1-wire single phase to fun 40hp pump with vfd
1-wire single phase to fun 40hp pump with vfd
(OP)
We're setting up a pump station/treatment building. The main load will be a 40hp pump with vfd. The other smaller loads in the building are 3 600 watt bulbs for UV and typical lights/receptacles. Can this run off 1-wire single phase?






RE: 1-wire single phase to fun 40hp pump with vfd
RE: 1-wire single phase to fun 40hp pump with vfd
RE: 1-wire single phase to fun 40hp pump with vfd
Good luck
RE: 1-wire single phase to fun 40hp pump with vfd
RE: 1-wire single phase to fun 40hp pump with vfd
Run the numbers - it might be cheaper to throw the motor away and start over with a 3 phase motor.
RE: 1-wire single phase to fun 40hp pump with vfd
That's a great first Subject!
You should see some of the subject screw ups - much worse.
Check with the locals that would supply the VFD. It may well be that the single phase derate is not as draconian as 2X.
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: 1-wire single phase to fun 40hp pump with vfd
But we come full circle back to the issue that boaterbill first brought up, your 200A service is too small for this motor.
As to the breaker to use, the NEC calls for the breaker to be max. 125% of the VFD INPUT current. That 210A VFD has an input current of 231A, so the breaker would be 250A.
RE: 1-wire single phase to fun 40hp pump with vfd
Are there any code rules (NEC, CEC or code where you are) that dictate the minimum size of the breaker (or fuses)? I wouldn't think any code would give a minimum breaker size but I could be wrong. Most codes dictate the minimum wire size and maximum breaker size for safety and protection purposes.
In theory, the Mirus 1Q3 filter should lower the distortion and also allow a 60hp VFD to be used instead of a 75hp. This will save cost on the VFD and lower the total current draw on the power system. Some type of harmonic filter will likely be a necessity to avoid causing voltage distortion on the power system. However, the 1Q3 filter itself is very expensive.
As others have pointed out, you will be running very close to 200A if the motor is running at full load and the service really is too small. But, if the motor is not at full load then it may be ok. The other alternative is to limit the max speed slightly. For example, drop the max VFD frequency from 60hz to 55hz. The current drawn from the line by the VFD is fairly linear to the hp drawn off the motor shaft. So, lower the hp by 10% and you lower the VFD current draw by about 10%.
RE: 1-wire single phase to fun 40hp pump with vfd
I'm trying to learn as much as I can about electricity, but I seem to find things that are either elementary or way beyond my understanding...do you guys know of any good resources that I could check out to get a better handle on it?
Thanks a lot and more ideas are always welcome!
RE: 1-wire single phase to fun 40hp pump with vfd
So winterrules,
If you change to a 30hp pump you will still be able to use that existing VFD (assuming you have someone competent to re-program it) and utilize a smaller CB to feed it. Just make absolutely sure whoever reprograms it knows all of the limitations you have with your installation.