How to test a washing machine capacitor with a tester

It is quite easy to understand that something is wrong with the starting capacitor of the electric motor. The malfunction can be determined visually - the body of the part is deformed, bulging at the top. In some cases, the device looks normal externally, so you will have to ring it with a multimeter. Let's figure out how to do this.

Testing a polar type element

How to check the capacitor of a washing machine with a multimeter? The work can be done at home, with your own hands. Diagnostics of starting devices should be performed by removing them from the electrical circuit. Due to this, you can get more accurate readings.

An automatic washing machine can be equipped with a polar or non-polar capacitor. When checking the first type of device, it is necessary to observe one important condition - its capacity must be more than 0.25 μF. Let's figure out how to ring such a part with a tester.

The technology for diagnosing a polar capacitor with a multimeter will be as follows:

short-circuit the capacitor with tweezers, a fork, pliers, a screwdriver or other metal object. This is necessary to discharge the device. If everything is done correctly, a spark will appear;

• Switch the tester to ohmmeter mode,
• Place the multimeter probes against the capacitor contacts, remembering to take into account the polarity,
• Evaluate the readings on the device display.

If the tester beeps and the display shows "0", then there is a short circuit. This is what caused the capacitor to break. The unit displayed on the multimeter immediately after connecting the probes will indicate an internal break. In both cases, the starting device will have to be replaced.

It is very important to perform diagnostics correctly, otherwise the device readings may be incorrect. For example, it is forbidden to touch the probes during measurements. The human body has low resistance, so the current will "flow" past the capacitor and the multimeter will show completely different values.

Discharging the capacitor is a necessary step before diagnosing it. Especially if the device is high-voltage. This is done, firstly, for safety reasons, and secondly, so as not to damage the multimeter. The tester can burn out if the residual voltage of the element is high.

Testing a non-polar element

It is even easier to test non-polar starting devices with a tester. First, the unit of measurement is set on the multimeter - megaohms. Then the probes are connected to the capacitor contacts. If the device display shows a value of less than 2 mOhm, then the element is faulty.

If you need to check a non-polar capacitor with a voltage of over 400 volts, you can do this by recharging it from a device protected from short circuits. A resistor with a resistance of at least 100 ohms is connected in series with the element. Such precautions will prevent a sharp "jump" of current during startup.

There is also another method of examining a single-pole starting device - checking for a spark. The part must be charged to the working capacity. Then the contacts should be short-circuited with a suitable device with an insulated handle (pliers or a screwdriver). A strong discharge will indicate the operability of the element. After the spark appears, the resistance on the capacitor legs is measured with a tester.

Checking the capacity

One of the key characteristics of a capacitor is its nominal capacity. Over time, the indicator may decrease, and, consequently, the device will accumulate less and store the charge worse. To check the performance of the starting element, the capacity is measured and compared with the value marked on the case. The procedure has some specific features.

Thus, with the help of a standard, inexpensive multimeter it will not be possible to quantitatively measure the capacity of a capacitor. It will only be possible to make sure that the device works. To check the element, the tester is switched to the dialing mode.

After touching the capacitor legs with the probes, a characteristic sound should be heard. Then the multimeter wires should be swapped, and the squeak should be repeated. It will be heard if the starting device capacity is more than 0.1 μF.

To obtain accurate results, you will have to find a more professional multimeter, which has special contact connectors and the ability to adjust the plug to calculate the capacity of the device. Before starting diagnostics, such a tester must be set to the nominal value indicated on the body of the starting capacitor.

Next, the capacitor is discharged with metal. After that, its legs are inserted into special "sockets" provided on the multimeter. The tester screen should display a capacity that matches the nominal one, a small deviation is allowed. If the indicator differs significantly from the norm, then the starting device is damaged.

Is the voltage correct?

Another way to make sure that the capacitor is working is to measure its voltage and compare the obtained value with the nominal one. During the work, a power source will be needed, and its voltage must be lower than that of the starting device being tested.

Let's say if the capacitor is 25 volts, then a 9 volt power source will be enough. Next, you need to switch the tester to ohmmeter mode, connect its probes to the element's legs, observing the polarity, and wait about 5 seconds.

The tester screen should display the capacitor voltage. When the value corresponds to the standard, the starting device is working properly. Otherwise, the element will have to be replaced.

Advice from experts

When checking capacitors, craftsmen face a certain difficulty. During soldering, under the influence of heat, even an initially serviceable element can be damaged. However, for high-quality diagnostics, the starting device should be removed from the circuit so that it is not shunted by sensors located nearby. Therefore, some nuances should be taken into account.

When the tested starting device is soldered into the circuit, the repaired washing machine should be started. If the machine's functionality has been restored, it is better to remove the old capacitor again and replace it with a new one.

Another recommendation is to reduce the time of testing and reduce the likelihood of damage to the capacitor by desoldering not two legs, but only one. However, this option is not acceptable for all electrolytic elements. Therefore, first consider whether this method is possible in your case.

If the circuit is quite complex, with a large number of capacitors, then in order to find a faulty element, it is better to check the voltage readings of each one without removing the part. A starting device whose parameters do not correspond to the nominal value must be unsoldered and replaced with a new one.

Having discovered that the circuit is "failing", it is necessary to check the production date of each starting device. Capacitors tend to "dry out" over time, so even if the element is in good condition, but was manufactured 5-7 years ago, it must be replaced with a new one. On average, over 5 years, the drying out of the part is approximately 65%, which is why the operation of the circuit is disrupted.

It is worth understanding that modern new generation multimeters are only capable of testing capacitors with a power of up to 200 μF. If the value is higher, the tester will fail. Even the provided fuse will not save the device.