Danfoss VLT No Flow Feature Fact sheet

Fact Sheet

VLT® No Flow Feature

The VLT® AQUA Drive provides a new No Flow detection feature for pump systems. This feature is useful for detecting conditions where a pump is producing no flow – a condition that can cause pump damage if not detected and corrected.

No flow based on motor power and frequency

No Flow Detection is based on the measurement of power at specific motor speeds. The drive monitors actual power and motor frequency and compares it to the calculated no-flow power at specific speeds. If the power

measured at a specific frequency is greater than the no-flow power calculated by the drive, the pump is producing flow. If the power measured is less than the no-flow power calculated by the drive, a warning or alarm is generated to notify the operator of the condition.

The perfect solution for

nIntelligent control

nWater and wastewater system protection

nRemote status reporting

To determine the no-flow power level throughout the speed range, the drive generates a power vs. frequency curve that represents the no-flow condition. This curve is generated by the drive from two data points. These power/ frequency points can be entered into the drive automatically or manually.

Manual or Auto Set Up are available

The Auto Set Up automatically steps the user through the commissioning process, storing the data measured.

When the automatic set-up is selected

Feature

Eliminates an external differential pressure switch or flow meter

Eliminates wiring for external sensors

A warning or alarm can alert operator of the problem

Programming is quick and easy with pre-programmed software

the output frequencies used are 50% and 85% of maximum. Manual set-up can be used when a different pair of frequencies is desired.

Programming is quick and easy

The drive software makes programming the No Flow feature quick and easy by choosing Pump Functions and then No Flow Function under the Quick Menu.

Benefit

Reduce installation and maintenance cost

Reduce installation and maintenance cost

Provides proper operation of equipment and increases occupant comfort

Saves time and increases reliablity

www.vlt-drives.danfoss.com

Programming No Flow detection

Programming for No Flow detection is simplified with a number of para-

meters that are pre-programmed into the drive. Prior to programming this feature, commission the drive by using

the parameters in the Quick Menu. Then perform the following steps for programming No Flow detection:

				Settings
	Par.#	Description			Comments
			Factory	Recommended setting
			setting
	1-00	Configuration mode		Open loop	VLT® AQUA Drive must be set in Open Loop for Auto Set-up.
	22-20	Low Power Auto Set-up	Disable	Enable	Close the outlet valve for the pump before starting Auto Set-up.
					Select Enable and follow the instruction on the LCP. After Auto Set-up
					is complete, open the pump outlet valve.

The following parameters are accessed through the Main Menu and will be stored after pressing the [OK] key to save the results after the auto-tuning:

22-33	Low Speed			When Low Power Auto Set-up is used, 50% of the drive’s
	[Hz]			maximum frequency will be stored here. This can be
				manually edited, if desired.
22-34	Low Speed Power [kW]			When Low Power Auto Set-up is used, the output power
				measured under no flow conditions at 50% speed will be
				stored here. This can be manually edited, if desired.
22-37	High Speed			When Low Power Auto Set-up is used, 85% of the drive’s
	[Hz]			maximum frequency will be stored here. This can be manually edited,
				if desired.
22-38	High Speed Power [kW]			When Low Power Auto Set-up is used, the output power
				measured under no flow conditions at 85% speed will be
				stored here. This can be manually edited, if desired.
1-00	Configuration mode	Open loop	Closed loop	Return the VLT® AQUA Drive to Closed Loop operation if required.

These parameters are used after Auto Set-up and the No Flow feature is operating:

22 - 30	No Flow Power			When the drive is running, this parameter will show the power
				level that will be interpreted as producing no flow at the current
				motor speed.
22 - 31	Power Correction Factor	100%	110%	This parameter is used to raise or lower the no flow power curve
				to the percentage entered here. Values above 100% help ensure the
				drive reliably detects no flow.

The following parameters determine the action that the drive will take if a no flow condition is detected:

22-21	Low Power	Disable	Enable	To activate no flow based on power
	Detection
22-23	No Flow Function	Off	Sleep Mode/Warning/Alarm	Select action
22-24	No Flow Delay	10 sec.		Set the time delay before the drive will perform the No Flow Function.
				Generally set longer than the decel ramp time.

The following parameters give an indication to a SCADA system if a no flow condition is detected:

5-40	Function Relay		[190] No Flow	Program one of the relays to selection [190], No Flow.
				The selected relay will be activated when No Flow occurs.
	Digital Output		[190] No Flow	A digital output can be used to indicate a no flow condition. Use the
				parameter that sets the function of the desired digital output.

The following are used if No Flow is reported via serial communications:

	Protocol	Alarm Word	Warning Word
	Profibus/Profinet	Parameter 1691 bit 5=1	Parameter 1693 bit 5=1
	DeviceNet/Ethernet IP	Class 116, Instance 1, Attribute 193, bit 5=1	Class 116, Instance 1, Attribute 193, bit 5=1
	Modbus RTU/TCP	Register 16910 Bit 5=1	Register 16930 Bit 5=1

Danfoss Drives, Ulsnaes 1, DK-6300 Graasten, Denmark, Tel. [phone], Fax [phone], www.vlt-drives.danfoss.com, E-mail: [e-mail]

DEDD.PFF.400.A2.02

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