Need recommendation for VFD for older (1960s) mill

[MikeInOr]

Any thoughts on something like this one? Seems a lot less expensive.

VEVOR 3 Phase Converter - 5HP 15A 220V Single Phase to 3 Phase Converter, Digital Phase Shifter for Residential and Light Commercial Use, 220V-240V Input/Output (One Converter for One Motor Only) | VEVOR US

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That is simply a static phase converter with a solid state relay instead of a mechanical relay making it "Digital". ANY phase converter device that is rated for a range of hp is a static phase converter.



The starting capacitor in the static phase converter is sized for a range of motor horse powers. All of these devices will only be powering 2 of the 3 legs and will derate the motor HP to 2/3rds of the motors rating. Static phase converters have been around for many decades and the do work. I personally don't like them.

A 10hp VFD on the other hand will properly power a 1hp 3phase motor by simply entering the proper motor parameters into the VFD. A VFD powers all 3 legs of a 3 phase motor equally.

 

[MikeInOr]

Thanks @MikeInOr and @mksj for your comments. @mksj, thanks especially for digging up the relevant detail regarding the 2 speed motor in the FP1. I had neglected to mention that.

While I am a novice with VFD installs, I am quite comfortable around electronics. This will be the only 3 phase device in my workshop (others already have dedicated VFDs) so I am leaning away from getting a phase converter.

A quick search on this forum and elsewhere tells me that I need to disable the built in speed control on the FP1 to use the VFD since it likely uses separate windings for each speed. Alternatively I believe I need to shut down the VFD each time between making speed changes. Maybe the VFD settings for each set of windings is different so it may be best to disable the speed change.
Yes, there is a switch downstream of the VFD which is apparently a no-no but I can disable use of the switch while in operation since I am the only one using it.

@MikeInOr, I really like the features on the WJ200 and it appears to do everything I want. I will also explore the Huanyang.

My Enco mill has a 2 speed motor. It is GREAT when running on a RPC or 3 phase circuit because I can cover my most used RPM ranges without having to swap the belt all the time.

When I added a VFD to my Enco 2 speed mill I ignored the low speed and permanently wired it to only use the high speed wiring configuration of the motor. It runs fine at 20hz which is slower than the low speed setting of the 2 speed motor at 60HZ. It also happily chugs along at 100hz.

I built my RPC with a 10hp idler about 35 years ago. It is great because I can bring a new acquisition home and immediately plug it in and run the machine. Slowly over time all my 3 phase machines have been converted over to VFD's because it is simply easier to be able to plug a machine into any single phase 220v outlet in the shop. Even machines that do not need variable speeds (table saws) have been converted to VFD's for convenience.

P.S. I have had a hell of a time enabling the Braking resistor on the WJ200 that powers my lathe. There are a dozen parameters in the WJ200 VFD that have to be set properly for the braking resistor to be enabled properly. On my Huanyang VFD's there are 1/10th the number of settable parameters and it only took 3 parameters to enable the braking resistor. I wish I had purchased a Huanyang for my SB13 lathe!

 

[matthewsx]

@mksj is the resident expert on VFD installs here and he’s said everything I was thinking and a whole lot more.

Most of us who know what machine you’re talking about would give our left …to have one in our home shops.

Don’t mess with it.

Get the phase perfect and get to work.

John
(who was wiring 3 phase machines at work today).

 

[6061T6]

I feel very fortunate to have found this machine . It belongs to someone who is local and has maintained and used it for many years. He is mainly doing CNC with multiple 5 axis machines that he uses more nowadays (Haas TL5, Maho DMG etc.)
He doesn't bother with VFDs etc as his shop is wired for 3 phase.

 

[matthewsx]

I still have my little Hardinge and here’s why it’ll never get a VFD.

Post in thread 'Hardinge BB4'
https://www.hobby-machinist.com/threads/hardinge-bb4.95540/post-893789

VFD’s are great for lathes that have few controls, or new ones that are owned by folks who want the ultimate setup like @mksj does.

Milling machines not as much. If the electrical are intact it’s much better IMHO to run off a static or rotary converter and use the stock controls.

John

 

[6061T6]

I spoke to Phase perfect today to enquire about purchasing their simple converter (5hp) They were not comfortable recommending this version because it has a 2 speed motor and regenerative load that it may produce. They directed me to their PTE007 which costs $2500.

At this point, it no longer makes economic sense to go down this route. I am also not convinced of their reasoning. Doesn't every motor produce regenerative load? What does a 2 speed motor have anything to do with it? If indeed the PTS005 will be satisfactory, I didn't like that they wont stand behind that product and want to unnecessarily up sell me.

If I went the VFD route and the motor did indeed get destroyed by VFD spikes, rewinding a motor like this would be expensive -- around $1000. New bearings might be $100. Still much cheaper than a phase perfect.

I am now leaning towards the VFD route and taking all possible precautions - like getting a high quality unit, using a shaft grounding ring, sinewave filter and ferrite coils to reduce high frequency harmonics. I suspect it will all be ok.

 

[matthewsx]

I run my mill off a static phase converter.

Static Phase Converters | Electronic Phase Converters | NAPCco

Static Phase Converters A static phase converter is used to generate 3 phase power during the starting of a motor. A static phase converter consists of one or more start capacitors and a start relay. The start capacitors produce electricity across the third winding of a motor during start up,

www.northamericaphaseconverters.com

I understand the Phase Perfect is considered one of the best but you should be able to get your mill going with one from North American for $200.

They can be converted to a rotary with the addition of any appropriately sized used three phase motor you can find.

Reasons for not going with a VFD have less to do with potential damage to the motor than the challenge of rewiring everything to make it work with original controls.

John

 

[6061T6]

I run my mill off a static phase converter.

Static Phase Converters | Electronic Phase Converters | NAPCco

Static Phase Converters A static phase converter is used to generate 3 phase power during the starting of a motor. A static phase converter consists of one or more start capacitors and a start relay. The start capacitors produce electricity across the third winding of a motor during start up,

www.northamericaphaseconverters.com

I understand the Phase Perfect is considered one of the best but you should be able to get your mill going with one from North American for $200.

They can be converted to a rotary with the addition of any appropriately sized used three phase motor you can find.

Reasons for not going with a VFD have less to do with potential damage to the motor than the challenge of rewiring everything to make it work with original controls.

John

Unfortunately, they explicitly say that static phase converters won’t work with 2 speed motors.

 

[matthewsx]

Rotary converter?

John

 

[mksj]

That is quite surprising that you have a 2 Hp motor and Phase Perfect is saying you need a 7 Hp unit to drive it. Makes no sense, and I do not see that the regenerative load would be an issue. Very disappointed. You could start out with an RPC, as mentioned you can buy a control box and source the idler motor locally and save $$$. A VFD is unlikely to cause an issue with the motor, typically the issue with insulation breakdown and bearing damage is at the higher voltages and with long motor cables. I would not worry about it, might just use a DC choke, there are VFD output filters but probably not worth it. If the motor is a belt drive and nothing unique as to the mounting, it could also be replaced with a single speed 3 Hp motor, and that would be less expensive then adding filters, etc. There would be plenty power to use it as variable speed without a cooling fan.

Depending on the wiring, one could setup the VFD for both motor winding configurations, when selecting for the alternate speed the current mechanical switch one could add another switch that would change the VFD motor operating parameters. I still would recommend a 3 Hp VFD, as I have had issues with 2 speed motors and VFD's. I prefer the Yaskawa drives, I have used them for most of my recent installs. Either one below if using your current motor, the Yaskawa GA50UB012ABA if you where to use a 3 Hp motor. I can help you with the parameters, you can add an external braking resistor for quicker stopping, but no reverse. You would use 3 wire control which is basically a momentary start/stop button. That part is pretty basic, I would limit the variable speed to maybe 40-80 Hz and no higher than 8kHz carrier frequency.

DURApulse GS20 series AC general purpose drive, enclosed, 230 VAC, with 1-phase input

https://www.automationdirect.com/adc/shopping/catalog/drives_-a-_soft_starters/ac_variable_frequency_drives_(vfd)/general_purpose_vfds/gs21-23p0

https://www.automationdirect.com/adc/shopping/catalog/drives_-a-_soft_starters/ac_variable_frequency_drives_(vfd)/general_purpose_vfds/gs23-27p5

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