During the use of PILZ safety relays, various faults often occur due to various reasons, such as low product quality, improper use, and poor maintenance. For the electronic PILZ safety relay, because there are few types used on the locomotive, its faults and handling, as well as inspection and testing have their own characteristics. Here, the faults and handling of the contact PILZ safety relay are mainly introduced.
The most common ones are the following:
(1) Contact failure
1. The phenomenon of unbreakable due to the mechanical engagement of the contacts (the needle-like projections formed on the contacts and the pits bite each other), fusion welding or cold welding.
2. The phenomenon that the circuit cannot be normally turned on due to the large and unstable contact resistance.
3. The contact cannot be separated or closed due to the excessive load, or the contact capacity is too small, or the load property changes.
4. The failure of the contact gap re-breakdown occurs because the voltage is too high, or the contact opening distance becomes small.
5. The power supply frequency is too high, or the contact gap capacitance is too large, resulting in failure to accurately break the circuit.
6. Mistakes in contact work due to various environmental conditions not meeting the requirements.
7. Since the arc-extinguishing device or measures are not used, or the parameters are improperly selected, the contacts are worn or unnecessary interference is generated.
(two) coil failure
1. Damage to the insulation of the coil due to changes in the ambient temperature (exceeding the specified values of the technical conditions) causing the coil temperature rise to exceed the allowable value; severe deterioration of the insulation level due to moisture; internal disconnection or inter-turn short circuit due to corrosion.
2. The coil is damaged due to the coil voltage exceeding 110% of the rated voltage.
3. When using the repair, the coil insulation may be damaged due to the damage of the tool, or the wire may be broken.
4. Since the coil voltage is connected incorrectly, if the coil with a rated voltage of 110V is connected to the power supply voltage of 220V, or the AC voltage coil is connected to the same level of DC voltage, the coil is immediately burned out.
5. The AC coil may be burnt out because the coil voltage exceeds 110% of the rated voltage, or the operating frequency is too high, or when the voltage is lower than 85% of the rated voltage, the armature is not attracted.
6. When the AC coil is connected to the voltage, the armature may not be closed and the coil may be burnt out due to the failure or stuck of the transmission mechanism.
(3) Magnetic circuit failure
1. The wear of the corners and the shaft causes the armature to rotate or become stuck.
2. In some DC PILZ safety relays, due to mechanical wear or damage to non-magnetic gaskets, the minimum air gap after the armature is closed becomes small, and the residual magnetism is too large, resulting in failure of the armature to be released.
3. When the PILZ safety relay core breaks the magnetic ring, or the armature and the iron core rust or invade the impurities, the armature will vibrate and generate noise.
4. In the E-type core of the AC PILZ safety relay, when the air gap of the center pillar disappears due to the wear of the iron cores on both sides, the failure of the armature sticking will occur.
(4) Other troubleshooting
If various parts are deformed or loose, mechanical damage, cracking or peeling of the plating layer, insufficient insulation between the live parts and the outer casing, the reaction force spring loses elasticity due to fatigue, various setting values are improperly adjusted, and the product has reached the rated life. .
There are many reasons for the failure of PILZ safety relays. In addition to requiring the manufacturer to ensure the quality of the products, proper use and careful maintenance are also important links to reduce failures and ensure reliable operation.