Electric motor

Abstract

electric motor, with coil windings inserted in stator slots, the machine is designed with four poles, wherein a first part of the coil windings are assigned to a main strand and the other coil windings to an auxiliary strand, where the number of coil windings of the main strand is in the ratio of five to four to the number of coil windings of the auxiliary strand, characterized by the fact that the auxiliary strand has four groups, the groups being regularly spaced apart from each other in the circumferential direction, each group being formed from two coil windings arranged concentrically to each other, where the main strand - has two first groups, each consisting of three, in particular concentric, coil windings, and - has two second groups, each consisting of two concentric coil windings, where the first and second groups alternate in the circumferential direction, where the main strand occupies five stator slots per pole and the auxiliary strand occupies four stator slots per pole.

Description

[0001] The invention relates to an electric motor.

[0002] It is generally known that in three-phase motors, the stator windings are designed in such a way as to generate a rotating magnetic field. For this purpose, the three-phase motor has three windings, each supplied by one phase of a three-phase power supply network.

[0003] The generic term for the electric motor according to claim 1 is known from DE 19 37 377 A.

[0004] From US 3 321 653 A, a winding of a stator of another three-phase motor is known.

[0005] The invention is therefore based on the objective of using a single-phase voltage supply for generating rotating fields.

[0006] According to the invention, the problem is solved in the case of the electric machine, in particular the electric motor, according to the features specified in claim 1.

[0007] In an advantageous embodiment, the auxiliary winding is connected in series with a capacitor, and the series circuit thus formed is powered by the alternating voltage supplying the main winding, in particular single-phase alternating voltage.

[0008] In an advantageous embodiment, the grooves are regularly spaced apart in the circumferential direction. An advantage of this is that a rotating field with low residual ripple can be generated.

[0009] In an advantageous embodiment, the slots are arranged in a stator lamination stack consisting of stacked individual laminations, with the stacking direction being the axial direction, i.e., the shaft axis direction of the rotor, which is rotatably mounted relative to the stator. This design offers the advantage of simplified machine manufacturing.

[0010] In an advantageous embodiment, the capacitor has a larger capacitance value than that required for minimum loss operation. The capacitance value is so small that at the rated point, i.e., when the rated power is delivered to the shaft, the power loss does not, and in particular never, lead to impermissible heating. An advantage of this is that a higher starting torque can be achieved, whereby the required higher current generates only slightly more heat loss, since the auxiliary winding has a relatively large amount of copper, i.e., winding sections, compared to the main winding.

[0011] In an advantageous embodiment, one or each coil winding of the auxiliary winding overlaps in the circumferential direction with coil windings of the main winding. The advantage here is that three pole pairs can be generated in a simple manner, whereby the auxiliary winding can be subjected to a high current and a high torque can still be generated.

[0012] In an advantageous embodiment, the auxiliary strand has four groups, the groups being regularly spaced apart from one another in the circumferential direction, each group being formed from two coil windings, in particular from two coil windings arranged concentrically to each other. An advantage of this is that it enables simple manufacturing.

[0013] In an advantageous embodiment, the main strand - two first groups, each consisting of three, in particular concentric, coil windings, and - Two second groups, each consisting of two concentric coil windings, with the first and second groups alternating circumferentially. An advantage of this design is its ease of manufacture.

[0014] In an advantageous embodiment, each of the auxiliary windings overlaps circumferentially with windings of a first group of the main winding and with windings of a second group of the main winding. The advantage here is that a uniform rotating field with low residual ripple can be generated.

[0015] The invention will now be explained in more detail with the help of illustrations: In the Fig. Figure 1 shows a circuit diagram for a stator winding of an electric motor according to the invention. This electric machine according to the invention is designed as an asynchronous motor.

[0016] The electric motor can be powered by a single-phase voltage. The stator winding is designed to generate a rotating magnetic field, thus setting a rotor with a squirrel-cage, which is rotatably mounted relative to the stator, into rotation when the stator winding is energized. Instead of a squirrel-cage rotor, a rotor from a synchronous motor, i.e., a rotor with permanent magnets arranged around its circumference, can also be used.

[0017] The stator winding has one of the main strands, whose connections are in Fig. The terminals are labelled U1 and U2. The stator winding also has an auxiliary winding, the terminals of which are labelled Z1 and Z2.

[0018] The main winding is powered directly from the single-phase AC voltage supplying the motor. The auxiliary winding is connected in series with a capacitor, and this series connection is also powered from the single-phase AC voltage supplying the motor. The capacitor causes a phase shift in the voltage supplying the auxiliary winding relative to the voltage supplying the main winding.

[0019] Preferably, the capacity is dimensioned such that it is larger than a capacity value at which a loss minimum occurs at the rated data of the electric motor.

[0020] This allows for a higher starting torque, although a higher current must also flow. However, this higher current only causes minor losses, since the auxiliary winding is larger than the main winding, and therefore less asymmetrical than with a 2:1 split between main and auxiliary windings.

[0021] Because, as from Fig. As can be seen in Figure 1, the main strand requires five slots per pole and the auxiliary strand requires four slots.

[0022] Overall, the stator lamination stack has 36 slots spaced regularly apart in the circumferential direction, which extend axially and into which the coil windings are inserted.

[0023] According to the invention, the main winding occupies not six but only five stator slots, and the auxiliary winding occupies not three but four slots. Thus, the auxiliary winding has a relatively large amount of copper, and a large capacitor can be used, which can handle a correspondingly high current to generate a large starting torque.

[0024] Each coil winding occupies two of the slots. The main strand has coil windings configured as three concentric windings, namely in slots 5, 6, 7 and, with return windings, slots 12, 13, 14. Two further concentric coil windings of the main strand occupy slots 15, 16, 21, 22.

[0025] Furthermore, the main strand also features coil windings designed as three concentric windings, namely in slots 23, 24, 25 and, with return connections, slots 30, 31, 32. Two further concentric coil windings of the main strand occupy slots 33, 34 and, with return connections, slots 3 and 4.

[0026] The auxiliary strand has four concentric coil winding pairs, the first pair having slots 1, 2 and, on the return side, slots 8, 9. The second pair has slots 10, 11 and, on the return side, slots 17, 18. The third pair has slots 19, 20 and, on the return side, slots 26, 27. The fourth pair has slots 28, 29 and, on the return side, slots 35, 36.

[0027] The connections for wiring the winding sections between the slots are shown in the Fig. 1 are characterized as straight lines oriented circumferentially. In other embodiments of the invention, a different configuration of the grooves is also possible.

[0028] In another embodiment according to the invention, instead of the four-pole machine, a two-pole machine with 18 slots is used, wherein each pole is again assigned five coil windings for the main strand and four coil windings for the auxiliary strand. Reference symbol list U1 first connection of the main line U2 first connection of the main line Z1 first connection of the main line Z2 second connection of the main line

Claims

[1] Electric motor, with coil windings inserted in stator slots, the machine is designed with four poles, wherein a first part of the coil windings are assigned to a main strand and the other coil windings to an auxiliary strand, where the number of coil windings of the main strand is in the ratio of five to four to the number of coil windings of the auxiliary strand, characterized by , that the auxiliary strand has four groups, the groups being regularly spaced apart from each other in the circumferential direction, each group being formed from two coil windings arranged concentrically to each other, where the main strand - has two first groups, each consisting of three, in particular concentric, coil windings, and - has two second groups, each consisting of two concentric coil windings, where the first and second groups alternate in the circumferential direction, where the main strand occupies five stator slots per pole and the auxiliary strand occupies four stator slots per pole. [2] Electric motor according to claim 1, characterized by , that the auxiliary winding is connected in series with a capacitor and the series circuit thus formed is supplied by the alternating voltage supplying the main winding, in particular single-phase alternating voltage. [3] Electric motor according to at least one of the preceding claims, characterized by that the grooves are regularly spaced apart from each other in the circumferential direction. [4] Electric motor according to at least one of the preceding claims, characterized by , that the slots are arranged in a stator laminated core consisting of stacked individual laminations, the stacking direction being the axial direction, i.e., the shaft axis direction of the rotor rotatably mounted to the stator [5] Electric motor according to at least one of the preceding claims, characterized by , that the capacitor has a larger capacitance value than that required for minimum loss operation, where the capacity value is so small that at the design point, i.e. when the rated power is delivered to the shaft, the power loss does not, and in particular never, lead to impermissible heating. [6] Electric motor according to at least one of the preceding claims, characterized by , that one or each coil winding of the auxiliary strand overlaps in the circumferential direction with coil windings of the main strand. [7] Electric motor according to at least one of the preceding claims, characterized by , that each of the auxiliary windings overlaps circumferentially with windings of a first group of the main winding and with windings of a second group of the main winding.

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