Noticed that the laundry is badly wrung out? 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 enhance the engine speed.
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 generated inside the coil under the influence of a magnet, and it changes depending on the speed of the electric motor. By measuring the voltage, the sensor sends a message to the main module.
Where is the tachometer in the washing machine? Of course, on the shaft of the electric motor - this allows it to effectively perform the specified functions.
Diagnostics of malfunction tacho
How can a simple user understand that a malfunction has occurred with the Hall sensor? External signs:
- The machine dramatically changes the speed of rotation of the drum.
- Insufficient number of revolutions for a high-quality spin of linen.
- When washing, the drum spins faster than it should.
But before you diagnose a breakdown, you need to know how to check the tachogenerator in the washing machine. To do this, you will have to remove the CMA engine, so first we eliminate the more likely problems:
- Look at the control panel. Find the spin key there and check if it has sunk, which caused a similar malfunction.
- Reboot the washer. Disconnect it from the network for 15-20 minutes, then turn it on. If nothing has changed, then a tachogenerator check is needed.
Working process
Let's start with disassembling the CM:
- Disconnect the machine from the network and communications.
- Unscrew all the screws along the perimeter of the rear panel.
- Remove it and set it aside.
- Now remove the drive belt.
- Pull it toward you while scrolling the pulley.
Proceed to dismantle the electric motor:
- Mark the wires leading to the motor in order to make a quality connection in the future.
- Remove the bolts holding the engine. Shaking 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 could weaken, or the contacts were removed. In this case, it is enough for you to reconnect and tighten the fastening 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:
- Set the tester to resistance measurement mode. Unclench the connectors of the wires and remove them from the sensor contacts. Having put the tester probes to the contacts, check the resistance value. With normal operation, the resistance of the tachometer should be in the region of 60-70 Ohms.
- Now switch the tester to measure voltage. You need to understand: the device produces current or not. If it produces, then the tachogenerator is working.
To test, attach the test leads to the sensor contacts while simultaneously rotating 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 self-diagnosis, we recommend that you watch the video on the topic: