YASKAWA iQpump Series

158 YASKAWA TM.iQp.02 iQpump Drive Programming Manual
◆ P4 Pump Protection
■ P4-01 Pre-Charge Level
Setting Range: 0.0 to 6000.0
Factory Default: 0.0
The iQpump drive can be configured for special functions for dedicated pumping applications. These functions are: Pre-Charge Level
(P4-01) and Thrust Bearing Frequency (P4-05). Refer to the Thrust Bearing Frequency (P4-05) for further description about the thrust
bearing function. There are two pre-charge operation methods: (1) Pre-charge with Thrust Bearing function disabled. (2) Precharge and
Thrust Bearing functions both enabled.
Some pump systems require the system to be “pre-charged” before normal operation can occur. The built-in pre-charge function allows
the pump system to run at a fixed motor speed for a programmed time. This function also operates in conjunction with a programmable
feedback level and/or an external contact to indicate that the desired level has been reached.
Pre-Charge with Thrust Bearing Function Disabled.
The pre-charge level that the iQpump drive will operate at is determined by programming the Pre-Charge Level (P4-01). The drive will
monitor the Feedback Level (U1-91) and compare the feedback level with the level programmed in the Pre-Charge Level (P4-01). When
the feedback level reaches the Pre-Charge Level (P4-01), the drive will disable the pre-charge mode and switch to Auto Mode or
automatic regulation.
The frequency reference used during the pre-charge mode is determined by programming Pre-Charge Frequency (P4-02) for a maximum
allowable time set in the Pre-Charge Time (P4-03).
A multi-function digital input can be programmed to indicate the pre-charge has been completed, “Low Water Level” (H1-xx = 85), with
Low Water Input (P1-15) determining if the low water detection is a normally-open or normally-closed contact.
The pre-charge can also be disabled by programming the multi-function digital input for Pre-Charge Disabled (H1-xx = 84).
The pre-charge is only active in Auto Mode. The Pre-Charge Level (P4-01) works in conjunction with the Pre-Charge Frequency (P4-02)
and the Pre-Charge Time (P4-03). The units for this parameter are determined by the System Units (P1-02).
Note: The drive will stop when one of the following conditions occur:
• The feedback level rises above the Pre-Charge Level (P4-01)
• The Pre-Charge Time (P4-03) elapses, or
• The Low Water Level input (H1-xx = 85) is deactivated
The acceleration time used during pre-charge mode is determined by Acceleration Time 1 (C1-01).
If the Pre-Charge Frequency (P4-02) is less than the Minimum Pump Frequency (P1-06), the drive will internally use a Pre-Charge
Frequency equal to the Minimum Pump Frequency (P1-06) value.
The pre-charge function can only be activated while the drive is in “stop” condition. To enable the pre-charge function requires the Pre-
Charge Time (P4-03) and Pre-Charge Level (P4-01) to be set to a value greater than 0. When the pre-charge function is activated, a “Pre-
Charge” alarm will be displayed on the digital operator.