There are many types of inverters, which can be divided into voltage type and current type according to the working mode of the main circuit; according to the switching mode, they can be divided into PAM control type, PWM control type and high carrier frequency PWM control type; according to the working principle, It can be divided into V/f control type, slip frequency control type and vector control type, etc.; according to the classification, it can be divided into general type, special type, high frequency type, single phase type and three phase type, etc. Although there are many types, the protection functions are similar. Next, I will introduce these protection functions for you.
1. Overvoltage protection:
The output of the frequency converter has a voltage detection function, and the frequency converter can automatically adjust the output voltage to prevent the motor from overvoltage. Even if the output voltage regulation fails and the output voltage exceeds 110% of the normal voltage, the inverter will stop to protect the motor.
2. Undervoltage protection:
When the motor voltage is lower than 90% of the normal voltage, the inverter protection stops.
3. Overcurrent protection:
When the motor current exceeds 150%/3 seconds of the rated value or 200%/10 microseconds of the rated current, the inverter protects the motor by stopping.
4. Phase loss protection:
monitors the output voltage. When the output phase is missing, the inverter will alarm. After a period of time, the frequency converter will stop protecting the motor.
5. Reverse phase protection:
The frequency converter makes the motor rotate in only one direction, and the direction of rotation cannot be set. The reverse is not possible unless the user changes the order in which motors A, B, C are connected.
6. Overload protection:
The frequency converter monitors the motor current. When the motor current exceeds 120% of the rated current for 1 minute, the inverter protects the motor by stopping.
7. Ground protection:
The frequency converter is equipped with a special ground protection circuit, usually consisting of a ground protection transformer and a relay. When one or two phases are grounded, the inverter will alarm. Of course, if the user needs, we can also design it to stop the protection immediately after grounding.
8. Short circuit protection:
After the output of the inverter is short-circuited, it will inevitably cause overcurrent, and the inverter will stop protecting the motor within 10 microseconds.
9. Overclocking protection:
The inverter has the maximum and minimum frequency limit function, the output frequency can only be within the specified range, and the overfrequency protection function is realized.
10. Stall protection:
Stall protection is usually for synchronous motors. For asynchronous motors, the stall in the acceleration process must appear as overcurrent, and the frequency converter realizes this protection function through overcurrent and overload protection. Stall during deceleration can be avoided by setting a safe deceleration time during commissioning.
There are many types of inverters, which can be divided into voltage type and current type according to the working mode of the main circuit; according to the switching mode, they can be divided into PAM control type, PWM control type and high carrier frequency PWM control type; according to the working principle, It can be divided into V/f control type, slip frequency control type and vector control type, etc.; according to the classification, it can be divided into general type, special type, high frequency type, single phase type and three phase type, etc. Although there are many types, the protection functions are similar. Next, I will introduce these protection functions for you.
1. Overvoltage protection:
The output of the frequency converter has a voltage detection function, and the frequency converter can automatically adjust the output voltage to prevent the motor from overvoltage. Even if the output voltage regulation fails and the output voltage exceeds 110% of the normal voltage, the inverter will stop to protect the motor.
2. Undervoltage protection:
When the motor voltage is lower than 90% of the normal voltage, the inverter protection stops.
3. Overcurrent protection:
When the motor current exceeds 150%/3 seconds of the rated value or 200%/10 microseconds of the rated current, the inverter protects the motor by stopping.
4. Phase loss protection:
monitors the output voltage. When the output phase is missing, the inverter will alarm. After a period of time, the frequency converter will stop protecting the motor.
5. Reverse phase protection:
The frequency converter makes the motor rotate in only one direction, and the direction of rotation cannot be set. The reverse is not possible unless the user changes the order in which motors A, B, C are connected.
6. Overload protection:
The frequency converter monitors the motor current. When the motor current exceeds 120% of the rated current for 1 minute, the inverter protects the motor by stopping.
7. Ground protection:
The frequency converter is equipped with a special ground protection circuit, usually consisting of a ground protection transformer and a relay. When one or two phases are grounded, the inverter will alarm. Of course, if the user needs, we can also design it to stop the protection immediately after grounding.
8. Short circuit protection:
After the output of the inverter is short-circuited, it will inevitably cause overcurrent, and the inverter will stop protecting the motor within 10 microseconds.
9. Overclocking protection:
The inverter has the maximum and minimum frequency limit function, the output frequency can only be within the specified range, and the overfrequency protection function is realized.
10. Stall protection:
Stall protection is usually for synchronous motors. For asynchronous motors, the stall in the acceleration process must appear as overcurrent, and the frequency converter realizes this protection function through overcurrent and overload protection. Stall during deceleration can be avoided by setting a safe deceleration time during commissioning.
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