If The Motor Operates At Higher Speed Than The Frequency Reference; If There Is Low Speed Control Accuracy Above Base Speed In Open Loop Vector Control Mode; If Motor Deceleration Is Slow - Omron VARISPEED F7 User Manual

If the Motor Operates at Higher Speed than the Frequency Reference

PID control is enabled.
If the PID control is enabled (b5-01 = 1 to 4), the Inverter output frequency will change to regulate the process
variable to the desired set point. The PID can command a speed up to Maximum Output Frequency (E1-04)
even though the reference is much lower.
If There is Low Speed Control Accuracy Above Base Speed in Open Loop
Vector Control Mode
The Inverter's maximum output voltage is determined by its input voltage. (For example, if 400 VAC is input,
then the maximum output voltage will be 400 VAC). Vector control uses voltage to control the currents within
the motor. If the vector control voltage reference value exceeds the Inverter output voltage capability, the
speed control accuracy will decrease because the motor currents cannot be properly controlled. Use a motor
with a low rated voltage compared to the input voltage, or change to Closed Loop Vector control.

If Motor Deceleration is Slow

The following causes are possible:
The deceleration time is long even when braking resistor is connected.
The following causes are possible:
Stall Prevention During Deceleration is enabled.
When a braking resistor is connected, set parameter L3-04 (Stall Prevention Selection during Deceleration) to
0 (disabled) or 3 (with braking resistor). When this parameter is set to 1 (enabled, factory default), the stall
prevention function will interfere with the braking resistor.
The deceleration time setting is too long.
Check the deceleration time setting (parameters C1-02, C1-04, C1-06, and C1-08).
Motor torque is insufficient.
If the parameters are correct and there is no overvoltage fault, then the motor's power may be insufficient.
Consider increasing the motor and Inverter capacity.
The torque limit has been reached.
When a torque limit is reached (L7-01 to L7-04), the motor torque will be limited. This can cause the deceler-
ation time to be extended. Check to be sure that the value set for the torque limit is suitable.
If a torque limit has been set for the multi-function analog input terminal A2 Function (parameter H3-09 = 10
to 12 or 15), check to be sure that the analog input value is suitable.
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