During the operation of any equipment, breakdowns of a different nature periodically occur, which require high-quality repairs. Electric motors common today are no exception. Such units can fail as a result of an interturn circuit. In such a situation, a serviceable, at first glance, engine may burn out. That is why experts are trying to timely determine the interturn type closure in order to qualitatively eliminate the cause of the malfunction.
Description
Complicated turn-to-turn short circuit may occur due to a violation of the insulating layer of critical elements in multifunctional electrical units. In a classic engine, in addition to the common ground fault, there are often other problems. Most often, this can be triggered by the failure of the rotor or stator winding. Experts were able to establish that the classicalinterturn short circuit occurs as a result of overheating of the motor. When the device is exposed to an elevated temperature, it is difficult to avoid the destruction of the varnish applied by the manufacturer, which acts as a reliable shell. Because of this, the turns are exposed and begin to gradually interact with each other, thereby causing a short circuit. Even if it's a point problem, the engine still won't function as it used to. It is possible to eliminate the breakdown only with the help of high-quality rewind.
Elementary check
First of all, you need to carefully install the inductor on the platform of the brake product and plug it into the network. The switch should be moved to position 4. The armature is carefully placed on the poles of the inductor, after which a device for turning the armature is fixed on the shaft. You can turn on the stand. The master will have to carefully press the probes of the contact assembly to two adjacent armature collectors. Turning the mechanism a little, you need to find the position at which the readings of the mechanism will be at the maximum mark. Using a resistor, set the arrow of the device to the most convenient scale mark. It is necessary to gradually rotate the anchor, without changing the spatial position of the probes. The master can only read the readings of the device.
Important nuances
Experts have developed a universal device for checking the interturn circuit. But first of all, it is necessary to establish precisely the fact that there is no additionalmotor load. The problem may occur due to clogging of the air system or jamming of the mechanical department. In order to accurately determine the inter-turn circuit, it is necessary to observe the running engine for some time. In such a situation, the master will notice an intense circular spark. There may be an unpleasant smell of burnt insulation. To eliminate the problem, you need to identify it in a timely manner. By standard visual inspection, the armature windings should not be swollen or blackened. Burning smell may indicate a problem. The technician must ensure that there is no short circuit between the collector plates.
Universal unit
With the multi-functional turn-to-turn short circuit tester, you can accurately measure the resistance between the winding and the case. In working condition, the difference in the received data remains negligible. If the obtained indicator exceeds the mark of 11 percent, then high-quality repairs cannot be avoided. The master will have to replace the entire winding, which will have less resistance. The main repair work should be aimed at rewinding faulty parts. Such manipulations are available only under special conditions. The work can be entrusted exclusively to specialists.
Help multimeter
The versatility of this device allows you to check the interturn circuit in order to timely eliminate the existing breakdown. Any repair work should begin with the disassembly of the motor armature. Reasons may arise fromthe following reasons:
- Wear and breakage of brushes.
- Short circuit between plates.
- No contact on the terminals.
- Bad insulation.
- Temperature too high for manifold plates.
Many years of experience of experts shows that a broken starter makes a characteristic hum sound, sparks appear, the intensity of rotation of the armature changes, vibrations are generated during operation.
Self Repair
To check the turn-to-turn short circuit at the armature, you need to carefully attach the lamp starter to the collector plate. You need to see if the light comes on or not. If the bulb worked, then the master needs to think about replacing the winding or the entire rotor. But if there is no reaction, the test must be performed with an ohmmeter. The resistance should be as low as possible, no more than 9 kOhm. If the circuit is interturn, then a certain device will come in handy to check the starter armature. You can fix this problem if you align all the wires and clean them of excess debris. If all of the above recommendations did not work, it remains only to rewind the anchor. When unsoldering the collector leads, it is necessary to dismantle the rotor and carefully clean the surface with a drill. A burnt battery can only be identified using a battery.
Pro Option
Specialists are accustomed to using a high-quality device for inter-turn circuits. This unit is intended exclusively for professional repair.electrical equipment. To work, you need a coil with a bracket. With a classic multimeter, you can only determine a break at anchor. For better diagnostics, it is better to use an analog tester. Between all the lamellas, the resistance must be measured. In all cases, the indicators must be identical. In some cases, the windings may not burn out, and the collector remains intact. You can determine the interturn type closure using a device with a strong bracket from the transformer. The multimeter is set to 180 kOhm. The probe is carefully closed to ground, and the second one is alternately applied to each collector lamella. If the anchor still does not ring to ground, then it is absolutely working.
Classic stator short circuit
Even such a product is subject to interturn short circuit. First of all, the specialist must check the stator winding for the fact of resistance. But this is not the most reliable method. Many factors affect the multimeter, which may cause it to display erroneous data. The final result largely depends on the rewinding of the engine, as well as on the old age of the iron itself. Conventional clamps can measure current and resistance. If the master has the necessary experience, then he can determine the breakdown even by the sound of a running engine. But in this case, there must be working bearings that are well lubricated. If desired, the master can use an oscilloscope, but such a unit is very expensive. Because of this, not everyone can purchase the unit. There must be no marks on the engineoils, leaks. Foreign odors are not allowed. A quality tester checks the windings for resistance. If the results differ from each other by more than 11%, then the cause of the breakdown may lie in the circuit.
Homemade fixture
You can eliminate the interturn short circuit of the electric motor using a unit built at home. For assembly, you need to prepare transistors KT209 and KT315, variable resistors of 47 kOhm and 1 kOhm. The product can be powered by a battery, as well as a high-quality stabilizer. Additionally, you need to install a green LED, which will signal the inclusion of the unit, and orange - control. A 30 ohm resistor is connected in series with these elements. It is worth noting that the working board has a compact size, due to which it can easily fit into a small case.
Causes of malfunctions
Turn-to-turn shorting of an electric motor is not a rare problem. Such a malfunction occurs in 50% of all breakdowns. The situation may arise due to the increased load on the electrical installation. Improper operation of the unit often leads to premature failure. The rated load can be determined from the installation passport. Overloading can be triggered by mechanical damage to the motor itself. Dry or seized bearings often cause a short circuit. The fact of a factory marriage is not excluded. If the motor is stored in improper conditions, then this is always fraught with the fact that the windingjust damp.
Change in resistance
Determining the interturn short circuit allows you to significantly simplify the repair work. In order to qualitatively check the motor for the fact of insulation resistance, experienced electricians actively use a megger with a voltage of 500 V. Such a device can accurately measure the insulation resistance of the motor windings. If the electric motors have a voltage of 12 V or 24 V, then you simply cannot do without the help of a tester. The insulation of such windings is not designed for testing at maximum voltage. The manufacturer always indicates the optimal value in the passport for the unit. If testing has shown that the insulation resistance is much less than the optimal 20 MΩ, then the windings must be disconnected and carefully checked each separately. For the assembled motor, the indicator should not be lower than the prescribed 21 Mohm. If the product has lain in a damp place for a long time, then before use it must be dried for several hours with an incandescent lamp.
Transformer malfunctions
Experienced specialists are accustomed to using a universal interturn short circuit indicator, which greatly simplifies the search for breakdowns. But even professionals should remember that the choice of the most suitable power supply and its location directly depends on the number of powered products and the type of connection. The transformer has a fairly common malfunction - an unexpected short circuit between the turns.
This problem cannot always be determined with a classic multimeter. The unit must be carefully inspected for visual defects. The winding wire has varnish insulation. In the event of a breakdown between the turns, resistance arises that is higher than 0. In such a situation, overheating of the equipment may occur. During visual inspection, the transformer should not have traces of soot, charred particles, swelling of the factory fill, blackening. The master can find out the rated voltage from the documentation attached to the unit. If the difference in indicators is 45% or more, then the winding is out of order. In order not to aggravate the situation, it is better to entrust the repair of such a critical element to specialists who have all the necessary skills.
