Invertek VFDs

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Ceej0103

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Hello,

I'm rebuilding a Jet 1340 lathe and wanted to replace the single phase 3hp motor with a three phase motor and VFD control. Primarily because the circuitry in the lathe's cabinet was toast and I didn't know how to fix it. At the time, contactors, overloads, relays, and all that jazz had me confused. I'm now more confident in that regard, but I still like the VFD and 3-phase over single phase/single speed. Probably a little overkill, but I purchased a 5 1/2 HP Marathon motor with a 112M frame (same frame as what came off my Taiwan-made JET 1340), inverter rated for continuous duty. Since I invested in a nice motor, I decided to invest in a nice VFD as well.

I purchased the Invertek Optidrive E3. I had very little experience with VFDs and no experience using low voltage control circuits. Everything I had done was on the VFD's control panel. The manual was still a little overwhelming, but I was able to get the motor up and running. From there, I was a little out of my league.

Here's the reason I'm writing this post. 888-862-5659. That's the technical support for Invertek. I have no way of expressing how F*#$ING amazing these guys are. Specifically a guy named Matt. There was no ticking meter and the feeling of being rushed. He wanted to know the intimate details of my application to make the drive work for me how I wanted it to work. He was as much an educator as he was a technical resource. Making sure I understood the concepts of advanced motor control using their VFD so I could apply those concepts to the information contained in the charts within their manual. Basically he taught me to fish instead of giving me a fish. I went from knowing virtually nothing about the capability of a VFD (beyond changing single phase to 3 phase) to doing some rather advanced wiring on my lathe. This includes:
  • Integrating all the existing safety limit switches and applying a fast-stop command if they're tripped during operation (opening panels that shouldn't be opened during operation). This includes lock-out until the condition is rectified (ie. cant start the lathe if I opened the change gear door until I close it). Chuck goes from 1800 RPM to 0 in less than a second.
  • Integrating limit switches for apron forward/reverse control, subject to lockouts. Won't work if any Normally Closed safety limit switch is opened.
  • Integrating limit switch for brake control with DC Injection Braking. No more brake pad running on a motor pulley journal. I put a little pressure on the brake pedal, a lobe on the shaft closes a limit switch, and the chuck stops in about 3 seconds. I put the pedal to the metal and the shaft's second cam engages a second limit switch and initiates a fast-stop, which brings the chuck to a dead stop in less than a second. I haven't done enough research on the effects on the headstock gearing when I bring the lathe from full speed to dead stop that quickly. Until I do my research on the wear/tear of that action, I'll only use fast-stop when it's necessary. If I find that there's virtually no impact on the health of the gears using fast-stop, I'll probably just switch to always fast-stopping.
  • Low voltage switches have replaced the old high-voltage switches that were crusty and decaying.
    • I have 2x 30mm illuminated push button latching switches that now control: flood coolant on/off, lathe lights (2 overhead, 1 snake light) on/off.
    • 1x 22mm keyed switch. This runs to a contactor that interrupts the 3 legs of power between the VFD and the motor. When key is inserted and turned to on, contactor coil is engaged and power can pass from VFD to Motor. When not in use, key is removed and tucked away where curious kids can't find it.
    • 1x 22mm 10k Potentiometer to control lathe speed. I will be installing a tachometer soon.
    • I have 1 original hole remaining with a 30mm illuminated latching push button....not sure what I'll use it for....maybe to turn on my TV?

So, this post has gotten really long, but I felt folks may have a greater appreciation for the support I received when going from VFD-dumb to where I am now using Invertek's free support. The long and short of it is, if you're in the market for a drive and don't mind paying a little more than the generic Chinesium drives on Amazon, and this is your first rodeo, you might be wise to get an Invertek and call Matt for some help.
 
It’s interesting to me how impeccable the timing is of your post. I just bought a 3hp three phase lathe that I’m trying to figure out how to power up, VFD or rpc or motor swap. I suspect a VFD would be the cheapest way to go but I don’t know my way around those things. Your post about Invertek seems like a good possibility for me. Thank you.
 
@Ceej0103 @BEI would be helped if you described your steps and how long it took to change over everything.
 
BEI said:
It’s interesting to me how impeccable the timing is of your post. I just bought a 3hp three phase lathe that I’m trying to figure out how to power up, VFD or rpc or motor swap. I suspect a VFD would be the cheapest way to go but I don’t know my way around those things. Your post about Invertek seems like a good possibility for me. Thank you.
Click to expand...

VFD for sure. You have to also evaluate the the value of the features you gain with a VFD over a single phase solution. The only knock I have heard about Invertek's is they don't have a ton of analog/digital inputs, but they do sell modules for expansion. Think of an analog/digital input as a terminal that allows you to make the VFD do something. Turning on the lathe in FWD takes 1 input. Turning on the lathe in REV takes another input. If you want to use a potentiometer for speed control, another input.

That said, the Invertek somewhat solves this by programming certain actions when triggering two inputs at the same time. For example, Input 1 On FWD; Input 2 On REV. Input 1 + 2 simultaneously, FAST STOP. The way this is achieved is input 1 is a normally open (NO) limit switch (LS). Input 2 is the same. A lever on the apron moving one way triggers one of those NO LS. Moving the other triggers the other. The lever itself is unable to close both switch simultaneously. This is due to the lathe having cam lobes on the power shaft that trip either one or the other. Now the brake pedal, that has a third NO LS and it’s own cam. By running 1 wire to the terminal that controls ON FWD and another to the terminal that controls ON REV and then hooking those up to the limit switch on the brake, I’m able to connect a circuit between those two terminal simultaneously, resulting in the lathe stopping quickly.

Now that I've done it, and recently, it would be no problem at all to get your started. Not sure how comfortable you are working in your load center, but I can take you all the way from the breaker to the VFD and down to the components, if you want.
 
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Pics or it didn‘t happen;)

Sounds like a great setup….

John
 
matthewsx said:
Pics or it didn‘t happen;)

Sounds like a great setup….

John
Click to expand...

Here’s a teaser. I would have done a complete talking video, but my shop is so messy from focusing on the lathe build that I’m literally embarrassed. I’m going to focus on getting my space back in order, then a more detailed video to follow. This is just me firing up the spindle from the apron controls and then ramping down the speed with the pot. I then show you how I’ve replaced the old high voltage switches with 3 low voltage latching backlit push buttons, a key switch that controls main power to the VFD to lock down the machine and the 10K POT. One button goes to work lights, one to coolant pump, one to siren in the house if I need my wife to bring me a sandwich and some chips.


 
Nice work, need to go the extra step with my lathe….

john
 
Your post was perfect for me as well; I just got a Precision Matthews 1236, and went with a 3-phase motor and VFD, an Invertek E3 the same as you. Taking the support number from your post, I called and spoke with a tech named Jared, and he very quickly understood what I was wanting to do and answered all my questions. I agree, they have fantastic tech support, it was *WELL* worth the higher price vs a Chinesium model!
Ceej0103 said:
That said, the Invertek somewhat solves this by programming certain actions when triggering two inputs at the same time. For example, Input 1 On FWD; Input 2 On REV. Input 1 + 2 simultaneously, FAST STOP. The way this is achieved is input 1 is a normally open (NO) limit switch (LS). Input 2 is the same. A lever on the apron moving one way triggers one of those NO LS. Moving the other triggers the other. The lever itself is unable to close both switch simultaneously. This is due to the lathe having cam lobes on the power shaft that trip either one or the other. Now the brake pedal, that has a third NO LS and it’s own cam. By running 1 wire to the terminal that controls ON FWD and another to the terminal that controls ON REV and then hooking those up to the limit switch on the brake, I’m able to connect a circuit between those two terminal simultaneously, resulting in the lathe stopping quickly.
Click to expand...
I’m setting up my drive the same as yours, where Fwd + Rev at the same time will do a fast stop, but I’m a bit confused by your description: wouldn’t tying the brake switch to both fwd/rev inputs mean that any time one normal switch closed, the other inout would see the closure also? I’d think that you would need a couple of diodes to prevent that from happening. (Or maybe your brake switch is DPST?)
 
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