How to Use a Multimeter to Measure the Quality of Three-phase Water Pumps 1. Measure the motor winding resistance: Use a multimeter resistance to measure the resistance of the motor winding. If it is a three-phase motor, measure the three-phase coil resistance separately. The resistance is normal in tens of euros to 1,000 euros, and the three groups of three-phase motors are close to normal. The purpose of the measurement is to measure the quality of the windings in the motor windings, determine whether there are burned coils, or shorts between the motor slots.
2. Measure the insulation of the motor windings: Use a multimeter 10k to measure the motor coil and the housing resistance. If it is a three-phase motor, it is necessary to measure the resistance of the three groups of coils and the casing separately. One end of the multimeter is connected to the coil outlet, and the other end is connected to the motor housing. The resistance value is above 1M Europe (low power above 0.5M Europe) is normal. The purpose of the measurement is to check if the insulation of the motor to the housing is good.
Use of water pump Practical application:
Widely used in shipbuilding, oil extraction, loader, etc. In 2008, the production of ships reached 15,000 tons, which accounted for 21% of the world market. By 2015, it will become the world's largest shipbuilding country. In order to guarantee the normal sailing or mooring of the ship and satisfy the life requirements of the crew and the passengers, each ship must be equipped with a certain number of marine pumps that can play a corresponding role. The marine pump is one of the important auxiliary machines. According to incomplete statistics, the total number of marine pumps of various types and purposes in various types of marine auxiliary machinery and equipment accounts for approximately 20%-30% of the total number of marine machinery and equipment, and the price of marine pumps is in the cost of marine equipment. The proportion is also relatively large. In the total cost, the marine pump accounts for about 4%-8% of the cost of the ship's equipment. Under normal circumstances, the procurement of a marine pump for a medium-sized ship or more can reach more than 10 million yuan. When it comes to the key pump market, we must say that China has completed the "West-East Gas Pipeline" project, and "West-East Gas Pipeline Project" also needs pump products. At the same time, the country must also build other pipelines for natural gas transmission. In these projects, a large number of pump products are also required.
Different uses:
Pumps have different uses, different transport liquid media, different flow rates, different ranges of lift, therefore, its structure is certainly not the same, the material is also different, summed up, can be roughly divided into:
1. Urban water supply 2, sewage system 3, civil engineering, construction system 4, agricultural water conservancy system 5, power station system
6. Chemical system 7, petroleum industry system 8, mine metallurgy system 9, light industrial system 10, ship system
How to choose a pump The flow rate of the water pump, that is, the amount of water discharged, should generally not be selected too large, otherwise it will increase the cost of purchasing the water pump. Should be selected according to need, such as self-priming water pump used by the user's home, the flow should be selected as small as possible; if the user is using a submersible pump for irrigation, the flow rate can be appropriately selected.
1) It is necessary to purchase water pumps according to local conditions. There are three types of commonly used agricultural pumps, namely centrifugal pumps, axial pumps and mixed-flow pumps. The centrifugal pump has a high lift, but the output is not large, and it is suitable for mountainous areas and well irrigation areas. The axial pump has a large amount of water, but the lift is not too high. It is suitable for use in plain areas; the output and head of the mixed-flow pump are between centrifugal pumps. Between axial and axial pumps, suitable for use in plains and hills. The user should purchase according to the local conditions, water source and lifting height.
2) The water pump should be properly selected. After determining the type of pump, it is necessary to consider its economic performance, paying particular attention to the selection of the head and flow rate of the pump and its supporting power. It must be noted that there is a difference between the head (total head) specified on the pump label and the outlet head (actual head) when used. This is due to a certain resistance loss when the water passes through the water pipe and near the pipeline. Therefore, the actual head will generally be 10%-20% lower than the total head, and the water output will be reduced accordingly. Therefore, in actual use, only 80% to 90% of the lift and flow rate indicated by the signage can be estimated. The choice of the pump's supporting power can be selected according to the power indicated in the signboard. In order to make the water pump start quickly and use safety, the power machine The power can also be slightly larger than the required power of the pump, generally about 10% higher; if there is power, when purchasing the pump, the power pump can be selected according to the power of the power machine.
3) We must strictly purchase water pumps. When purchasing, it is necessary to verify the "three certificates", that is, agricultural machinery promotion licenses, production licenses, and product inspection certifications. Only the three certificates Qifang can avoid the purchase of eliminated products and inferior products.
Three-phase submersible pump wiring diagram
