Over-Speed (Clv); Carrier Frequency; Ground Fault Protection - Hitachi P1 Basic Instruction Manual

OVER-SPEED (CLV)

The over-speed error detection function judges that the speed is excessive if the feedback speed exceeds the over-speed
level. Whether the speed is excessive is determined according to the feedback frequency displayed on [dA-08] Detected
frequency monitor. When the speed has exceeded [bb-80] Over-speed error detection level and [bb-81] Over-speed error
detection time has elapsed, it is judged as an over-speed error. When an over-speed error occurs, the inverter trips with
[E107] Over-speed error.
Function
Over-speed error detection level setting
Over-speed error detection time

CARRIER FREQUENCY

The carrier frequency is the frequency at which the element that controls the inverter output changes. The carrier frequency can be
changed using the [bb101] setting. It is also effective in avoiding resonance of mechanical systems and motors.
If the [AA121] control mode selection is automatic torque boost (03), sensorless vector control (08), zero speed area sensorless vector
control (09), or vector control with encoder (10) set the carrier frequency to 2.1 kHz or higher.
NOTE – Increasing the carrier frequency higher than 5.0 kHz will require the VFD to be de-rated due to thermal increase on the output
transistors. Increasing the carrier frequency will increase the leakage current and appropriate measures should be taken to correct for
the leakage current.
Function
Carrier frequency

GROUND FAULT PROTECTION

This is a function to protect the inverter by the detection of ground faults between the inverter output and the motor at power-on.
The function doesn't work when there is a voltage induced in the motor due to idling or when the inverter trips.
Function
Ground fault protection
Parameter
bb-80
bb-81
Parameter
bb101
Parameter
bb-64
Page 36
Example Value
135%
0.5 sec
Example Value
5.0 kHz
Example Value
0 = disabled
1 = enabled