The main reason for the reduction of vacuum degree of vacuum measuring instrument

　　1. The influence of contact stroke. For the arc extinguishing chamber of various types of 10kv vacuum measuring instruments currently produced, the overstroke of the contact is about 4mm according to regulations, and the opening distance is about 11mm. When installing or repairing the vacuum measuring instrument, it should be accurately measured according to the contact stroke requirements in the product installation manual, and the pull rod should be adjusted to prevent excessive stroke. The vacuum measuring instrument should carefully check the circuit stroke, stroke and contact opening distance of the circuit breaker during the annual maintenance. In actual operation, there is no shortage of improper adjustment of the circuit breaker overstroke. During the closing process of the circuit breaker, there are accidents such as the rupture of the arc extinguishing chamber and the deformation of the conductive rod due to mechanical impact. The current transformer tester is a variety of effective loads specially provided when testing current transformers. It is an ideal product for on-site transformer automatic transformer calibrator testing.

　　2. The effect of bounce. The contacts of vacuum gauges are mostly flat docking structures, and different degrees of bounce are inevitable during the opening and closing operations. Bounce or bounce will cause damage to the operation: the bellows may be subjected to forced vibration, which may cause cracks and lead to chute leakage; when the switch is closed, the contact speed of the circuit breaker is high, and the impact force at the end of the action is high and large, causing rebound, which may cause deformation of the contacts and conductive rods, or even rupture; if bounce occurs, the vacuum gauge that cuts open the capacitor bank may damage the capacitor. Therefore, some vacuum gauge manufacturers have noticed the damage caused by the bounce of the vacuum gauge and introduced the so-called "bounce-free" vacuum gauge, which greatly reduces the mechanical shock of the circuit breaker during opening and closing by mechanical means, buffering.

　　3. The influence of the closing speed of the circuit breaker. The closing and closing speed of the circuit breaker play a certain role in the arc extinguishing of the vacuum measuring instrument, and also determine the service life of the vacuum measuring instrument. Therefore, the closing speed of the circuit breaker should be measured before commissioning, and product quality and commissioning problems should be discovered in time. On the one hand, it prevents the opening and closing speed from being too high, and the mechanical collision is strong when the contact of the circuit breaker ends, which causes more violent vibration in the arc extinguishing chamber.

　　4. Regarding the impact on the buffer, the buffer stroke should be carefully checked. There should be no deformation, damage or excessive compression. A buffer margin must be left. For part of the oil-filled buffer, the oil level of the buffer should be checked regularly and the oil should be replenished in time.

　　5. Affected by the capacity of the operating mechanism, some circuit breakers are also equipped with a "permanent magnetic operating mechanism". When configuring different types of operating mechanisms, during installation or modification, attention should be paid to the operating distance of the operating lever. If the capacity is too large, it will have a serious impact on the arc extinguishing chamber and damage the bellows of the vacuum arc extinguishing chamber, directly affecting the vacuum. The service life of the circuit breaker is accelerated by the vacuum degree of the circuit breaker.