Troubleshooting methods for hydraulic testing machines

Hydraulic material testing machine is one of the commonly used equipment for measuring the mechanical properties of materials. Hydraulic testing machine is mainly used for tensile, compressive, bending, shear and other tests of metals and non metals. It can be widely used in building materials, metallurgy, scientific research institutions, colleges and universities, quality inspection centers and commodity inspection departments. It is an ideal testing equipment for industries such as production, scientific research and teaching.

Fault one
The load cannot be sustained. The reasons for this phenomenon are multifaceted:
1. Hydraulic oil viscosity is too low.
2. There is air present in the hydraulic system.
3. Hydraulic system leaks oil or the return valve is not tightly sealed.
4. The stabilizing spring inside the oil delivery valve has just passed through and is small;
5. There are impurities and foreign objects inside the oil delivery valve.
Exclusion method: Firstly, exhaust the air in the hydraulic system to solve the oil leakage problem. If there is a lot of hydraulic oil overflowing around the piston, reflect on the conductivity of the overflow pipe. Secondly, reflect on the viscosity of the hydraulic oil and dispose of it according to the situation. If there is no oil leakage after disposal or oil change but the load still cannot be sustained, the oil delivery valve should be cleaned and the stiffness of the stabilizing spring inside the valve should be added.
Fault 2
Unable to add load, or unable to add the maximum load.
1. The oil pump belt is loose and there is a slipping phenomenon.
2. The oil pump cannot function properly.
3. There is a lack of oil storage in the fuel tank.
4. Hydraulic oil viscosity is too low.
5. The hydraulic system is experiencing oil leakage.
6. The stiffness of the stabilizing spring inside the oil delivery valve is insufficient.
7. There is a blockage in the saving needle hole inside the oil delivery valve.
Troubleshooting: Firstly, check if the high-pressure oil system is leaking oil, if the oil storage in the tank is sufficient, and if the oil pump belt is loose. Secondly, check if the return oil volume of the return pipe increases when the oil pressure rises (which should remain unchanged or decrease under normal conditions). Then, check if the oil delivery valve, oil pump, etc. are functioning properly and solve the problem according to the situation.
Fault Three
Abnormal noise from the motor part.
1. A three-phase circuit has one phase missing;
2. The transmission mechanism causes an increase in motor load.
Fault 4
The motor is overheating and scalding.
1. There is a short circuit in the motor winding;
2. Motor overload;
3. The motor is damp.
Fault 5
Sudden power outage.
1. There is a short circuit in the electrical system;
2. Poor contact of electrical switch.
Fault 6
The hydraulic testing machine always breaks the specimen on both sides during tensile testing. The reason for this phenomenon should first consider whether the installation of the main body of the testing machine is vertical. If this reason is eliminated, it should be eliminated from the following three aspects.
1. The jaws were not properly aligned during clamping, and the specimen should be clamped symmetrically according to the requirements.
2. Poor quality of the jaws and damaged teeth not only affect the misalignment of the jaws, but also cause the specimen to slip during the testing process, making it difficult to identify the yield point. At this point, the jaws should be replaced.
3. The adjustment of the lifting guide wheel is not correct, causing the upper and lower jaws to be misaligned. An inspection rod should be processed, and after tightening the upper and lower jaws, two force columns should be used as a basis to measure with a dial gauge until the adjustment is qualified.