| 摘要 |
<p>Windings 24A, 24B ... produce a varying back emf as the rotor rotates causing a corresponding variation in motor current at a frequency dependent on the number of windings. One of the windings is wound with for example fewer turns so as to superimpose a cyclic variation on the back emf related to angular rotor position. This is detected and used to count the number of revolutions of the motor in a vehicle window winding arrangement so as to determine the fully closed/open positions. Alternatively, a resistor may be connected across the windings or the winding spacing may be varied.</p> |
