Hello everyone, I am working on creating a wiring diagram for two VFDs that will be controlled by a single pressure switch contact. I would greatly appreciate any advice on how to set up the wiring without the need for extra splitters. I have included the VFD wiring diagram and the current proposed wiring for reference. Thank you for your help.
One strategy to enable the second VFD without using the 24v from the first is to wire a run contact from the first drive to the input run of the second drive. By disconnecting the 24v link from the second drive's run relay and instead feeding it from the first drive, the second drive's run output becomes volt free. This setup allows the first drive to activate the second drive when the pressure switch is engaged, creating a seamless operation between the two drives.
To combine the DC Commons of each drive and utilize a single voltage source, they must be connected together. It is crucial not to link the +24V lines. Ideally, an external 24V supply should be used, with its DC Common connected to both drives. However, connecting the DC Commons of the drives and the DC Common of the switch (either Pin 3 or L-) should also suffice.
Thank you very much for your valuable input. I would like to enhance the understanding of the pressure sensor input by connecting one contact to the VFD(s) and one analog signal to the PLC. For further information on the pressure sensor signals, please refer to the image attached.
If the system is dependent on both drives being powered, following @drforsythe's advice should resolve the issue. However, if you anticipate the need to operate with one pump offline (due to maintenance, malfunction, etc.), you may encounter issues with the sensor losing power. In such cases, it is recommended to utilize an external 24V power supply with the 0V terminal connected to the COM terminals of both drives. While you mentioned reluctance towards using a splitter, an alternative solution could involve incorporating a 2-pole relay. By connecting the relay's coil to the sensor and its contacts to each drive, you can maintain isolation between the drives' 24V supplies, which may be beneficial in your specific scenario. Considering that you already have a PLC in place, another viable option is to connect the sensor's digital output to a PLC input and utilize 2 PLC outputs to manage the drives. This approach offers additional flexibility for future modifications. While you may not require this setup immediately, it's worth noting that circumstances can change rapidly.
Benefits of using an auxiliary relay in a circuit.
Hi there! From what I can gather, you could essentially wire your pressure switch in parallel with both VFDs' control inputs, given that it can handle the merged load. Thoroughly inspect your schematics to ensure they match with real-world components, and don't forget to pay attention to the voltage ratings and always adhere to safe practices. For more accurate advice, could you possibly provide more information about the specific VFDs and pressure switch you're using? Also, it would be beneficial to understand what safety features are integrated in your system. Stay safe and happy wiring!
Hi there, It's great that you're taking the initiative to design this yourself! A simple solution could be to use a parallel circuit, which could allow the single pressure switch to control both VFDs simultaneously. If the pressure switch is a simple contact type (open/close), you can wire the two VFDs in parallel directly from the switch. Just ensure that your electrical rating for the switch can handle the combined input of both VFDs. However, this is just a suggestion on the top of my head and you might want to consult with an electrical engineer for a more detailed, safer procedure.
Hi there, If I understand correctly, you're trying to avoid extra splitters but you want to control both VFDs by a single pressure switch. One possible solution would be to wire the pressure switch into the "enable" input on first VFD, then use the auxiliary contact output (normally open or closed) of the first VFD to signal the "enable" input of the second VFD. This would maintain your control scheme without any need for additional splitters. Hope this helps!
✅ 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: Answer: One way to achieve this is by connecting the common terminal of the pressure switch to the control terminals of both VFDs, ensuring that the wiring is done in parallel. This setup allows the pressure switch to control both VFDs simultaneously.
Answer: Answer: It is important to ensure that the wiring is properly insulated and secured to prevent any short circuits or loose connections. Additionally, double-check the wiring diagram to confirm that all connections are properly aligned with the specifications of the VFDs and the pressure switch.
Answer: Answer: To wire two VFDs with one pressure switch contact, start by identifying the common terminal on the pressure switch and connect it to the control terminals of both VFDs. Make sure the connections are secure and follow the wiring diagram provided by the manufacturer for accurate setup.
Answer: Answer: Prioritize safety by ensuring that the power source is turned off before working on the wiring
Join hundreds of satisfied customers who have transformed their maintenance processes.
Sign up today and start optimizing your workflow.