VFD questions for a Bridgeport

RYAN S said:
Thanks for all of the advice! I will definitely use the 220 volt for the input. I am looking at the Teco L510 and the Hitachi WJ200. Any reason to go with one over the other? Also where would you buy one from. I was looking on wolf automations web site has anyone used them?

Thanks!
Ryan
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I have Teco, Hitachi WJ200, Allen Bradley and generic VFD's. The Hitachi WJ200 has the most programmable functionality. As far as which VFD runs their respective motor the best... I can tell absolutely no difference between them. Back in the day the VFD control circuitry was custom and proprietary. Now days all the control functionality has been implemented on single chips and from what I see all the less expensive VFD's use these same chips. For me if the machine operation is simple I just go with the generic VFD's and save the money.

Example of a VFD specific micro-controller... notice the price - $4.66, this is why the price of VFD's have come down so much that they are affordable.. and the price drop in power transistors... IGBT's and MOSFET's. The WJ200 undoubtedly uses a proprietary control chip but I would bet the cheaper Hitachi VFD's use the off the shelf control chips, I think they have to to be competitive.

https://www.onsemi.com/PowerSolutions/product.do?id=LC87F6AC8A
 
Jester966 said:
My lathe has a 3hp 575V 3-phase motor. I run it from 220v single phase using this VFD:

https://www.aliexpress.com/item/890...29&spm=2114.12010612.8148356.1.608d74eb3uVBB6

I only have about 2hp now with this arrangement, but it's still plenty for what I do. Forward/Reverse/Off lever on the lathe is wired to the control terminals on the VFD and everything works perfectly.
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Cool! I have not seen a step up VFD in anything other than 120v to 240v before... it is nice to know they exist!
 
chips&more said:
Does this mean you only have 380V for a 575V motor?
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In theory, according to their specs, yes. But to be honest I'm not 100% sure. The voltage measured over each phase with my True RMS Fluke meter is actually closer to 480v. I'm not an electrician and I don't understand it exactly, but I think the difference may have to do with the non-sinusoidal AC wave form produced by the VFD.

Either way, at 60hz the motor still runs at 100% of its rated speed, but produces less than the rated power due to the lower voltage. I'm not sure if there's a way to measure the actual power, but it is significantly more than my previous lathe which had a 120v 1hp motor. I also have more than enough power when slowing down to 30 or even 20hz, though my personal preference is to use the headstock gears to change speeds and typically just use the variable speed for fine tuning.

I should also mention that the HY "step-up" VFDs do NOT have the ability to add a breaking resistor. It's not an issue for a mill, but may not be ideal for all lathes. My lathe has an electro-mechanical brake though, so for me it's a non-issue. I did test it with the brake disconnected though; if I remember correctly, I was able to reduce the deceleration time to 3 seconds, but anything less caused an error.
 
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