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Why the use of frequency converter can not use the leakage protector?
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Why the use of frequency converter can not use the leakage protector?In life and production, often use the leakage switch, but inverter that sometimes use not, most manufacturers in the workshop installation switch is often used leakage switch as main switch. When using the frequency conversion control, the problem comes out, the leakage switch with a little time. Always tripping.
Personal experience is that when installed with inverter machine to remove leakage or separate the MCCB, lest switch tripping. Cause false action!
Use transducer selection of leakage current is 30mA anticreeping switch, leakage switch can not as a function of protection of personal safety, the inverter is the main reason for existence leakage current will cause maloperation of inverter, if must be installed leakage switch, the choice of the 100 MAS of leakage current to prevent line insulation damage in the event of fire.
When using frequency converter, the leakage protection device must not be used. This is a big principle for the use of frequency converter.
Some customers in the use of inverter, the inverter for the corresponding leakage protection. The final result is: the inverter together, the leakage protector is the movement, the system simply can not run.
Why?
The principle of leakage protection is that the zero sequence current is zero. And the use of inverter, the zero sequence current can not be zero.
Inverter output side for the PWM wave, the electric cable and the earth between the long cable capacitance effect, using a shielded cable, the capacitor effect is more obvious. In the converter work, capacitance in the charge and discharge, current through the capacitor into the earth, and from the line side grounding wire and then flows back into the inverter to form an electrical circuit. If the use of leakage protection device in the line side, then it will act, cut off the system operation.
SO, don't match the leakage protector for your converter. If you want to ensure that the security, do a good job on the line.
双语对照
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