If The Slip Compensation Function Has Low Speed Precision; If There Is Low Speed Control Accuracy At High-Speed Rotation In Open-Loop Vector Control Method; If Motor Deceleration Is Slow - YASKAWA Varispeed G7 Series Instruction Manual

The analog frequency reference bias setting is wrong (the gain setting is wrong).
The frequency reference bias set in constant H3-03 is added to the frequency reference. Check to be sure that
the set value is suitable.
A signal is being input to the frequency reference (current) terminal A2 or A3.
When 0 (Add to terminal A1) is set for constant H3-09 (Multi-function Analog Input Terminal A2 Function
Selection) or H3-05 (Multi-function Analog Input Terminal A3 Function Selection), a frequency correspond-
ing to the terminal A2 or A3 input voltage (current) is added to the frequency reference. Check to be sure that
the set value and analog input value are suitable.


If the Slip Compensation Function Has Low Speed Precision

If speed control accuracy is low for the slip compensation function, the slip compensation limit has been
reached. With the slip compensation function, compensation cannot be carried out beyond the slip compensa-
tion limit set in constant C3-03. Check to be sure that the set value is suitable.

If There is Low Speed Control Accuracy at High-speed Rotation in Open-
loop Vector Control Method
The motor's rated voltage is high.
The Inverter's maximum output voltage is determined by its input voltage. (For example, if 200 VAC is input,
then the maximum output voltage will be 200 VAC.) If, as a result of vector control, the output voltage refer-
ence value exceeds the Inverter output voltage maximum value, the speed control accuracy will decrease. Use
a motor with a low rated voltage (i.e., a special motor for use with vector control), or change to flux vector
control.


If Motor Deceleration is Slow

Use the following information when the motor deceleration is slow.
The deceleration time is long even when braking resistor is connected.
The following causes are possible.
"Stall prevention during deceleration enabled" is set.
When braking resistor is connected, set constant L3-04 (Stall Prevention Selection during Deceleration) to 0
(disabled) or 3 (with braking resistor). When this constant is set to 1 (enabled, the factory setting), braking
resistor does not fully function.
The deceleration time setting is too long.
Check the deceleration time setting (constants C1-02, C1-04, C1-06, and C1-08).
Motor torque is insufficient.
If the constants are correct and there is no overvoltage fault, then the motor's power is limited. Consider
increasing the motor capacity.
Troubleshooting
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