How to diagnose the condenser with a multimeter: general recommendations and principles of measurements
Capacitors are found in a variety of equipment. But they often lead to malfunctions of the mechanisms. In order to timely determine the malfunction and eliminate it, it is necessary to understand the general principles of checking the capacitor by a multimeter. This method is the simplest.
Consider the options for applying an inexpensive and effective device to identify elements that failed. The article presents in detail various types of capacitors, as well as the sequence of their verification. Thanks to practical advice, you can easily detect a malfunction in any scheme.
The capacitors are a device consisting of two plates with the property of electrical conductivity.
The plates do not contact each other. Between them there is a space that can be filled with oxygen or any dielectric substance.
How to test electric fan capacitor using analog multimeter
The main value is the capacity, it is measured in pharads. The value is calculated with the capacitor ability to accumulate the amount of energy equal to 1 pendant, with an indicator of voltage difference 1 volts between 2 plates. Value 1 pendant is very large. The containers of modern devices vary from milliparad to picoparad.
The capacity of these elements decreases or increases due to the size of the plates and the dielectric distance between them. With an increase in the height and width of the plates, reduce the width of the dielectric, which helps to increase the capacity.
The capacitor works as the following principle:
- Alternating voltage charges the conductive plates of the device.
- On these plates there is a change in potentials.
- With a decrease in voltage in the circuit, the capacitor gives part of the missing energy, stimulating the alignment of the voltage.
When working under load of constant voltage, there is no potential change on the plates. Current is issued by pulsed discharges, according to the established polarity. The following will be given a detailed description of the varieties of capacitors and the spheres of their use.
No tank measurement
It is possible to call the polar or non.Polar capacitor with a multimeter that does not have a special function in the maximum resistance mode at which it is charged with direct current.
This testing method is suitable even for elements such as SMD capacitor (for surface installation) or film capacitor. Checking the polar element is only necessary to observe polarity.
- Discharge the element by shorting its legs;
- Set the maximum limit of resistance measurement. Up to Mega, if the device allows;
- Connecting the black probe of the multimeter to the COM nest is zero or, in our case, minus, and the red probe is in the nest for measuring voltage and resistance;
- Touch the minus of the part with a black probe, and red. Plus;
- Monitor the readings of the device.
What to happen in this case? The multimeter begins to charge the part with direct current. During charging, its resistance increases.
The rapid growth of resistance indications up to the value of “1” (infinitely large) means that the capacitor is potentially working, although in this way it is impossible to determine its actual capacity.
Possible error! During such a check, you cannot touch the probes or legs of the element with your fingers. You make it with the resistance of your own body, and the tester will show your own resistance. It is recommended to use crocodile probes, if any.
The main malfunctions of the capacitors
Several malfunctions are distinguished, which are characteristic of the capacitors:
- Leakage above the set norm. Occurs due to changes in the resistance of the dielectric material. With this breakdown, the container is reduced, and the device is not able to maintain the charge for a long time.
- Cliff. The essence of the damage is an electrical rupture of conductors that no longer have an electrical connection. The reason may be a blow, strong shaking or oscillations. The condenser marriage or violation of the rules for its application cannot be ruled out.
- Breakdown. Occurs in case of exceeding the operating voltage above the permissible norm. With this breakdown, further use of the container is impossible due to the appearance of a short circuit in the scheme.
You can include others in the list of malfunctions. A decrease in capacity, high equivalent sequential resistance, and t. D.
The most risk zone contains aluminum electrolytic capacitors, which are often installed as a filter for pulsating stresses in different rectifier devices.
Checking capacitors without falling out
Capacitors can not fall out of the board for verification. The only condition is that the fee should be de.Energized. After de.Energization, you need to wait a bit while the capacitors are discharged.
It should be understood that getting a 100% result without losing the element from the board will not work. Details nearby interfere with a full.Fledged check. Can only be made in the absence of breakdown.
In order to check the capacitor for serviceability, without falling it out, with the conclusions of the capacitor are simply touched by probes to measure the resistance. Based on the type of capacitor, the measurement of this parameter will also differ.
The main types of capacitors
Literally a few minutes of attention should be paid to the principles of the structure and operation of the capacitors, as well as the varieties of these elements of the scheme. So it will be easier to understand what the methodology for checking their performance is built on.
So, the capacitor is a very common element of the electric circuit in which the charge is accumulated. The device is simple. Unlike many other elements, there are no semiconductor transitions here. In fact, these are only two significant.Carrying plates (they are usually called linings) of equal sizes, spaced at a short distance from one another, that is, there is no direct electrical contact between them and should not be there. This lumen is filled with dielectric material.
The accepted convention of the capacitor in the schemes just clearly shows the principle of its device.
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Domestic.Conducting plates shared by thin clearance tend to accumulate an electric charge.
It is clear that there is no conduction through the capacitor in a direct current circuit, since the circuit, in fact, is broken. But on its linings, an electric charge accumulates (condenses). And the larger the area of these pads, the greater the charge can be accumulated. The indicator of these capabilities is the capacity of the capacitor.
This physical quantity is measured in farades (f). One Farad is the ability to accumulate 1 pendant pendant with a potential difference on linings of 1 volt. But let these “one.Time” do not mislead: in fact, 1 F is just a huge indicator. In fact, you have to deal with much smaller quantities:
Despite the community of the principle of device and action, in their design, capacitors can still have significant differences.
The variety of capacitors both in operational parameters and in size. Very wide
First of all, they can be divided into two large groups. Polar and non.Polar capacitors.
- For non.Polar elements, the mutual arrangement of their pads in the general scheme does not matter. Such capacitors are available in the following basic “forms”.
Ceramic capacitors. As a dividing dielectric layer between linings, a ceramic composition is used. These elements are characterized by compactness, a wide range of permissible working stresses, cheapness along with a rather high reliability and durability.
To achieve higher capacity indicators, it is necessary to increase the area of the pads. This is achieved by coagulation into a roll (or into the “accordion”) of two conductive ribbons with a special metallized coating (or even aluminum foil ribbons) with a dielectric gasket placed between them. By this principle, paper, metal, mica, mica and the silver-luxury capacitors are arranged for them.
The non.Polar include powerful launch capacitors available in many models of household appliances equipped with electric drives. They are assembled in a fairly overall cylindrical or cubic.Shaped body, have linings made of metallized polypropylene film and are filled with dielectric oil.
The principle of the start of the start.Up capacitor: 1. Metal case; 2. Linings. Stripes of polypropylene film with vacuum metallized spraying; 3. Dielectric film laying; 4. Filling from dielectric non.Toxic oil; 5-Connection Connections for connecting to the electrical circuit of the device.
It is not for nothing that they are called launching. They are able to accumulate a very significant charge for the production of a powerful launch pulse and to increase the power factor of electrical installations. They are capable of smoothing significant fluctuations in high voltage systems.
The most common polar capacitors in the aluminum cylindrical case are today. Often such elements also call “electrolytic”. This name is predetermined by the fact that the free space between the linings is filled with a special electrolyte. The range of dimensions and electrical indicators is very wide, but if non.Polar compact capacitors are most often limited to microfarad units by the capacity, then the electrolytic account can even go to thousands of μF, that is, units of MF. Three orders of magnitude more!
Electrolytic polar capacitors
A step forward was the appearance of tantalum polar capacitors, in which the ratio of size and possible indicators of the container is much higher. That is, this is the best option for cases where the compactness of the scheme is required along with the high capacity. True, such details are much more expensive, and in addition. Too sensitive to pulsation of currents and to excesses permissible stresses, which often disables them.
Tantalum polar capacitors. Miniature “droplets” with very impressive capacity indicators.
Not all forms of the release of capacitors were considered here, but the principle of their structure, regardless of appearance, remains the same.
Repair of household appliances
The failure of the capacitors leads to the fact that household appliances cease to function. The testing technique described above will determine the faulty detail. After its discovery, it is enough to replace the faulty element to restore the operability of the TV, microwave of the stove or vacuum cleaner.
Knowing how to check the capacitor by the multimeter, you can check how efficient the starting element in the car generator is or determine the trambler malfunction.
Attention! Before you start repairing any electrical devices, you must make sure that they are disconnected from the power supply. Manipulations with devices under voltage can cause electric shock damage.
Short circuit check
Determination of KZ in the call mode
How to call capacitors by a multimeter? You need to turn on the multimeter in the call mode or measurement measurement and attach the probes to the condenser outputs. Depending on the capacity, the multimeter will either immediately show endless resistance, or after some time (from a few seconds to tens of seconds). If the device constantly squeaks in the call mode (or shows a very low resistance in the resistance measurement mode), then the capacitor can be safely thrown away.
Determination of the capacitor short circuit using the LED and battery
If there is no multimeter (and even the old Soviet “chain” is not), then you can try to connect the LED or light bulb to the battery through the studied capacitor. T.To. A proper capacitor has sooo high resistance to permanent current, the light should not burn.
Although, if the capacitance of the capacitor is quite large, the light can flash for a short time (until the capacitor is charged). If the LED burns constantly, the capacitor is 100% faulty. If when checking the capacitor, the effect of gradual growth in resistance is observed up to infinity (well, or the LED flashes and goes out for a while), then the capacitor has absolutely certain capacitance.
Therefore, a check for a cliff can not be done.
Checking the capacitor with a 220V light bulb
Suitable for high.Voltage non.Polar capacitors (for example, launch capacitors from washing machines, pumps, various machines, etc.P.). All you need to do is just connect a low-power incandescent lamp (25-40 watts) through the capacitor.
Replacement and selection of launch/working capacitor
If there is an original capacitor, it is clear that it is simply necessary to put it in place of the old and everything. Polarity does not matter, that is, the condenser conclusions do not have the designations plus “” “and minus”-“and they can be connected as you like.
Electrolytic capacitors cannot be used categorically (you can recognize them by smaller sizes, with the same capacity, and the designation plus and minus on the case). As a result of application. Thermal destruction. For these purposes, manufacturers specifically produce non.Polar capacitors for working in an alternating current circuit, which have convenient fastening and flat terminals for quick installation.
If there is no desired face value, then it can be obtained by a parallel connection of capacitors. The total capacity will be equal to the sum of two capacitors:
That is, if you combine two capacitors of 35 μF, we get a total capacity of 70 μF, the voltage in which they can work will correspond to their rated voltage.
This replacement is absolutely equivalent to one capacitor of a larger capacity.
If the wires are mixed up during the replacement, then the correct connection can be viewed according to the scheme on the case or here: the condenser connection scheme to the compressor
Types of capacitors
To start powerful compressors engines, oil.Filled non.Polar capacitors are used.
The case inside is filled with oil for good heat transfer to the surface of the case. The case is usually metallic, aluminum.
The most affordable capacitors of this type CBB65.
To launch a less powerful load, such as fan engines, use dry capacitors, the body of which, usually plastic.
The most common capacitors of this type CBB60, CBB61.
Terminals for the convenience of connecting double or calculated.
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The company’s managers will answer all your questions, select the necessary equipment and prepare a commercial offer.