Protections of Motor by Variable Frequency Drive
Over-voltage Protection
Output of the variable frequency drive has the voltage detection function, and the VFD can automatically adjust the output voltage, so as to ensure the motor not to withstand over voltage. Even if the output voltage adjustment fails and the output voltage exceeds 110% of the normal voltage, the VFD will protect the motor by stopping the machine.
Low-voltage Protection
When the motor voltage is below 90% of the normal voltage, the VFD shuts down for protection.
Over-current Protection
When the motor current exceeds 150% of the rated value for 3 seconds or 200% of the rated current for 10 microseconds, the variable frequency drive protects the motor by shutting down.
Phase Lost Protection
VFD can monitor the output voltage. When the output lacks phase, the VFD alarms. After a period of time, the VFD protects the motor by shutting down.
Phase-reversal Protection
VFD makes the motor to rotate in only one direction. Unless the user changes the phase sequence of connection A, B and C of the motor, otherwise there is no possibility of inversion.
Overload Protection
The variable frequency drive monitors motor current. When the motor current exceeds 120% of rated current for 1 minute, the converter protects the motor by shutting down.
Ground Protection
VFD is equipped with a special grounding protection circuit, which is generally composed of grounding protection transformer and relay. When one or two phases are grounded, the VFD alarms. In case the user requires, the VFD can also be designed for protecting the motor by shutting down immediately as soon as it grounds.
Short-circuit Protection
After the VFD output is short circuited, it will inevitably cause overcurrent. In 10 microseconds, the VFD protects the motor by shutting down.
Over-frequency Protection
The VFD has the function of maximum and minimum frequency limit, so that the output frequency can only be within the prescribed range, thus realizing the function of over-frequency protection.
Stall Protection
Stall protection is generally suitable for synchronous motors. For asynchronous motors, the stall in acceleration process is bound to be over-current, and the VFD realizes this function by over-current and overload protection. Stall during deceleration can be avoided by setting a safe deceleration time during debugging.
Output of the variable frequency drive has the voltage detection function, and the VFD can automatically adjust the output voltage, so as to ensure the motor not to withstand over voltage. Even if the output voltage adjustment fails and the output voltage exceeds 110% of the normal voltage, the VFD will protect the motor by stopping the machine.
Low-voltage Protection
When the motor voltage is below 90% of the normal voltage, the VFD shuts down for protection.
Over-current Protection
When the motor current exceeds 150% of the rated value for 3 seconds or 200% of the rated current for 10 microseconds, the variable frequency drive protects the motor by shutting down.
Phase Lost Protection
VFD can monitor the output voltage. When the output lacks phase, the VFD alarms. After a period of time, the VFD protects the motor by shutting down.
Phase-reversal Protection
VFD makes the motor to rotate in only one direction. Unless the user changes the phase sequence of connection A, B and C of the motor, otherwise there is no possibility of inversion.
Overload Protection
The variable frequency drive monitors motor current. When the motor current exceeds 120% of rated current for 1 minute, the converter protects the motor by shutting down.
Ground Protection
VFD is equipped with a special grounding protection circuit, which is generally composed of grounding protection transformer and relay. When one or two phases are grounded, the VFD alarms. In case the user requires, the VFD can also be designed for protecting the motor by shutting down immediately as soon as it grounds.
Short-circuit Protection
After the VFD output is short circuited, it will inevitably cause overcurrent. In 10 microseconds, the VFD protects the motor by shutting down.
Over-frequency Protection
The VFD has the function of maximum and minimum frequency limit, so that the output frequency can only be within the prescribed range, thus realizing the function of over-frequency protection.
Stall Protection
Stall protection is generally suitable for synchronous motors. For asynchronous motors, the stall in acceleration process is bound to be over-current, and the VFD realizes this function by over-current and overload protection. Stall during deceleration can be avoided by setting a safe deceleration time during debugging.
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