VFD options - experiences with GE af60-lp

[Bob Wise]

I acquired a Davis and Wells 20" bandsaw and decided to put a new motor on it... 3-phase.

Found a really reasonable deal on 1 875 RPM 3phase motor, but only runs 480V - not dual voltage.

I've got two other tools in my shop (Poitras 4800 and Oliver 270D) that I've used the Huanyang VFDs to power.
Cheapo but they have worked for me.

However, the Huanyang units do not support 480V as near as I can find. Also, many of them do not support external braking resistors.

So, I found a reasonably priced used unit off ebay - GE AF60-LP.

On initial hookup and run and seems to work pretty well, but it doesn't seem like many people use them (based on forum surfing).
Anyone out there using these or had a bad experience? Mine has been fine so far.

-Bob

[Bill Adamsen]

Assuming you're planning to use the VFD to produce 3-phase. Does your single-phase service include 480 volts at the load center? Or are you using a step-up transformer first to get the 480volts single-phase? Or does this VFD step up internally? Would love to see more details on the setup.

From reading (well, scanning) the operators and programming manual it looks like a fine VFD.

[Bob Wise]

Assuming you're planning to use the VFD to produce 3-phase. Does your single-phase service include 480 volts at the load center? Or are you using a step-up transformer first to get the 480volts single-phase? Or does this VFD step up internally? Would love to see more details on the setup.

Bear in mind that VFDs will take single phase or three-phase input and give you controlled 3-phase output.
They are not transformers. They will output at most whatever voltage you input.

Bought a Tierney single phase transformer off ebay, 5KV. Stepped up from single phase 240V to 480V. VFD gets 480V from the transformer single phase and outputs 3-phase.
On most units if you are inputting single-phase you have to derate the unit for 3-phase. The recommendations seem to be to derate by 50%.

You COULD transform 3-phase, but the 3-phase transformers are much more expensive.

Works like a charm.

In my case, I bought three really nice 3-phase industrial motors for a total of $125. The low cost of the motors allowed me to spend a few more $ doing the 480V conversion.
In any case, I was actually glad to have an excuse to see if I could get the 480V conversion working reasonably priced - and I did!

So, next time I see some old iron that only supports 480V I won't be scared off. :-)

Transformer cost me $65 to buy, $75 to ship. Didn't have luck locally finding one at this total price, but dry transformers are pretty simple - there isn't much to go wrong with them.
Darn it's heavy, though! Shares the bandsaw base.

I need to post a longer writeup with pictures, for sure.

-Bob

[Bill Adamsen]

Did you put a disconnect between the single phase load center and the transformer? Nice thing about the VFD is that it gives you variable speed and lots of other functionality. Probably not so important for a wood bandsaw, but, for something like a lathe, a big plus.

[Mike Heidrick]

Congrats. I have not graduated to 480v transforming yet. Just got to the 20hp RPC and 3ph panel level in the new shop. Some nice 480v tools out there. How balanced is the output side of the transformer? Can you show its connections?

[Bob Wise]

How balanced is the output side of the transformer? Can you show its connections?

What do you mean about the balance on the output side?

Connections for a single phase 240 -> 480 transformer are pretty simple... three wires in, three wires out (counting ground).
My first time through I put the meter on the output side and had 120. Hah, had wired it backwards.

I shot a quick video of that shows the transformer and VFD, and the motor starting up.

https://www.youtube.com/watch?v=HkITxVgBS1Y&feature=youtu.be

-Bob

[Bob Wise]

Did you put a disconnect between the single phase load center and the transformer? Nice thing about the VFD is that it gives you variable speed and lots of other functionality. Probably not so important for a wood bandsaw, but, for something like a lathe, a big plus.

My setup is:

Wall outlet -> Service Cord -> Transformer -> VFD -> Motor

So, if a twist plug on a service cord counts as a disconnect, yes. :-)

I only have the one tool running 480, so I put the transformer on the base with the saw. It's additional ballast!
The quick video I posted a couple of minutes ago short kinda-sorta show you what I mean.

-Bob

[Bill Adamsen]

Resurrecting this thread because because I am looking to do something similar, but having trouble validating this solution. I have other VFDs running single-phase 230v to 3-phase 230v ... works like a charm. I have a RPC generating 3-phase 230v, and use a transformer to step that up to 440v (multiple taps) ... works like a charm.

When I look at the specs for the VFDs recommended above, I'm having trouble finding a 480volt VFD that takes a single-phase input. Conceptually that would be the ideal situation for several reasons ... cost (single-phase transformer less costly than 3-phase) and then also the output should be more balanced AND would have the VFD functionality like JOG, soft start, etc.

The theory is to take single-phase 240volts from the panel, and step it up to (single-phase) 460/480volt. Then convert to 3-phase with a VFD. This is a proven solution with 230volts. The tool I'm looking at (jointer) is 5 hp so 5kva (5x746) transformer ... worst case 10kva? I downloaded the GE manual for the GE AF60-LP and also the AF300 series and the part number sequence would be as shown on the attached number system diagram. Note the AF300 is 3-phase input only.

I just wonder if I'm beating a proverbial dead horse. Are there single-phase input VFD that produce 460 volt 3-phase output? A search on ebay for "vfd 460volt single-phase" (and variants thereof) and come up with zilch. Hoping I'm wrong.

[Allan Speers]

Bear in mind that VFDs will take single phase or three-phase input and give you controlled 3-phase output.
They are not transformers. They will output at most whatever voltage you input.

Bought a Tierney single phase transformer off ebay, 5KV. Stepped up from single phase 240V to 480V. VFD gets 480V from the transformer single phase and outputs 3-phase.

Bob, I never even thought of that, but one heckuva' good point!

Luckily, the two 460v motors that I've needed VFD's for could be re-wired to 230 240v. Isn't that fairly common, though, with your typical 3-ph woodworking motor?

------------

BTW- I think one thing you wrote could confuse some folks. Quote: "On most units if you are inputting single-phase you have to derate the unit for 3-phase. The recommendations seem to be to derate by 50%." You're talking about using a 3ph -to - 3 ph VFD, but wiring it for 1 ph input, yes? Modern 1ph-to-3ph VFD's don't require such an over-spec, though a little cushion certainly doesn;t hurt.

[Bill Adamsen]

Allan:

Some motors are multi voltage ... and yet many are not. Typically if they are listed 220/440 they are multi voltage. You can usually tell based on the number of leads in the motor. Attached photo is of a 440v only motor on a Yates tool. This is not the motor I'm trying to accommodate. I'm powering this with stepped up 3-phase. But I have considered getting a VFD for some of the control features - speed control specifically. In answer to your question, almost any motor can be rewound to meet specific requirements ... in this part of the USA that is a cost prohibitive practice.

What I'm looking for is VFD setup for a 5hp machine. 3-Phase transformers are more complicated/expensive/heavy than their single-phase counterparts. This is because typically they have three independent transformers in one case ... whereas a single-phase transformer has one. There are other benefits. But at the end of the day, if I can't find a 460volt VFD that takes single-phase input (and none appear to) then the solution doesn't work.

In my searching I also found this little "fine print" in the Teco guide ... ... "***Do Not Apply Single Phase Input Power to these Models" ...

[Bill Adamsen]

I posted a similar thread on Practical Machinist and got some excellent feedback from one of their senior advisors.

http://www.practicalmachinist.com/vb/transformers-phase-converters-and-vfd/460v-vfd-single-phase-input-312064/

Short of it is ... many 460/480v VFD can be run off single-phase, but the list of requirements is long including as Bob pointed out ... at minimum, 50% derating. That would require a 10hp VFD minimum ... in this case it is less costly to find a 5kw 3-phase transformer.

[Bob Wise]

Bob, I never even thought of that, but one heckuva' good point!

Luckily, the two 460v motors that I've needed VFD's for could be re-wired to 230 240v. Isn't that fairly common, though, with your typical 3-ph woodworking motor?

------------

BTW- I think one thing you wrote could confuse some folks. Quote: "On most units if you are inputting single-phase you have to derate the unit for 3-phase. The recommendations seem to be to derate by 50%." You're talking about using a 3ph -to - 3 ph VFD, but wiring it for 1 ph input, yes? Modern 1ph-to-3ph VFD's don't require such an over-spec, though a little cushion certainly doesn;t hurt.

Since the thread is reopened... thought I would comment and report. The cheap-but-good 3phase/440 motor I found was not rewirable. Some are... this one wasn't. You have to check carefully if that matters. In my case the great deal on the motor allowed me to buy the transformer and end up in a happy place. :-) The setup on my bandsaw is working very well.

[Marty Schlosser]

Pardon me for asking here, as I don't want to derail the thread, but I have a 200 Volt 3-phase motor which I've connected via my FM-50 VFD. According to everyone I've checked with I will probably end out burning out the motor because my electrical grid delivers 250 Volts to my shop (home-based, amateur). Is there some way I could bring down the single phase voltage to better accommodate the 200 Volt input the motor expects? I should also mention that the motor plate states it can be run at 208 Volts.

[Bob Wise]

Pardon me for asking here, as I don't want to derail the thread, but I have a 200 Volt 3-phase motor which I've connected via my FM-50 VFD. According to everyone I've checked with I will probably end out burning out the motor because my electrical grid delivers 250 Volts to my shop (home-based, amateur). Is there some way I could bring down the single phase voltage to better accommodate the 200 Volt input the motor expects? I should also mention that the motor plate states it can be run at 208 Volts.

VFD can't manufacture higher voltage than the supply side provides, but it can reduce voltage. You should be fine if you set the VFD to match the motor plate (208V, etc).

Although I don't have data to back this up, I'd guess that (provided you match the VFD output to your motor plate) that your motor should last
longer on a VFD than on utility power... VFD should be cleaning up power spikes, and if you set up for soft start it's easier on the motor and the machinery.

-bw

[M Toupin]

I have a 200 Volt 3-phase motor which I've connected via my FM-50 VFD.

The FM50 is a simple scalular VFD, great if all you want to do is convert from single phase to 3ph and speed control isn't a concern like for a TS, jointer planner etc. The down side is it's the bargain basement of VFDs which means it lacks many of the functions a little better quality drive has such as native 3-wire control and the ability to adjust output voltage.

So in short no you can't adjust the output voltage on the FM50. But to be honest it probably isn't going to matter to a bit. Unless you're running commercial shop were the motor is running for hours at a time every day it's probably not going to make a bit of difference. I've had a 208v motor on a sander running on a FM50 for years and it's still fine. Granted it only runs a couple times a week for a short periods (3min or less usually). But at the end of the day, unless the motor is a specialized motor specifically designed for the machine and is irreplaceable, I'd run it until it died and then replace it with a 220v if it ever does.

Mike

[Bob Wise]

The FM50 is a simple scalular VFD, great if all you want to do is convert from single phase to 3ph and speed control isn't a concern like for a TS, jointer planner etc. The down side is it's the bargain basement of VFDs which means it lacks many of the functions a little better quality drive has such as native 3-wire control and the ability to adjust output voltage.

In short, no you can't adjust the output voltage on the FM50, but to be honest it probably isn't going to matter to a bit. Unless you're running commercial shop were the motor is running for hours at a time every day it's probably not going to make a bit of difference. I've had a 208v motor on a sander running on a FM50 for years and it's still fine. Granted it only runs a couple times a week for a short periods (3min or less usually). But at the end of the day, unless the motor is a specialized motor specifically designed for the machine and is irreplaceable, I'd run it until it died and then replace it with a 220v if it ever does.

Mike

I'm not an electrical engineer so I'm willing to be corrected...

I believe that as VFDs reduce frequency in order to slow the motor down, they also drop the voltage. Voltage reduction/management is an inherent part of the design. The two kinds of VFDs I've used (the cheapo huanyangs and the nicer GEs, voltage configuration for the specific motor is required. I agree that I wouldn't stress about it the motor life even if this were not true, but I'm pretty sure it is.

If this discussion continues I'll have to step into the shop, pull the wire cover off the motor, run it at 1/4 speed and check the voltage. :-)

-bw

PS: Side comment, I'm only using the GEs now. The Huanyangs got me going on this cheap but not buying any more of those

[M Toupin]

Bob, I'm not really getting your point. All VFD's "reduce frequency in order to slow the motor down, they also drop the voltage". No argument there, that's how VFDs work. The voltage is adjusted to a percentage of the hertz output. So for example, at 230v the hz would be 60hz, at 115 volts the hertz would be 30hz etc.

But back to Marty's question - for the FM 50 the base is 230 volts and the drive scales the hertz to the base voltage ie 230volts/60hz, 115v/30hz etc. So if Marty wants to feed his 208v motor he'd have to scale the hertz back to somewhere in the neighborhood of 50ish hertz. No, I haven't done the math and I really don't want to get into a protracted discussion or math lesson, but for a general idea, 50ish hertz is close enough to get the point across. Point is, the base output voltage of the FM50 is set by the input voltage, there's no adjustment. On better quality drives the base voltage is adjustable so you can tune a drive to output a lower voltage say 200 or 208 volts depending on the motor.

But at the end of the day I think we can both agree that Marty will be just fine using his 208v motor.

[Bob Wise]

Bob, I'm not really getting your point. All VFD's "reduce frequency in order to slow the motor down, they also drop the voltage". No argument there, that's how VFDs work. The voltage is adjusted to a percentage of the hertz output. So for example, at 230v the hz would be 60hz, at 115 volts the hertz would be 30hz etc.

But back to Marty's question - for the FM 50 the base is 230 volts and the drive scales the hertz to the base voltage ie 230volts/60hz, 115v/30hz etc. So if Marty wants to feed his 208v motor he'd have to scale the hertz back to somewhere in the neighborhood of 50ish hertz. No, I haven't done the math and I really don't want to get into a protracted discussion or math lesson, but for a general idea, 50ish hertz is close enough to get the point across. Point is, the base output voltage of the FM50 is set by the input voltage, there's no adjustment. On better quality drives the base voltage is adjustable so you can tune a drive to output a lower voltage say 200 or 208 volts depending on the motor.

But at the end of the day I think we can both agree that Marty will be just fine using his 208v motor.

Agree that he should be just fine.

If that's a limitation on the FM50, totally understand your point. I'm a bit surprised by that I thought that even the really cheapo huangyan units had adjustable (downward from the input) output voltage.

[Marty Schlosser]

Thanks for your thoughts on this issue, guys.


Agree that he should be just fine.

If that's a limitation on the FM50, totally understand your point. I'm a bit surprised by that I thought that even the really cheapo huangyan units had adjustable (downward from the input) output voltage.

[Rollie Meyers]

It is a code violation to use a 208V (new rated voltage 200V) on 240 volts, a older 220V rated motor will do fine on either 208V or 240V, but a 230V rated motor cannot be used on 208V, or 200/208V motors on 240V, if a VFD that can have the output voltage adjusted lower then the input that is the easy way to do it, otherwise a buck/boost transformer to buck the voltage down to 208V is another option, in the case of a couple of Rockwell former school machines I bought that had 200V single voltage motors, the VFD's that were used on them allowed them to be adjusted to 208V output. Note: a VFD cannot output 240V from a 208V supply.