according to place is different, cent of motive of permanent magnetism dc is aluminous nickel cobalt motive of dc of motive of dc of permanent magnetism of motive of permanent magnetism dc, ferrite and rare earth permanent magnetism. Motive of dc of aluminous nickel cobaltic permanent magnetism needs to spend many precious heavy metal, price taller, but good to the adaptability of high temperature, use at environmental temperature taller or taller to the temperature stability demand of electromotor circumstance. Motive of dc of ferrite permanent magnetism with cheap be good at, and performance is good, use extensively at the domain such as electric home appliances

One, the general principle that chooses motive of permanent magnetism dc:

(1) the choice of the type

Appropriate is preferential choose efficiency the motive of dc of ferrite permanent magnetism with tall, low-cost, small temperature rise. When strict to performance demand, bulk only the ability when temperature of small, environment is higher considers to choose motive of dc of motive of dc of aluminous nickel cobaltic permanent magnetism or rare earth permanent magnetism.

(2) the power of logical choice electromotor

Electromotor outputs most high-power has limit, if the power choice of electromotor is too little, load exceeded the rated output power of electromotor to be able to produce electromotor overload, electromotor can appear when overload calorific, oscillatory, rotate speed drops, sound is unusual wait for a phenomenon, when serious overload, will burn down electromotor. And power is too great, can create economic waste. Because this is reasonable,the power of choice electromotor is very important.
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