It is not difficult to want the motor to be lack of phase. As long as you carefully read the three major measures to prevent the motor phase loss, you can avoid the motor phase loss.
It is not difficult to want the motor to be lack of phase. As long as you carefully read the three major measures to prevent the motor phase loss, you can avoid the motor phase loss.
1, circuit breaker
Circuit breakers are used to switch on and off circuits infrequently. When protecting the motor, there are two points that require special attention: 1 its overload capability;
2 Its starting current is very large.
Therefore, when selecting, it is necessary to distinguish the type of motor to be protected. When the protection cage type asynchronous motor is selected, the instantaneous setting current value of the circuit breaker is 8-15 times the rated current of the motor, and the instantaneous setting current value is protected when the wound rotor asynchronous motor is protected. 3-6 times the rated current of the motor, it is strictly forbidden to use the circuit breaker as the operating mechanism for the operation of the electric equipment. In the case mentioned above, the power supply of the fan and the fluorescent lamp is installed with the contactor and the three phases are evenly distributed. The electric equipment was deactivated and the circuit breaker was pulled again, and no disconnection phase loss occurred.
2, fuse
Faulty fuse, install equipment and electrical circuits in strict accordance with the standard.
1 Select the motor that can adapt to the surrounding environment, technically modify the motor that needs frequent forward and reverse starting, and install the delay device to stagger the peak inrush current.
2 non-faulty fuse, in the non-faulty fuse blowing, should be reasonable choice, do not have some misunderstanding, think that can avoid the general starting current, is the best protection of the motor melt standard value, so try to choose close to the motor The standard fuse that starts the current value is actually used to protect the motor from phase-to-phase short-circuit accident or single-phase grounding accident, instead of overload protection of the motor. The overload protection function is caused by heat. The relay is done.
3, contactor
1 Different working system, choose the contactor that matches the capacity of the working system.
Eg: For long-term work, try to choose the contactor of silver alloy or silver-plated contacts. The copper contact should reduce its capacity to less than 50% of the rated capacity of the intermittent long-term working system.
2 The impact of arc energy must be considered when operating frequently. Different environments choose contactors that can adapt to the environment.
Eg: The environment of moisture, corrosive gas, dust, vibration, etc. will rust the iron parts of the contactor, increase the arcing distance between the moving and static contacts, reduce the suction force, cause the jamming phenomenon, the core surface unequal, etc. .
4, thermal relay
Select the matching thermal relay to distinguish the long-term and short-term protection functions. Generally, the voltage is selected from 0.95-1.05 times of the rated current of the motor.
5, the motor
1 Newly purchased motor or newly repaired winding motor, to measure the quality of the winding of the motor, and apply conductive paste between the terminal of the electric machine and the contact surface of the power cord.
2 The resistance values ​​of the three-phase windings of the motor are all equal, especially when the aluminum wire winding is externally connected to the copper terminal, the conductive paste is applied, the oxidation of the aluminum is prevented, and the conductivity is increased, so that the oxide disconnection does not occur. Phase loss.
----- Editor-in-Chief: Dalan Oil Pump Motor 02-Procurement Consultant
Copyright http: / (Dalan Motor) Reprint, please indicate the source
Http://news.chinawj.com.cn Editor: (Hardware Business Network Information Center) http://news.chinawj.com.cn
Safety nets are protective nets installed under or on the side of high-altitude building construction equipment installation or technical performance to prevent accidents caused by falling people or objects. The safety net consists of a net body, side ropes, tethers and tendons. The mesh body is braided with net rope and has diamond or square mesh. Mesh size refers to the distance between two knots adjacent to the knit. The net ropes on the edges around the net body are called side ropes. The size of the safety net (nominal size) is determined by the size of the side rope; the rope that secures the safety net to the support is called a tether. In addition, any rope used to increase the strength of a safety net is collectively referred to as a tendon.
The safety net consists of a net body, side ropes, tethers and tendons. The mesh body is braided with net rope and has diamond or square mesh. The distance between two adjacent knots of a knit is called the mesh size; the net ropes on the edges around the net body are called side ropes. The size (nominal size) of the safety net is determined by the size of the side rope; the rope that secures the safety net to the support is called a tether. In addition, any rope used to increase the strength of a safety net is collectively referred to as a tendon. The safety net material requires small specific gravity, high strength, good abrasion resistance, large elongation and strong durability. In addition, it should have a certain weather resistance, and its strength does not decrease too much after being wet and wet. Safety nets use chemical fibers as the main material. All net ropes on the same safety net must use the same material, and the wet-dry strength ratio of all materials must not be less than 75%. Generally, synthetic chemical fibers such as vinylon and nylon are mostly used as net ropes. Polypropylene is forbidden due to its unstable performance. In addition, as long as it meets the requirements of relevant international regulations, cotton, linen, palm and other plant materials can also be used as raw materials. No matter what material is used, the weight of each safety flat net should generally not exceed 15kg, and it must be able to withstand 800N impact.
Building Safety Mesh,Construction Safety Net,Architectural Safety Net,Architectural Protection Net
Jieyang Xinxin Industry and Trade Co., Ltd. , https://www.gdxxgm.com