YASKAWA iQpump1000 User Manual page 169

u
Current Limit
This function provides a current limit of the pump (motor). The function is designed to prevent long-term overload conditions
of the pump, especially if the motor and drive are oversized compared to the pump. The drive will attempt to limit the output
current by reducing the frequency reference. The frequency is reduced using an internal current PI regulator. When the Current
Limit function is active, the alarm "Current Limit Foldback" will be displayed on the HOA keypad. This function will only
operate correctly when the drive is connected to a variable torque motor load such as a centrifugal pump. More specifically,
it will only operate if the load is such that output current increases as output frequency increases (and vice-versa). The current
limit function reduces the pump speed to just above the lower value between the minimum pump speed (P1-06) or the minimum
output frequency. If PI mode is enabled (b5-01 > 0), a special limit will be applied to the PID integrator when output current
limit is active to prevent integrator wind-up.
n Start Up Procedure
1.
Set all other parameters required for the application such as PI control loop, sleep, motor, and I/O parameters
2.
Turn on the current limit function by setting Q3-01 to 1 (enabled). The default setting is 0 (disabled).
3.
Set the desired current limit in Q3-02. This value should not exceed the motor, pump or drive's ratings. This does not
in any way change the motor (oL1) and inverter (oL2) overload functions.
4.
If desired, program a multi-function digital output (H2-oo) to 89 (Output Current Limit) to annunciate the alarm.
n Related Parameters
No.
Q3-01 Output Current Limit Select
Q3-02 Current Limit
H2-oo
Function
Setting
89 Output 1 Limit
The drive displays an alarm on the keypad when the drive is in output current limit.
HOA Keypad Display
Current Limit
Foldback
Cause
Drive output speed is being limited due to
the output current limit.
YASKAWA TOEP YAIP1W 01F YASKAWA AC Drive - iQpump1000 User Manual
Parameter Name
H2 Multi-Function Digital Output Settings
Closed: Drive output speed is being limited due to the output current limit or the single phase foldback
regulator.
Current Limit Foldback
• Reduce the load.
• Verify setting of Q3-02.
• Change to a larger drive size.
4.6 iQpump Presets and Functions
Setting Values
Default: 0
Range: 0, 1
Default: 0.0 A
Minimum: 0.0
Maximum: 1000.0
Description
Minor Fault Name
Possible Solution
4
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