Vacuum pump motor is the core part of vacuum pump. In order to better use the vacuum pump, we need to have a certain understanding of its working principle. Let’s have a brief introduction to it.
Brief introduction of factory power supply and vacuum pump motor
The voltage of three-phase AC power supply in China is generally 380V. In order to prevent the line loss in the process of transmission and distribution, the voltage from the transformer to the factory is generally 400V, which is normal.
Generally speaking, the power supply line of the factory is three-phase four wire system, which is compatible with three-phase power production and single-phase power lighting.
For example, a three-phase motor can be connected to three phase lines, and a single-phase load such as lighting and household appliances can take over the phase line and zero line to obtain a single-phase power supply. For special equipment such as welding machine, two phase lines can also be used to obtain two-phase power supply
In China, the frequency of three-phase alternating current is 50Hz, which means that the voltage changes 50 times per second according to the sine law. The direction of three-phase asynchronous motor is directly related to the phase sequence. The steering direction of vacuum pump is determined and cannot be reversed, so the phase sequence must be accurate. Reversing will damage the vacuum pump.
The rotary vane vacuum pump is equipped with AC motor, mainly three-phase asynchronous motor and single-phase asynchronous motor. Generally, motors below 4kw are connected with star (220 / 380V), and motors above 4kw are connected with triangle (380 / 660V). However, this is not necessarily absolute, it must be wired according to the identification on the motor nameplate.
When the motor is running, due to the copper loss and iron loss caused by the coil and iron core, as well as the heat generated by mechanical friction, the motor will inevitably generate heat. When the heat cannot be dissipated in time and the temperature of the coil exceeds the maximum temperature that the coil insulating material can bear, the insulating material will age and become fragile, and finally the insulation will be damaged until the coil is burnt.
How to match the vacuum pump and motor? This calculation: shaft power = 1.732 * 380V * 9 * 0.81* 0.001 = 4.798kw type: 380V voltage, current 0.81 power due to the power consumption of several shafts has been notified according to the above calculation, then how big should the actual matching motor be? Calculation: 4.798/0.85 (motor efficiency) = 5.644kw, but in fact, the standard motor of ZD is 5.64kw, 5.5kW and 5.5kW, so I chose. It should be pointed out that the efficiency of the motor is calculated directly according to the efficiency of 0.85, and the efficiency of the purchased motor should be guaranteed. Finally, we need to pay attention to speed. Finally, there is a key point that your motor may be suitable, but because you will use a vacuum that exceeds its rated pressure, the current will rise to solve the problem of the suction port by opening a port for air suction – perhaps in order to reduce the pump load, the current of the motor will stabilize. The normal working current of standard 4kw motor is about 6.3A
Measures to prevent motor from burning out
1. All electrical work must be carried out by a professional electrician
2. Check the rated voltage and frequency of the motor. Check the wiring on the nameplate carefully. If it cannot be confirmed, connect it to the star, start without load, and gradually increase the load to check the current, etc.
3. The ambient temperature of the vacuum pump should preferably be lower than 40 ° C to maintain good ventilation.
4. According to the operating instructions of vacuum pump, timely and correct maintenance shall be carried out.