| 摘要 |
The single-phase asynchronous motor which is equipped with a multislotted armature is insensitive to the opposing rotating field, and the three-phase motor is insensitive to the asymmetry of the mains voltage. Investigations into the two armature types revealed that the single-turn, squirrel-cage armature could be replaced by a squirrel-cage armature having two rows of slots, a magnetic link having been formed between the upper and lower slots. The production costs were smaller but still too high. Not until the further investigations was it found that the opposing rotating field could be counteracted by means of a relationship, determined in the armature, between the resistance and the inductance. Since, for previous motors of approximately 2.2 kW, the number of slots in the armature is approximately 20 for 2 poles and approximately 28 slots for 4 poles, the ratio of the resistance and inductance is favourable for the opposing rotating field, the opposing rotating field does not become ineffective until the number of slots in the armature has been increased to 25-30 for 2 poles and 40-50 for 4 poles. When selecting the precise number of slots, the fact that there is no double saddle in the starting characteristic must be taken into account.
|
