Many devices and mechanisms of the car are driven by electric motors. In order for all systems to work in harmony, it is necessary to keep the engines in working order, carrying out periodic preventive maintenance and inspection. This will allow timely identification and elimination of malfunctions that disrupt the operation of devices. One of the possible malfunctions in the electric motor is an open circuit in the winding.
It is necessary
- - screwdriver;
- - spanners;
- - ohmmeter;
- - calculator.
Instructions
Step 1
Perform a visual inspection of the motor and its windings. In many cases, it is enough to carefully examine the device to find traces of carbon deposits or breakdowns in the winding. If a three-phase motor operates on only two phases, this will be indicated by a darkening at the front of the coils to which voltage is applied.
Step 2
Inspect the wound rotor motor for damage to slip rings and brush holders.
Step 3
Prepare an ohmmeter and check with this device the insulation resistance, as well as the resistance between the phases and the motor frame. Remove the jumpers from the motor terminals before taking measurements. Close the terminal block to the case and measure the resistance between the bolts holding the leads. If the parameters differ from those stated in the technical documentation, the motor winding is faulty.
Step 4
Check motors with standard voltage or lower with an ohmmeter rated for voltages up to 500V. If you are testing a higher voltage, you will need a device with a voltage of up to 1kV.
Step 5
A sign of a faulty winding is the discrepancy between the resistance measurements between the phases and with respect to the device body. If the insulation resistance is less than 1 MΩ, this indicates a malfunction of the electric motor. In this case, replace the winding or the entire motor.
Step 6
You should not use an ordinary ohmmeter to check turn-to-turn circuits, because such a device will show the difference in resistance only when the short circuit in the turns is already visible to the eye. To make these measurements, use special equipment usually available in auto repair shops.
Step 7
To measure the parameters of a winding with a low resistance, pass a current from the battery through the winding. The current should be in the range from 0.5A to 3.0A. The current strength must be the same throughout the measurement. To calculate the winding resistance, use the following formula: R = U / I; where R is the resistance of the winding; U is the voltage in the circuit; I is the current. The difference in the resistance of the winding from that specified in the technical documentation should not exceed three percent with a working motor and a safe winding.
