Beginner VFD questions, I want to do it right.

[Cheapo]

I'm thinking of a DURApulse GS20 VFD for my new to me Rockwell radial drill press (15-127) which has a Marathon 1/2 hp 3 phase 230/460v motor.

There are accessories mentioned like line filters, shielded motor wires and a sheet metal piece with cable glands to kind of seal it a little.

It's going to be run in a shop with some dust and potentially a little smoke from cutting fluid.

I don't want to introduce too much noise on the AC lines.

I know I have 110v available in the shop, not sure about 220v.

So first thing, specs:

Is it a bad idea to buy a 1hp VFD for a 1/2hp motor? If I have 220v, how about a 3hp VFD? If it is a bad idea, why?

Can I add a 5 conductor twist-lock connector to move one VFD between multiple 3 phase motors?

Shielded wires? All of my cable runs should be short.

Should I try to do a star ground to avoid loops?

I heard the GS20 has memory for a few motors, has anyone successfully done VFD swapping between tools like that?

Doing it right:

I want a mechanical E-stop button front and center. The NEMA versions have an optional safety interlock switch, is there a good way to do that without spending an extra $3-400 on a NEMA version (that doesn't work on 110v)?

What filters and other stuff should I add to protect the VFD and reduce injecting noise in to the power lines and RF noise through the air?

Is the DIN rail mounting kit substantial enough to mount the VFD on the head of the drill press (with cables hanging) or will it be falling off the rail all the time?

Getting fancy;

I was looking at two drill presses at auction, the one I got and a more typical floor mount press with a drill that has an auto-reversing tapping feature. Can I add some micro-switches to the quill, a stopping resistor and a few buttons or relays to make an auto-reversing tapping feature?

I am really looking for DIY examples of one or all of these things and I want to do it right so I don't spend a lot and then smoke my VFD.

Thanks for the help.

 

[mksj]

To address your questions:
Is it a bad idea to buy a 1hp VFD for a 1/2hp motor? If I have 220v, how about a 3hp VFD? If it is a bad idea, why?
No reason to upsize unless you plan on replacing the motor at some point. Price wise if the difference is small then upsize to the next increment. What you are looking at is the motor FLA and the output rating of the VFD under the rated operating conditions. There is variable torque and constant torque, there is different duty levels typically ND Normal Duty, and HD Heavy Duty. The application determines those setting which also effect the output current rating. There are also other derating such as carrier frequency, temperature, input phase, etc. The maximum VFD size for 120V single phase is 1 Hp, there is one model that has a 1.5 Hp but it has some limitations and you need a 20A breaker to run it. You also need to look at the characteristics of the motor. Short answer to you question, get a 1 Hp 120V single phase VFD.

Can I add a 5 conductor twist-lock connector to move one VFD between multiple 3 phase motors?
Not really, every motor is different, the programming parameters are different, the cost and complexity of switching a VFD between machines is not worth it when you can buy a VFD for $100-200.

Shielded wires? All of my cable runs should be short.
No, not if short. Just keep them away from the motor cable, dont tie them all together or run them in the same conduit. They can craoss but if in parallel keep them at least 3-4" apart.

Should I try to do a star ground to avoid loops?
Yes, star ground and/or ground buss.

I heard the GS20 has memory for a few motors, has anyone successfully done VFD swapping between tools like that?
Only has settings, for 2 motors. I have done installs with that model, I would not swap motors.

Doing it right:

I want a mechanical E-stop button front and center. The NEMA versions have an optional safety interlock switch, is there a good way to do that without spending an extra $3-400 on a NEMA version (that doesn't work on 110v)?
There are different ways of implementing an E-Stop and what it means/you want it to do. The best E-Stop when working on a machine is to unplug it. Some VFD's have what is known as a fast stop and/or E-Stop command, this is designed to stop the machine as fast as possible with the VFD and not tripping an error or having it go into a free run. So with an E-Stop you have a NC which is used for the run command source/sink line and this is also connected to a NO switch block that then connects to the VFD fast stop and/or STO function which deactivates the VFD output. The downside si when the STO is activated, the VFD will not electronically brake. The NEMA version of safety interlocks are not normally used for small scale machines and or the E-Stop is at the machine. This is just a general discussion.

What filters and other stuff should I add to protect the VFD and reduce injecting noise in to the power lines and RF noise through the air?
Generally this is not a problem, and a filter can introduce other issues if you are using a GFCI. Many VFD's will trip a GFCI, in particular single phase. Depending on the leakage current of the filter this could also be a problem, and you need a line filter designed for VFD's not your general Amazon/eBay $20 models. If you have RFI interference then a filter may be needed, shielding of the cable may be needed, and possibly using a toroid on the motor wires.

Is the DIN rail mounting kit substantial enough to mount the VFD on the head of the drill press (with cables hanging) or will it be falling off the rail all the time?
I wouldn't use just the DIN rail, I would hard mount it. DIN rails work well in control cabinets, often when you have a series of VFD's components, why pay the extra money for a VFD DIN rail mounting kit when you can just screw it to a plate. I know people mount them not in an enclosure, but if it is in a dusty enviroment and there is any potential fro contamination with metal chips or dust, not so good of an idea. Minimum is put a flat plate accross the top about 4" above the fan outlet to prevent anything falling in.

Getting fancy;

I was looking at two drill presses at auction, the one I got and a more typical floor mount press with a drill that has an auto-reversing tapping feature. Can I add some micro-switches to the quill, a stopping resistor and a few buttons or relays to make an auto-reversing tapping feature?
It can be done, I have it on my mill. I think most people would recommend a mechanical tapping head. Alternative is to use 3 wire control with a fixed switch for reverse and just flip the switch. I have also wired in F/R jog buttons that people use for tapping separate from the other controls. I use proximity sensors, so mine is all automated, but more complex.

I am really looking for DIY examples of one or all of these things and I want to do it right so I don't spend a lot and then smoke my VFD.
You do not need to overthink it, the programming on that model is fairly easy with a lap top, what you want it to do is very simple. If you want faster stopping you may need to add a small external braking resistor.

 

[matthewsx]

As usual @mksj provides the information needed in a clear, understandable response.

This is why I continue to tag you when people need this info.

Thank you Mark

 

[Cheapo]

Thanks. I'm going to start making a shopping list.

As for the interlock, that evidently cuts out the power at the input so you are sure the VFD is completely shut off for maintenance. I was thinking of that in addition to the mechanical E-stop button that probably triggers STO and the control panel button will trigger a stop with braking probably.

Do you know how to run the control panel on an extension cable? The manual mentioned it but wasn't super specific about how to do it.

If I do all of that, there would be three ways to stop it.

The manual does say that unplugging a running motor is hard on a VFD so I would use the interlock mostly as a master power switch to turn the VFD on or off before I turn the motor on.

I have homework to do.

 

[Cheapo]

I've been doing more reading.

First thing, I want shielded VFD cable to connect the motor but Automation Direct's minimum cut length is a lot more and a lot more expensive than I need. I have a 1/2 hp motor and intend to use a 1hp VFD. The 1hp VFD has an 8AWG cable requirement, the 1/2hp VFD has a 10AWG cable requirement. Since I should not exceed the output that the 1/2hp VFD would produce, is there any problem with using 10AWG VFD cable?

Looking at the manual and the connections for external control, some of the diagrams show what looks like bipolar transistors to me but they don't seem to mention anything about it. Am I totally getting this wrong? I intend to use a 40mm push to stop/twist to reset button. Is NO or NC easier to implement?

With the mounting drawings, it looks like the setbacks should allow me to mount the VFD in a USA style .50 cal/5.56mm ammo can and have enough air space on each side. Will the 1hp VFD running a 1/2hp motor be able to live in a closed ammo can or do I need vents?

If it will work in the can (sealed or not), I intend to remote mount the VFD display, put in nice cable glands for the VFD cable and the display cable and mount an IEC socket so I can have an easy to replace power cable. I will also mount a mains power interlock switch so i can kill power at the box.

I'm thinking i can set the VFD so the knob selects between 0%, 50% and 100% speed on the motor. I'll be able to start and stop with the VFD display buttons or stop it with the 40mm push-to-stop button.

For the tapping, I'm thinking of adjustable constant torque operation to turn things down if taps break. I've been reading about the GS20 ramps and it seems like that should be possible.

Automation Direct seems to sell a ferrite choke for the motor wires and a capacitive filter for the mains, both in the $20 range, are these worth getting? If not, what do you suggest? I don't think there is a GFCI on the power circuit.

I think there is a cable clamp kit for connecting and grounding the cables at the VFD, is that a good idea or is a ground stud on the ammo can sufficient for grounding?

Thanks for the feedback.

 

[rabler]

The 1hp VFD has an 8AWG cable requirement, the 1/2hp VFD has a 10AWG cable requirement. Since I should not exceed the output that the 1/2hp VFD would produce, is there any problem with using 10AWG VFD cable?

That sounds like heavier guage wire than I would expect. Maybe for a 200 ft run VFD to motor. A common approach for a few feet would be to use the motor’s full load amp rating stamped on the dataplate, and use the corresponding NEMA gauge. A 220V, 1 HP, 3 phase motor is not going to draw more than 5 amps per wire, I would expect 14 gauge stranded wire to be more than sufficient.

 

[We-R-138]

Honestly, MKSJ is right. If you have the money and have the time and wherewithal to take it to that level. DO IT!

I am a hobbyist, who has recently begun working with 3 phase powered machinery within the last year. I have currently 2 machines on 240v 1ph VFD input with 240 3ph out. These machines are ran in my shop ( I restore classic cars for a living from my home garage) **daily** (maximum of about three to four hours depending on the task) for the last year.
I am literally using the CHEAPEST VFDs purchased on Amazon, roughly 175$ total for both, matching the hp rating and amp maximum on the mill (3hp) and lathe, 3/4 or 1hp Can’t remember right now. Vfd input Cables plugs into a standard American 50amp 220v receptical that are near 15’ long each. Both are 8 awg or something near that. As for the wire from vfd to machine, I’m using the same cables 8/3 plus a ground. No shielding. As long as you can figure out the darn programming of parameters, since you know, there isn’t much of a manual that comes with them, imho, they’re a totally viable option for someone on a budget. Especially as a beginner.
I tucked the units inside of the cabinets of my lathe and the mill, then either ran a remote fwd and rev switch (on/off/on) a momentary (on/off/on) for jogging feature, and a cheap e stop button on both machines. From vfd to machine the wiring is very simple and honestly, unless you have very sensitive electrical equipment in the shop and very close, it isn’t something to be concerned with.

I’ve even had my 80gallon 6.5hp 1phase compressor, that runs off the same circuit Breaker as both vfd, mind you, turn on during a heavy cut on the mill, and not even hesitate. Same deal with my 205amp AC/DC tig welder running full amps While welding and a buddy fire up the mill and my welding arc or mill werent effected in any way.
Take this with a grain of salt, but the cheapo vfd’s imho, are a viable option. My 9-18 lathe vfd was somewhere in the $50-$60 range. Shipped to my door in less than 48 hours.

This is Just my $0.02.

I’ll post pics if you want of my current set up that’s lasted over a year of daily use without a hiccup. Grinding dust, metal chips, paint fumes (the real deal 2k urethane stuff) Granted, the machines aren’t used heavily alll day every day. Yet I’d say a minimum of one hour on each machine 6-7 days a week. Sometimes used for extended amounts of time though.

I hope this gives you a better idea of what can be done!
-Brian

 

[7milesup]

The 1hp VFD has an 8AWG cable requirement, the 1/2hp VFD has a 10AWG cable requirement. Since I should not exceed the output that the 1/2hp VFD would produce, is there any problem with using 10AWG VFD cable?

As Randal mentioned above, there is absolutely no need to use that large of wire. Size the wire to match the amp draw. I would be surprised if you could get a #10 AWG wire to fit into the terminals of that VFD. I use ferrules on my wires to make things easier.

 

[epanzella]

I had a 2hp BALDOR 3ph motor kicking around from another project. Bought an Amazon 2hp VFD for $100. Just used #12 stranded wire with no shielding. Wiring is a piece of cake with everything labelled. For setup the manual (what little of it there was) was totally useless but the internetz came to the rescue. Been using it for a cupla years now with no issues other than the lack of a power switch. The display is always on unless I snap the breaker. I don't know if they're all like that.

 

[Winegrower]

the cheapo vfd’s imho, are a viable option. My 9-18 lathe vfd was somewhere in the $50-$60 range. Shipped to my door in less than 48 hours.

I agree with this. I bought a G20 for my old Powermatic wood lathe, it works great. I bought a $50 eBay VFD, it drives a 1/3HP motor just like expected. They both have all the features needed. Why pay more?

BTW, I had zero issues with interference, fault tripping, buzzing, etc.