Hello, I am experiencing difficulties in pairing a 50HP submersible pump with a PF755 VFD (480V 3-Phase, 65(ND)/52(HD)). The issue arises during the static AutoTune phase when trying to use new drives with an existing pump. A 'Code 77, IR Volts Range' fault is being detected. The distance between the pump and the drive is approximately 50 meters or possibly longer. The submersible pump is being lowered into a hot-water drilled hole (through Ice) to a depth of 50-100 meters. It is used to recover spent water from drilling operations and returns about 90% of the output to a surface rodwell for the drilling process. The PF755 VFD is operated at the surface and is not submerged. The feedback for the PF755 is open-loop using Induction FV motor control (P35). We are currently attempting to tune the newly installed VFD with the pump motor using the static method. The pump and motor are not submerged at this time. We are seeking suggestions and troubleshooting tips to successfully match the VFD with the pump. The F77 error is occurring with multiple PF755 and both the primary and spare pump. Thank you for any assistance. -- pawPLC. -- The motor's nameplate information is provided, with details such as Voltage: 460 VAC, Amps: 67.70, Hertz: 60 Hz, RPM: 3450, Power: 50 HP, Poles: 2.
After analyzing the motor voltage and rated current at the time of the fault, it appears that the motor resistance may be lower than expected, around 0.064 Ohms. While this value could be appropriate for a 50HP motor, it still seems somewhat low. Have you considered the use of encoderless induction flux vector control for this particular application? Are you anticipating the need for torque control in the future? If not essential for a specialized pump application, I would suggest utilizing volts/hertz control instead. Simply input the motor nameplate information and you should be good to go. However, if the autotune process failed as it did, it could indicate underlying issues. It would be wise to gather more detailed motor data and verify the accuracy of the motor resistance.
Hi Keith, thank you for your prompt response. While our pumping application may not be specialized, we have found that utilizing Field Voltage Control (FVC) provides us with more precise control and stability compared to other methods. Currently, we are facing a unique situation where both our primary and spare pumps are exhibiting the same response to an autotune feature from separate PF755 drives. Despite this, we are still unsatisfied with the results as the autotune process fails to meet our expectations. In our next troubleshooting steps, we are considering trying the Induction SV option and if that proves unsuccessful, we may explore the VHZ mode as a final resort. Unfortunately, as we are located in a remote base camp, we do not have access to another cable to test at this time. Thank you for your assistance, pawPLC
Greetings and a warm welcome to the online community! It is important to adhere to forum guidelines by refraining from posting copyrighted materials. A helpful practice is to provide a URL link to the relevant knowledge base article in your posts.
Welcome to the forum! In order to comply with forum policies, it is important to avoid posting copyrighted material as attachments. A useful alternative is to provide a URL link to the KB article in your post. However, please note that the editing window for posts is limited, so it may be too late to make changes once you have posted.
Thank you to Mikey and others for bringing this to my attention. I kindly request that the board administrators remove the articles as soon as possible. My apologies for any protocol breach. --pawPLC.
Hey there pawPLC, it seems like quite a wired puzzle you're dealing with. From your detailed post, it sounds like the issue may be due to a voltage mismatch. An IR Voltage Range fault usually suggests that your incoming voltage is either too high or low to correctly perform auto-tune. Considering the distance between the pump and the VFD is quite long, there might be a voltage drop over the distance. Also, ensure your grounding is adequate and properly connected, as it might lead to high impedance path affecting the voltage measurements. You might consider moving the VFD closer to the pump or using appropriate cable lengths and gauges to reduce any potential voltage drop. Good luck and do keep us updated!
✅ Work Order Management
✅ Asset Tracking
✅ Preventive Maintenance
✅ Inspection Report
We have received your information. We will share Schedule Demo details on your Mail Id.
Answer: The fault indicates an issue related to the IR voltage range and can occur during the static AutoTune phase when pairing new drives with an existing pump.
Answer: The PF755 VFD is operated at the surface and is not submerged, while the submersible pump is lowered into a hot-water drilled hole at a depth of 50-100 meters.
Answer: The feedback for the PF755 VFD is open-loop using Induction FV motor control (P35).
Answer: Troubleshooting tips may include checking the distance between the pump and the drive, ensuring proper motor specifications are met, and verifying the setup parameters for successful matching of the VFD with the pump.
Join hundreds of satisfied customers who have transformed their maintenance processes.
Sign up today and start optimizing your workflow.