Lewis_RX8
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Will the existing motor run on 240V 3-phase? Most VFDs can only output the same maximum Voltage as they are supplied with. There's usually a sizeable premium for those with the ability to step up the Voltage.
Most recent 3-phase motors below about 3HP, 2.2 kW, are wound for 230V in Delta and 400V in Star. From about 3 kW up, they are usually 400V in Delta and 690V (ish) in Star to allow Star-Delta starting, which is/was the old-school way to reduce starting current. At 7.5 HP, this probably applies to your motor, so check the motor plate.
If you do go with a VFD, I'd certainly expect a speed control pot to be useful. When I was playing with VFDs on my lathe (an old and knackered 9" SouthBend), being able to vary the speed during facing cuts eliminated the transition from nice finish to lousy finish at some arbitrary diameter.
I see , I've not got my hands on the lathe at the moment it's currently on a pallet on its way however just thinking ahead but will be checking the motor plate and as you say maybe the speed could be handy for that type of stuff instead of being stuck to all that the gears offer
Unfortunatley no one makes 3 phase 380-440v inverters in the same price range as the VFD's despite being simpler.
To keep the lathe as its intended you'll want a 3ph 440v inverter or transwave rather than a VFD.
I like the VFD option, much simpler not having machine tangled in wiring.. All my controls are on the vfd enclosure and foot switch - nothing on the machine. My lathe is simpler, I dont have or need any interlocks but its only me using it.
The Vevor brand/seller is also on Amazon and like the rest I think its a china based seller with UK based stock.
Anything like this I'd prefer the ease of amazon prime's returns rather than ebays guarantee.
Theres nothing on Amazon, since ITV reported on them disposing items..
This is a few quid more but has the advantage of prime next day and very easy returns.
Variable Frequency Drive, 220VAC Input 3-Phase 30VAC Output 7.5KW, High Performance Drive Single Phase Variable Frequency Drive Converter Speed Controller Converter : Amazon.co.uk: Business, Industry & Science
Shop Variable Frequency Drive, 220VAC Input 3-Phase 30VAC Output 7.5KW, High Performance Drive Single Phase Variable Frequency Drive Converter Speed Controller Converter. Free delivery on eligible orders of £20 or more.www.amazon.co.uk
A few months back a lot of them were <£30 each. I didnt buy any but I know a few members did
I see , looks like Ronan has it powered Via VFD so that route may work well actually and easier cheaper than transwave or inverter
Fantastic stuff , my lathe has the two speed motor which may complicate things slightly but seems a good chance it'll work and I would't need the two speeds could just use the VFD for that anyway, is that a 3 phase 240 volt VFD running yours or is it the 440 volt one. If you not mind getting a pic of it whenever that would be great aswell.I have a vfd on my lathe which is the same as yours. I used the original start stop buttons on the front as inputs to the vfd to start and stop the motor. The only other thing is the suds pump, which i wired up to single phase by putting a capacitor across two of the legs of the pump motor, works fine off a three pin plug.
Looks neat and I'll definitely have a read of the thread to get some ideas to steal for mine , is that a RPM readout taken from the headstock or just calculated with gearingAs mentioned above. I did a thread recently on my student. I managed to re purpose all controls to function my lathe in the same way it would normally. The switches just become signal switches rather than being power switches.
I also added some extras with a potentiometer and a jog function etc. all inexpensive. Just a little bit time consuming if you attempt to make it look factory like I did.
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Thanks everyone for the inputs , think I'll wait till the lathe arrives just to check the motor then I'll probably be going down the VFD route as hoped. Knew this forum would have some knowledge and experience with this type of stuff