When using inverters, leakage protectors must not be used. This is a major principle of the use of frequency converters.
Some users choose the corresponding leakage protector for the inverter when using the inverter. The result is that the inverter moves together, the leakage protector acts, and the system cannot operate at all. Why?
The principle of the leakage protector is that the zero sequence current is zero. When using the inverter, the zero sequence current cannot be zero.
The output side of the inverter is a PWM wave, and there is a capacitive effect of a long cable between the motor cable and the ground, and the capacitive effect is even more obvious when using a shielded cable. When the inverter is operating, the capacitor is charging and discharging, and the current flows into the ground through the capacitor, and flows back to the inverter from the grounding wire on the incoming side to form a current loop. If a leakage protector is used on the incoming side, it will operate and block the system. So, don't equip your inverter with a leakage protector. If you want to ensure safety, just do a good job of grounding the equipment.
Case: Q: An 18.5KW boiler induced draft fan is installed with an 18.5KW inverter, as soon as the inverter is started, the power distribution room will jump when it is opened, and the power distribution room is equipped with a leakage protector (200mA action, 30mA pulse). The customer was asked to remove the leakage protection was refused, and then the carrier frequency was adjusted to 1KHz, and the starting method of the inverter was still not processed, and the power line of the motor was suspected to have leakage, because its length was about 20 meters and buried in the ground, but it was also difficult for the customer to replace it (its original power frequency was used normally). Is there any simple and effective way to deal with it?
Answer: Since the leakage protector generally detects that the three-phase unbalance degree is more than %20, it will jump protection, and when the inverter is installed, the three-phase unbalance degree will generally exceed %50 or more, so the leakage protector will definitely jump.
Here are a few ways to do it:
Method 1: There will generally be a regulator on the leakage protector, and the regulator can be adjusted to a larger size.
Method 2: Replace the leakage protector with a special leakage protector for the inverter, and there are special leakage protectors for the inverter on the market.
Method 3: Increase the equipment load, that is, the motor load, and the leakage current of the inverter will not be very large when it starts.
Method 4: Short the leakage protector.
|
More on that
|
变频器故障诊断——LS产电
1.如何区分重断层和轻断层
当灯问题时，体系宣布报警信号，毛病指示灯闪烁。当产生严峻毛病时，体系将宣布问题指示灯，问题指示灯将一向亮着，一起宣布分断高压和制止合闸命令，并存储问题 ...
|
|
三相电机电流过高情况——LS产电
一、电源问题
1、电源电压过高
当电源电压过高时，电机反电动势、磁通及磁通密度均随之增大。由于铁损耗的巨细与磁通密度平方成正比，则铁损耗增加，导致铁心过热。而磁通增加，又致 ...
|
|
伺服电机的故障分析——LS产电
1、问题现象：伺服报错OL，伺服电动机不能启动，并有异声毛病剖析及或许产生的原因：
(1)归于电动机自身原因引起的有轴承损坏、异物落人卡住、定子磁铁爆裂掉落或动组织卡住等。
(2) ...
|
|
接触器在工业用电中作用
接触器是工业电顶用按钮来操控其通断的自动开关。接触器由电磁线圈，静衔铁，动衔铁，静触点，动触点和固定支架组成。其原理是当接触器的电磁线圈通入沟通电时，会发生很强的磁场使装在线圈中心 ...
|
|
关于电气设备的介绍——LS产电
依据发电厂和变电站电能的生产、变压、运送、分配和使用的安全、优质、可靠以及经济运转的要求，主要有下列电气设备。
1.一次设备
直接参与生产、 ...
|
|
变频器过载跳闸的原因及检查方法——LS产电
1、变频器过载的主要原因
（1）误动作，变频器内部的电流检测部分产生毛病，检测出的电流信号偏大，导致跳闸。
（2）机械负荷过重，负荷过重的主要特征是电动机发热，并可从显示屏上 ...
|
|
导致电机断轴原因——LS产电
一、装置不当：
电机与所拖动的设备不同心，致使电机承受了过大的径向载荷，终究导致金属疲惫。当电机轴伸端所承受的径向负载太大时，就会造成电机轴在径向上有曲折变形。电机旋转时，轴的 ...
|
|
电动机的维护和保养方法——LS产电
1、看：电动机的正常作业与周围环境有很大的联系。因此每天的巡查过程中，查看电动机周围的漏水﹑滴水状况（会引起电动机的绝缘低而形成击穿以致烧坏），查看电动机外围是否有影响其通风散热环 ...
|
|
变频器自学习电机介绍——LS产电
一、什么是变频器自学习电机？
变频器参数中输入电机铭牌上的(电压，电流，Hz的额定值)然后变频器主动丈量电机的其他参数。
二、变频器为什么要自学 ...
|
|
变频器过压类故障分析方法——LS产电
变频器的过电压会集表现在直流母线的支流电压上.正常状况下,变频器直流电为三相全波整流后的平均值.若以380V线电压计算,则平均直流电压Ud=1.35U线＝513V.在过电压发生时,直流母线的储能电容将被 ...
|
|
通用变频器优点——LS产电
通用变频器的特点是其通用性。跟着变频技能的开展和市场需求的不断扩大，通用变频器也在朝着两个方向开展:低成本的简易型通用LS变频器和高功能多功能的通用变频器。它们别离具有以下特点:
...
|
|
LS产电接触器应用于方面
LS接触器分为交流接触器(电压AC)和直流接触器(电压DC)，它应用于电力、配电与用电。接触器广义上是指工业电中利用线圈流过电流产生磁场，使触头闭合，以达到控制负载的电器。
...
|
|
LS产电假期后变频器上电注意事项
1、假期间低温容易导致设备受潮，查看电气设备是否干燥，有无受潮和结露现象；
2、查看接地线是否松动，线缆是否鼠虫破坏；
3、整理尘埃油污，变频 ...
|
|
电工基础名词解释——产电
1、有功功率——在交流电能的发输用过程中，用于转换成电磁方法的那部分能量叫做有功
2、无功功率——在交流电能的发输用过程中，用于电路内电磁场交流 ...
|
|
简述LS产电ABE203b塑壳断路器
断路器是一种根本的低压电器，断路器具有过载、短路和欠电压维护功用，有维护线路和电源的才能。断路器在用电安全上是一款必不可少的产品。因应用不同有塑壳断路器、框架断路器、微型断路器等分 ...
|
|
PLC技术掌握的五个阶段
一.逻辑阶段
所谓的逻辑阶段就是能够完结继电体系中的一般逻辑性规划，既然是继电体系所以电力拖动知识就是该阶段的根底。我个人总结学习继电体系的根在于一个字“抢”，继电体系之 ...
|
|
LS产电接线端子故障
接线端子从运用角度讲，应该达到的功用是：接触部位该导通的地方有必要导通，接触牢靠。绝缘部位不应导通的地方有必要绝缘牢靠。接线端子常见的致命故障形式有以下三种：
...
|
|
Grounding of the secondary side of the voltage transformer and the current transformer - power generation
1. The transformer is grounded twice
It refers to the grounding of the S2 terminal of the current transformer or the ground of the n terminal of the voltage transformer. As long as the single point is grounded, because the transformer is blocked between the second and the first, before grounding, the secondary winding has no potential connection with the ground, after grounding, the transformer ...
|
|
变频器维修故障处理方法——LS产电
1、没有显现。这种状况是比较常见的，一般在外部三相电源正常状况下，是变频器的开关电源烧了，能够丈量一下变频器端子输出板子上的24伏电源，假如没有，便是这个问题了，这种状况一般是开关管 ...
|
|
产电交流接触器的选型原则与选型要点
1、接触器的线圈电压，一般应低一些为好，这样对接触器的绝缘要求能够下降，运用时也较安全。但为了方便和削减设备，常按实际电网电压选取。
2、电动机的操作频率不高，如压缩机、水泵、风 ...
|
|
Contact
working hours
