Basic knowledge of motor windings, multi-winding multi-speed motor winding data selection
Multi-winding multi-speed motor winding data selection
The winding of a multi-speed motor generally has only one set of windings. By changing the way of winding wiring, the number of poles of the motor winding is changed to achieve the purpose of speed regulation. It is relatively rare to use a set of windings to achieve a speed-changing motor. This article provides data for two motor windings.
First, the first
Nameplate:
Core size:
Outer diameter 240mm, inner diameter 145mm, length 277mm, number of slots 36
Winding data:
Second, the second
Nameplate:
Core size:
OD 187mm, inner diameter 123mm, length 165mm, number of slots 36
Winding data:
Basic knowledge of motor windings
1. Mechanical angle and electrical angle
It is known from mechanics that the circle can be equally divided into 360°, which is the mechanical angle usually mentioned. In the field of electromagnetism, the angle unit of the electromagnetic relationship is called the electrical angle. It divides the sinusoidal alternating current into 360° on the abscissa, that is, the conductor space changes correspondingly when passing through a pair of magnetic poles. ° Electrical angle.
Therefore, the relationship between the electrical angle and the mechanical angle in the motor is:
Electrical angle α = pole logarithm xPx360°
For example, for a two-pole motor, the pole pair p=1, then the electrical angle is equal to the mechanical angle. For a four-pole motor, p=2, then the motor has two pairs of poles on one circumference, and the corresponding electrical angle is 2×360°. =720°. And so on.
2, the pole distance (τ)
The pole pitch of the winding refers to the distance of each pole from the circumferential surface of the core. Usually there are two ways to express the pole distance, one is expressed by the length; the other is expressed by the number of slots, which is customarily expressed in the number of slots.
τ=Z1/2p
3, pitch (y)
The number of slots occupied by the two component sides of each coil of the motor winding is called the pitch, also called the span.
When the coil element pitch is equal to the pole pitch pair, it is called the full-distance winding, y=τ
When the pitch of the coil element is less than the pole pitch, it is called short-distance winding, y<τ
When the pitch of the coil component is greater than the pole pitch, the long-distance winding y>τ is called
Because short-distance windings have many advantages such as short-end electromagnetic wire materials and high power factor, short-circuit windings are used in the double-stack windings with more applications.
4, winding coefficient
The winding coefficient refers to the product of the short-distance coefficient and the distribution coefficient of the AC distributed winding, that is,
Kdp1=Kd1Kp1
5, slot angle (α)
The electrical angle between two adjacent slots of the motor core is called the slot angle, which is usually denoted by a, ie
α=total electrical angle/z1=p×360°/z1
6, phase belt
The phase band refers to the area occupied by each phase of the winding of each phase, usually expressed by the electrical angle or the number of slots. If the winding of the three-phase motor under each pair of poles is divided into six regions, then three at each pole. Since the groove angle α=360°P/Z, if the motor is 4 poles and 24 slots, the width of each phase per area is
Qα=Z/6P*360P/Z=60°
The windings wound in this way are called 60° phase-band windings. Because of the obvious advantages of 60° continuous phase windings, most of them are used in three-phase motors.
7, the number of slots per phase per phase (q)
The number of slots per phase per pole refers to the number of slots occupied by each phase of the winding of each phase. The number of coils to be wound in each phase of each phase winding is determined according to it. which is
q=Z/2Pm
Z: number of core slots; 2P: number of motor poles; m motor phase number.
The result of the calculation, if q is an integer, is called an integer slot winding; if q is a fraction, it is called a fractional slot winding.
8, the number of conductors per slot
The number of conductors per slot of the motor winding shall be an integer, and the number of conductors per slot of the double winding shall also be an even integer. The number of conductors per slot of a wound rotor winding is determined by its open circuit voltage, and the number of conductors per slot of a medium-sized motor wound rotor must be equal to two. The number of conductors per slot of the stator winding can be calculated by:
NS1=NΦ1m1a1/Z1
NS1: number of conductors per slot of the stator winding;
NΦ1: the number of conductors per slot calculated by air gap magnetic density;
M1: the number of stator winding phases;
A1: the number of parallel branches of the stator windings;
Z1: Number of stator slots.
9, the number of series conductors per phase
The number of series conductors per phase refers to the number of bus turns in series for each phase winding in the motor. However, the number of serial bus turns is related to the number of parallel branches in each phase winding. If the number of parallel branches of the motor is one way, then the number of turns of all series lines of the coils of the motor should be added to form a phase. The number of bus turns in the winding.
For example, the number of parallel branches in each phase winding of the motor, that is, the motor is 2-way connection, 3-way connection, etc., at this time, the number of series-connected conductors in each phase can only be one of the number of turns connected in series with one of the windings. quasi. Since the number of series line turns in each branch in the phase winding is the same, it is impossible to increase the series line 并联 after being connected in parallel to form a phase winding.
10, the total number of coils
The windings in the motor are composed of coils of various sizes and shapes. Since each coil has two components embedded in the core slot, that is, each coil is embedded in two slots. In a single-layer winding, since only one coil element side is embedded in each slot, the total number of coils is only equal to half of the total number of slots; in the double-layer winding, two coil elements are embedded in the upper and lower layers in each slot, so its The total number of coils is equal to the number of core slots.
If you want to buy a household appliance motor, please pay attention to synchronous motors.
