During the operation of any equipment periodically breakdowns of a different nature occur, which require high-quality repairs. Common today, electric motors are no exception. Such units can fail as a result of interturn circuit. In such a situation, a seemingly serviceable engine may burn out. That is why experts are trying to timely determine the inter-turn type circuit in order to qualitatively eliminate the cause of the malfunction.
Description
A complex interturn circuit can occur due to a violation of the insulating layer of critical elements in multifunctional electrical units. In the classic engine, in addition to the common short circuit to the housing, other problems are often present. Most often, this can be triggered by the failure of the rotor winding or the stator. Specialists were able to establish that the classic interturn circuit occurs as a result of overheating of the motor. When the device is exposed to elevated temperature, it is difficult to avoid the destruction of the varnish applied by the manufacturer, which acts as a reliable coating. Because of this, the turns are exposed and begin to gradually interact with each other, thereby causing a short circuit. Even if this is a point problem, the engine will still not function as before. It is possible to eliminate damage only with the help of high-quality rewinding.
Elementary check
The first step is 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 anchor is neatly laid on the poles of the inductor, and then the device for turning the armature is fixed on the shaft. You can turn on the stand. The master will have to gently 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 wizard can only read the readings of the device.
Important Nuances
Experts have developed a universal device for checking the inter-turn circuit. But the first thing you need to accurately establish the fact that there is no additional load on the motor. The problem may arise due to clogging of the air system or jamming of the mechanical department. In order to accurately determine the inter-turn short circuit, it is necessary to observe the running engine for some time. In such a situation, the master will notice intense circular arcing. An unpleasant smell of burning insulation may be felt. To eliminate the problem, you need to determine it in a timely manner. With a standard visual inspection, the armature windings should not be swollen or blackened. A burning smell may indicate a problem. The master must ensure that there is no short circuit between the collector plates.
Universal unit
Using the multifunctional device for checking the inter-turn short circuit, it is possible to accurately measure the resistance between the winding and the housing. In working condition, the difference in the received data remains insignificant. If the figure obtained exceeds 11 percent, then a quality repair cannot be avoided. The master will have to replace the entire winding, which will have less resistance. Major repairs should be directed to rewinding defective parts. Such manipulations are available only in special conditions. Work can be entrusted exclusively to specialists.
Multimeter help
The versatility of this device allows you to check the inter-turn circuit in order to timely eliminate the existing breakdown. Any repair work must begin with the disassembly of the motor armature. The reasons may arise for the following reasons:
- Worn and broken brushes.
- The closure between the plates.
- No contact at the terminals.
- Bad insulation.
- Temperature too high for manifold plates.
Many years of experience of experts indicate that a broken starter makes a characteristic humming sound, sparks appear, the intensity of rotation of the armature changes, vibrations form during operation.
DIY repair
To check the inter-turn short circuit at the anchor, 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 check must be performed with an ohmmeter. Resistance should be as low as possible, not more than 9 kOhm. If the circuit is inter-turn, then a certain device is useful for checking the starter armature. You can fix this problem if you align all the wires and clean them of excess debris. If all of the recommendations listed above do not work, all that remains is to rewind the anchor. When wiring the collector terminals, it is necessary to dismantle the rotor and carefully clean the surface with a drill. A burned-out battery can only be identified with the battery.
Option for professionals
Experts are used to using a high-quality device for inter-turn closure. Such a unit is intended exclusively for professional repair of electrical equipment. For work, you need a coil with a bracket. A classic multimeter can only detect an open at anchor. For a better diagnosis, it is better to use an analog tester. Between all lamellas, resistance is necessarily measured. In all cases, the indicators should be identical. In some cases, the windings may not burn out, and the collector remains unscathed. You can determine the inter-turn type closure using an instrument with a sturdy bracket from the transformer. The multimeter is set at 180 kOhm. The probe is neatly closed to ground, and the second is alternately applied to each collector lamella. If the anchor is still not ringing to the mass, then it is absolutely serviceable.
Classic stator closure
Even such a product is subject to interturn closure. First of all, the specialist must check the stator winding for resistance. But this is not the most reliable method. Many factors affect the multimeter, which is why it can display erroneous data. The final result largely depends on the rewind of the engine, as well as on the 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 the engine running. But in this case, there must necessarily be working bearings that are well lubricated. If desired, the master can use an oscilloscope, but such an assembly is notable for its high cost. Because of this, not everyone can purchase an aggregate. The engine should not have traces of oil, smudges. Foreign odors are not permitted. With a quality tester, the windings are checked 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 inter-turn short circuit of the electric motor with the help of a unit built at home. For assembly, you need to prepare transistors KT209 and KT315, variable resistors at 47 kOhm and 1 kOhm. The product can be powered using a battery, as well as a high-quality stabilizer. In addition, you need to install a green LED that will signal that the unit is on, and orange - a control one. In series with these elements include a 30 ohm resistor. It is worth noting that the working board has a compact size, due to which it easily fits in a small case.
Causes of malfunctions
Inter-turn motor short circuit is not a rare problem. Such a malfunction occurs in 50% of all cases of breakdowns. The situation may arise due to increased load on the electrical installation. Improper use of the unit often leads to premature failure. The rated load can be determined from the installation certificate. Overloading can be triggered by mechanical damage to the motor itself. Dry or seized bearings often cause a short circuit. The fact of factory marriage is not excluded. If the electric motor is stored in inappropriate conditions, then this is always fraught with the fact that the winding simply becomes damp.
Resistance change
The definition of inter-turn closure can significantly simplify repair work. To qualitatively check the motor for the fact of insulation resistance, experienced electricians actively use a megger with a voltage of 500 V. This device can accurately measure the insulation resistance of the motor windings. If electric motors have a voltage of 12 V or 24 V, then you simply can not do without the help of a tester. The insulation of such windings is not designed for testing under maximum voltage. The manufacturer always indicates the optimum value in the passport to the unit. If testing showed that the insulation resistance is much less than the optimal 20 MĪ©, then the windings must be disconnected and carefully checked each separately. For the assembled motor, the indicator should not be lower than the 21 Mom. If the product has been lying in a damp place for a long time, then before use it must be dried for several hours with a glow lamp.
Transformer malfunctions
Experienced specialists are used to using a universal indicator of inter-turn closure, which greatly simplifies the search for breakdowns. But even professionals should remember that the choice of the most suitable power source 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 circuit of the turns between themselves.
This problem can not always be determined using a classic multimeter. The unit must be carefully inspected for visual defects. The winding wire has a varnish insulation. In the event of a breakdown between the turns, resistance occurs that is higher than 0. In this situation, equipment overheating may occur. During visual inspection, the transformer should not have traces of soot, charred particles, bloated factory fill, blackening. The master can find out the rated voltage from the documentation supplied with the unit. If the difference in performance 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 crucial element to specialists who have all the necessary skills.