You will need
- - screwdriver;
- - wrenches;
- - ohmmeter;
Perform a visual inspection of the motor and its windings. In many cases, quite carefully inspect the device to detect traces of soot or place of breakdown of winding. If a three phase motor running on just two phases, this will be indicated by the darkening in front of the coils to which voltage is applied.
A motor with a wound rotor inspect for damage kontaktnyh rings and brush holders.
Prepare an ohmmeter and check with the help of this device the insulation resistance and the resistance between the phases and the casing of the engine. Before taking measurements, remove the jumpers from the motor terminals. Snap the terminal block onto the housing and measure the resistance value between the bolts that secure conclusions. If parameters other than stated in the technical documentation, the motor winding is faulty.
Motors with a standard voltage or lower, use an ohmmeter to measure, designed for voltages up to 500V. If you check a higher voltage you will need a device with voltage up to 1kV.
A sign of a faulty coil is the discrepancy between the results of measurements of resistance between the phases and relative to the housing of the device. If the insulation resistance is less than 1 Mω, this indicates a malfunction of the motor. In this case, replace the coil or entire engine.
You should not use an ordinary ohmmeter to check for interturn short circuits, because such a device will show the difference in the resistance only when a short circuit in the coils and so apparently on the eyes. To conduct these measurements use special equipment commonly available in auto repair shops.
For measuring windinghaving low resistance, flow through the coil current from the battery. Current should be in the range from 0.5 A to 3.0 A. the amperage should be the same throughout the measurements. To calculate the resistance of the winding using the following formula:R = U / I; гдеR – resistance winding;U – voltage;I – current.The difference of the resistance of the windings from that specified in the technical documentation should not correct the engine and secure the coil to exceed three percent.