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- Synkroniset moottorit
- Induktiomoottorit
- Tasavirtamoottorit
- Harjattomat tasavirtamoottorit
- Askelmoottorit
- Reluktanssimoottorit ja moottorit, joiden roottorin magneettiset ominaisuudet eivät ole ympyräsymmetrisiä
Luokissa 1, 2, 4 ja 5 tehdään tyypillisesti moottorin paikallaan pysyvään runkoon eli staattoriin pyörivä magneettikenttä, jota eri tavoin magnetoitu akselia pyörittävä osa eli roottori seuraa. Luokassa 3 staattori on vakiomagnetoitu ja roottorin magnetointia muutetaan sen pyöriessä siten, että sen magneettikenttä on aina kohtisuorassa staattorin magneettikenttään nähden.
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Katso: How Stepper Motor Works - 2
Synchronous 3-phase reluctance and salient pole motors
The field winding in a round rotor (left) and salient rotor (right) are compared in the Figure below according to Nasar /9/.
Figure: The field winding in a round rotor (left) and salient rotor (right).
The torque of a reluctance motor is calculated with the cross field principle:
Here we have:
With some trigonometry the torque becomes:
The torque is represented in the Figure below as the function of the pole angle δ. The diameter of the circle is D = |imd-imq| which is considered here to be a constant. The torque is ½ΨD·sin2δ.
Figure: The diameter of the circle is D = |imd-imq| which is considered here to be a constant. The torque is proportional to ½D·sin2δ.
If we have a salient pole motor, it generates the sum moment which is the sum of the electromagnetic and reluctance moment, as shown in the Figure below.
Figure.
The analysis is done now be noticing that the magnetising current is (if rotor current iR = 0, we have the reluctance motor):
The generation of the torque is show in the Figure below.
Figure:
The diameter of the circle is D = |imd-imq| which is considered here to be a constant.
The reluctance torque is proportional to ½D·sin2δ,
and the electromagnetic torque is, as usual, proportional to iR·sinδ.
The total torque is proportional to the T* shown in the figure.