Hey guys, I have almost finished my heat treatment oven thanks to dancom. Anyways I am thinking about building a VFD grinder. I just need confirmation on my understanding of the process. To have vfd control I need a 3 phase motor. The one I am looking at is listed as 1.5hp ac induction, TEFC, 3600rpm, 208-230/460vac From what I understand the vfd takes your standard 220v single phase supply and outputs it into 3 phase? And I can only find vfd's listed for 1 hp or 2hp. Can I get away with 2 hp vfd for a 1.5hp motor? Or is a 1.5 - 2hp motor even necessary or can I go with a 1hp?
I would go with a minimum of 1.5 hp. I have a 1hp and will not go lower than 2hp when I upgrade. There will be no harm in over sizing the VFD and it can actually help if the motor ends up drawing a bit more than rated current. Just be aware not all VFDs will convert single to three phase. You will need to check those specs as some simply pass three phase in and out. When I was an electrician we regularly ran 30hp motors on 60hp VFDs. And it was common to install a VFD rated at double the motors rating. The motor will draw whatever amperage it needs through the VFD, the VFD does not "push" the current at the motor. I will be running my 2hp off a VFD rated at 3hp.
Derick, A 1.5 hp VFD will run a 1.5 hp motor quite handily. Most VFDs will do 110 to 125% for some period of time (typically 1 minute). With my VFD I use two of the 3 phase inputs running it from 240 V single phase power. The output is always 3 phase. Your choice of motor is fine. I have a 2 hp 3490 RPM 208/230-460 WEG and she spins mightily. As Grayzer said make sure the VFD is rated for single phase input. Single phase drives are usually quite small, say 3 hp tops. This is a function of the diodes in the rectifier section of the drive. A 3 phase drive input is expected to share the current through 6 diodes, whereas single phase rated drives are expected to have all the current running through only 4 diodes. So, check the ratings before laying down the cash. In the case of my (Yaskawa) drive it has a 'heavy duty' rating and a 'normal duty' rating of 2 and 3 horsepower. If you have a drive in mind, let me know the model and I can dig up a manual and see for sure if it's going to work for you. Dan
Dan, I was thinking of this: 2 HP 230V 1PH INPUT 230V 3PH OUTPUT TECO VARIABLE FREQUENCY DRIVE and putting it on a 1-2 hp china made ironhorse motor (mainly because the motors are cheap) as kijiji doesnt have any deals on it nearly as good as your score!
Derick, You are looking in the right direction. The TECO (Westinghouse) is a pretty good little drive. Essentially driving a grinder we are looking for a basic Volts/Hertz shaft spinner. When I was researching my drive I came up with a short list. These are all comparable VFDs in a similar price ranges. As you would guess 2hp are cheaper than 3hp. 2HP (1.5kW) Single Phase Schneider - ATV12HU15M2 ATV12 - 1.5kW - 2hp - 200-240V - 1ph input ABB - ACS150-01X-07A5-2 - 2HP, 1.5kW, 200 to 240V, Single phase TECO JNTHBCBA0002AC-U 7300CV AC Drive, 2 HP, 230V 1 PH Input, 230V 3 PH Output, 7.5FLA 3HP (2.2kW) Single Phase Yaskawa - CIMR-JUBA0010BAA - J1000, 200-240V single phase, 2HP/3HP, 10FLA Schneider - ATV12HU22M2 ATV12 - 2.2kW - 3hp - 200-240V - 1ph input TOSHIBA VFS15S-2022PL-W - 2.2kW, 3hp - 240V, 1ph input (same drive as ATV12) TECO JNTHBCBA0003AC-U 7300CV AC Drive, 3 HP, 230V 1 PH Input, 230V 3 PH Output, 10.5FLA There are a dozen of others that deserve to be mentioned, but I have only worked with these brands. I should mention that they are all IP20/NEMA 1 so you'll want to make a way to reduce the dust around them. Moving up to a IP65/NEMA 4 (sealed) drive will cost more. I am moving my VFD into a NEMA 3R enclosure with a fan and and air filter. If the VFD can be mounted away from the grinding that would be better, but it means your speed control is up on the wall somewhere. If you set your drive to accept the analog input for speed (typically 0-10V provided from the drive) you can move your speed control down to the grinder proper. Looking forward to seeing how it comes along. Dan
Work in progress would be appreciated. I hope to build my own within the next year and would love to learn from your mistakes.... I mean witness your triumphs.
