VSD Dry Run Protection Setup
To setup a Low Current Alarm (typically used for Dry Run Protection for Water Pumps), various options exist as follows:
Option 1: Basic Low Current Detection Trigger Setup.
This is used to detect a low current for a specified duration, after which a fault alarm will be triggered. Set the following parameter settings:
- Set bb-14 = 1 (Off Load Protection Enabled)
- Set bb-15 = set as % of motor rated current (d0-02) – this is to define the dry run current value to be used as trigger (Dry Run Current)
- Set bb-16 = delay protection time – this is to define for how long the current value can be below the Dry Run Current (Low Current) before initiating a trigger event
When the Low Current Alarm is triggered the VSD will show Err30. In some cases it might be required to set the VSD to automatically restart again after a delay period. This requires that the VSD is set up to clear the Error to allow the Auto Restart. This can be done as described in the following FAQ entry HERE.
Option 2: End Of Curve settings, ideal for scenarios where a PID (Constant Water Pressure Setup) is used.
End of Curve Parameter settings for pump systems are used to detect leaks/breaks in the system which can cause damage if not detected and corrected promptly. End of Curve detection is based on the measurement of the feedback pressure and the speed of the motor. If there is a leak/break in the system, pressure will decrease and the pump will accelerate to try and increase the system pressure to the desired pressure. When the drive is running at maximum speed with a feedback signal less than a specified % (C0-25) of the set point pressure (expected pressure) for a specified time period (C0-26), a fault alarm is initiated (Err31).
This is used to detect low pressure at full speed or whether the PID signal is lost. Example:
- Set C0-25 = 97 %
- Set C0-26 = 15 sec
When it is detected that the PID feedback is less than 97% the expected feedback for time period exceeding 15 seconds, the VSD will stop and display fault alarm Err31.
Option 3: Using Virtual Digital Output. Set the following parameter settings:
- Set b7-00 (VDI1) = 38 (Normally Open input of external fault – this is to specify the Virtual Digital Input to give an Error when triggered by the Virtual Digital Output) – the default for b3-04 = 38 and first needs to be set to a different value to allow setting b7-00 = 38 – only one terminal can use a value at a time)
- Set b7-11 (VDO1) = 26 (Zero current state – this is to set the Virtual Digital Output to trigger a zero current state output)
- Set b4-31 (Zero current detection level) = set below current value (% of motor current as set using d0-02) – this is to define the current value to be used as the Zero Current (Low Current) trigger
- Set b4-32 (Zero current detection delay time) = delay protection time – this is to define for how long the current value can be below the Zero Current (Low Current) before initiating a trigger event
When the Low Current Alarm is triggered the VSD will show Err15: External Equipment Fault (External fault signal via virtual I/O). In some cases it might be required to set the VSD to automatically restart again after a delay period. This requires that the VSD is set up to clear the Error to allow the Auto Restart. This can be done as described in the following FAQ entry HERE.
* Please Note: For VSDs up to 55kW using software versions before V0.12 (released 15 Sept 2022), the B4-31 current value of 10% = d0-02, for version V0.12 and later the B4-31 current value of 100% = d0-02 for all VSD kW ranges.
For scenarios where these setups might be applicable, please see:
– To set up a EMHEATER VSD with a Pressure Transmitter to provide Constant Water Pressure using the VSD Parameters to set a Fixed Target Pressure, please see the relevant FAQ entry HERE.
– To set up a EMHEATER VSD with a Pressure Transmitter to provide Constant Water Pressure using an external analog signal (such as a PLC) to modify the target pressure (Variable Target Pressure), please see the relevant FAQ entry HERE.
– To set up a EMHEATER VSD with a Pressure Transmitter to provide Constant Water Pressure using an external Multi-Stage Switch to modify the target pressure (Target Pressure Selector), please see the relevant FAQ entry HERE.
– To set up a EMHEATER VSD with a Pressure Transmitter for Frequency Control using a PID (Manage Water Outflow), please see the relevant FAQ entry HERE.
– To set up a EMHEATER VSD with a Pressure Transmitter for Frequency Control using a PID (Manage Water Inflow), please see the relevant FAQ entry HERE.
– To set up a EMHEATER VSD with AI Input Overrun Limit (using a Pressure Transmitter as STOP), please see the relevant FAQ entry HERE.
For additional Protection Features, please also see:
– To set up a EMHEATER VSD End of Curve Parameters (PID Signal Loss Protection), please see the relevant FAQ entry HERE.
– To set up a EMHEATER VSD Restart (Delayed) after Low Current Protection Condition Occurred (Dry Run Protection Reset), please see the relevant FAQ entry HERE.
