How to check the tachometer (Hall sensor) in the washing machine

Have you noticed that the laundry is not wrung out well? Then it’s time to find out what a tachogenerator is in a washing machine, how it works and what to do if it is faulty. After all, it is his task to determine and increase the speed of rotation of the engine.

The device is also called the Hall sensor in honor of the inventor.

The principle of operation of the tachometer

The Hall sensor is a small coil. When the motor rotates, a voltage is formed inside the coil under the influence of a magnet, depending on the speed of the electric motor, it changes. By measuring the voltage, the sensor sends a message to the main module.

Where is the tachometer located in the washing machine? Of course, on the motor shaft – this allows it to effectively perform the specified functions.

Diagnosis of a malfunction of the tachometer

How can a simple user understand that a malfunction has occurred with the Hall sensor? External signs:

  1. The machine abruptly changes the speed of rotation of the drum.
  2. Insufficient number of revolutions for high-quality spinning of linen.
  3. When washing, the drum rotates faster than expected.

But before diagnosing a breakdown, you need to know how to check the tachogenerator in a washing machine. To do this, you will have to remove the CMA engine, so first we will exclude more likely problems:

  • Look at the control panel. Find the release key there and check if it has sunk, which caused a similar malfunction.
  • Restart your washer. Unplug it from the mains for 15-20 minutes, then turn it on. If nothing has changed, then you need to check the tachogenerator.

Progress

Let’s start with disassembling the CM:

  1. Disconnect the machine from the network and communications.
  2. Remove all self-tapping screws around the perimeter of the rear panel.
  3. Take it off and set it aside.
  4. Now remove the drive belt.
  5. Pull it towards you while turning the pulley.

Proceed to the dismantling of the electric motor:

  • Mark the wires leading to the motor in order to make a quality connection in the future.
  • Loosen the bolts holding the motor. Loosening the motor back and forth, remove it from the housing.

Now inspect the Hall sensor in the washing machine: as a result of strong vibrations, its fastening may have loosened, or the contacts have come off. In this case, you just need to restore the connections and tighten the mounting bolt.

If everything is in order, you need to check the resistance of the tachogenerator of the washing machine. There are two ways to do this:

  1. Set the tester to resistance measurement mode. Unclip the wire connectors and remove them from the sensor contacts. By attaching the tester probes to the contacts, check the resistance value. During normal operation, the resistance of the tachometer should be in the region of 60-70 ohms.
  2. Now switch the tester to measure voltage. You need to understand whether the device produces current or not. If it works, then the tachogenerator is working. To check, attach the probes to the sensor contacts while turning the motor by hand. If the values ​​change (approximately 0,2 Volts), then the part is working.

Be sure to check the integrity of the wiring, since the tachogenerator itself is rarely damaged. Perhaps the cause of the malfunction is in the control board – in this case, it is better to contact the service center.

Now you know what a tachometer is. For do-it-yourself diagnostics, we advise you to watch a video on the topic:

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