When using electric motors, reversing the engine is considered an integral function that is required for 85% of the applied electrical circuits. Reverse motor - is change of the rotor in the reverse direction. Change the direction of movement is possible in any motor as direct current and asynchronous operating with AC.
Why do you need a reverse engine?
Many of the mechanical action in household and industrial applications, are carried out using an asynchronous engine. In connection with what is often a need to change the direction of motion, starting from the tasks performed. Sometimes the reverse function for the mechanism is constant, and sometimes - time.
- The first varieties are all hoisting machines, cranes, electric shut-off and control devices and actuators operating in the "open / close".
- The other reverse species include arrangements in which this feature is used very rarely, usually in emergency situations: conveyors, escalators, pumping units.
reversing function of the motor is sometimes used for braking, since when disconnecting it from the mains, a rotor, having considerable inertia, continues its work. This causes a momentary reverse start engine braking operation. This method is called by the opposition.
The principle of reverse movement
To change the direction of rotation of an AC motor, you must change the magnetic field, causing the movement in the opposite direction. Since the magnetic fields each wire connected to the positive and negative current replacement main and trigger wires will cause the motor to rotate in the reverse direction. This simple method of switching wires acts as the polarity of the magnetic field is reversed.
How to implement a reverse chart?
To change the rotation direction of the rotor, it is necessary to swap two of the three phases of the motor winding. Then the electromagnetic field of the stator changes its direction of movement, the rotor in the initial period of time, moving by inertia, will be slowed down, until finally stops. And only then it will spin in the other direction.
Replacement polarity electric start winding can be done with the control tumbler scheme. It can pick up with 2 or 3 fixed positions and 6 outputs. Choosing such a device is necessary for current load and the permitted voltage.
Skip current to toggle preferably the auxiliary winding, which runs short. Listed, will provide an opportunity to significantly increase the service life of the contact group.
Reversing asynchronous motor capacitor starting to perform better in the following way:
- In severe start-up in parallel to the main capacitor using the average momentary contact with the PNV, the additional capacitor is connected.
- In such an example, the reverse switch toggle locked rotor only, and not when it rotates.
- Random changes of direction of the motor work under stress, is associated with huge current surges that depletes his Moto resource. For this reason, the seat reverse toggle on the equipment must be chosen in such a way as to make it impossible to accidentally switching it while running. It is better to set it in some depth construction site.
If the motor does not work properly after the assembly circuits require twice to double-check that the wires go to the correct terminals of the switch. And also make sure that the wiring is not loose or damaged.
It is recommended to use a magnifying glass to make sure that the connections are correct, and even the thinnest thread wires accidentally touches another wiring or terminals.