Electronically commutated motor

DETAILED DESCRIPTION The electronically commutated motor 110 according to FIG.
1 has two stator winding phases 112, 114 and a (schematically illustrated) permanent magnet rotor 116, in whose vicinity a Hall generator 118 is located, as also shown on the left side of FIG.
1.
Respective ohmic resistances of the windings 112 and 114 are designated 120 and 122.
As shown in FIG.
8, by way of example, the two phases 112, 114 are preferably coupled with each other by making the winding with two parallel wires, i.
e.
as a so-called "bifilar" winding.
The terminals of phase 112 are designated a and e, and the terminals of phase 114 are designated a' and b' as shown in FIGS.
8 and 9.
In phase 112, current flows from a to e, while in phase 114, current flows from e' to a', so that these two phases create opposing magnetic fluxes.
Motor 110 can, for example, be constructed as shown in DE 23 46 380 filed Sep.
14 1973, assigned Papst Motoren KG.
Alternatively, phases 112, 114 may be inductively coupled together via the metal lamination stack of the stator.
FIG.
9 shows this, on a two-pole stator 210 of an external rotor motor.
Phase 112 is wound on the upper stator pole 214, and phase 114 is wound on the lower stator pole 216.
Part 218 of the lamination stack between poles 214, 216 effects a close magnetic coupling of the winding phases 112, 114.
The preferred rotation direction of the motor of FIG.
9 is designated 220.
In FIG.
9, the internal stator 210 remains still, and the two-pole rotor 116 rotates around it.
Phase 112 is, as shown in FIG.
1, in series with an npn Darlington transistor 124 with built-in recovery or free-running diode 126, and phase 114 is in series with an npn Darlington transistor 128 with built-in recovery or free-running diode 130.
The emitters of transistors 124, 128 are, in the illustrated embodiment, connected in an advantageous manner via a common emitter resistor 132 to a negative conductor 134.
optionally, each of transistors 124, 128 can have its own emitter resistor.
Phases 112, 114 are, as shown, connected to a positive conductor 136