Pm1340gt Lathe Basic Vfd Control Conversion Using The Stock Control Board And Switches

[Genghis6400]

So I am already up to $700 for VFD and enclosure in my shopping cart, and I am probably forgetting some things.

WOW.

@mksj shoot me a DM to discuss the possibility of having this built out. I am growing somewhat overwhelmed. I sent you a spreadsheet of my cart.

Hey Christian I’m in the same boat as you are…. Please let me know what you find out.

 

[Christianstark]

Hey Christian I’m in the same boat as you are…. Please let me know what you find out.

I have ordered a VFD and a braking resistor. Once I order the rest of my parts, I’ll share a list.

 

[davidpbest]

@mksj Time to raise prices? LOL

 

[Genghis6400]

I have ordered a VFD and a braking resistor. Once I order the rest of my parts, I’ll share a list.

Thank you!!! I got both the Hitachi VFD and the Break Resistor already but have Not gotten the Box yet. Getting ready to bring the 220 power line to the designated area of the VFD.

 

[Christianstark]

@mksj Time to raise prices? LOL

I was thinking the same! Everything I locate from Marks list is a good bit more expensive that when he posted that list. I sent him a spreadsheet of pricing from my cart.

 

[Emery]

I am planning on using a Hitachi WJ200-075LF VFD to power the 3 phase 5hp motor in my new PM 1440TL. The input will be 220V one phase. The instructions say to connect the input to L1, L2. Would it be less stressful on the input diodes to connect the input to L1, L2 & L3 tied together?

 

[Jason812]

I am planning on using a Hitachi WJ200-075LF VFD to power the 3 phase 5hp motor in my new PM 1440TL. The input will be 220V one phase. The instructions say to connect the input to L1, L2. Would it be less stressful on the input diodes to connect the input to L1, L2 & L3 tied together?

I think that's why you double the size of the VFD to the motor on single phase and leave one leg open. I'm no expert and didn't stay at a Holiday Inn either so I very well could be wrong.

https://vfds.com/blog/can-a-vfd-convert-single-phase-power-to-three-phase/

Using Standard VFDs for Phase Conversion​

If your motor is too large for VFDs built for phase conversion, it is possible to use a standard VFD for your single-phase power supply. This is done by putting the two hot wires for single phase on the AC input for the VFD and leaving one input terminal open and unused. This does raise a few problems that you have to factor in.


Because you are now concentrating the same amperage on two phases instead of three, failure of your VFD’s input diodes is likely to happen. To resolve this issue, you have to oversize the VFD to account for larger ampacities. A conservative rule of thumb is to double the size of the VFD you need.


For example, if your motor Full Load Amps (FLA) is listed at 15, double that and size a VFD as if you needed to power a 30-amp motor. If you’re confronted with this situation, we recommend you call the one of our experts who can help walk you through this sizing process and find the correct VFD for you.

 

[mksj]

It makes no difference, the limitation is not the diodes but the capacitors and the increase ripple from single phase vs. three phase. On older VFDs they sometimes will connect L2 to L3 if there is phase loss circuitry, but it does not change the increased ripple on the buss. Also on single phase the current spikes are much greater which puts more stress on the components, adding a DC buss chokes decreases this and increase the longevity of components, this also decreases the input fusing/breaker requirements. Newer VFD's measure the input THD and if it exceeds a threshold value it will shut down the VFD. On a 3 phase input VFD's the terminals used for single phase varies by manufacturer. In some cases it makes no difference, in others sub circuits (like the fan) run off of only 2 terminals.

 

[slodat]

@mksj have you looked at Hitachi's new SJ-P1 drives for this setup? I have this newer drive on two CNC machines running the spindle motors with great success, from single phase supply. I have attached the pdf with this info. Of course, the drive should be sized for the output current on single phase. I am very happy with the newer drive. Curious about converting your drive parameters for use with the SJ-P1. I have an Acra 16x40 lathe I just bought, and I'd like to have your awesome control setup on the lathe.

Thanks for your time!

 

[Provincial]

I'm getting started converting a Metal Max (Chinese belt drive) 1340 lathe to 3 phase VFD. The lathe came without a motor, and was discounted heavily because of that. I have acquired a Leeson 2 HP 1740 RPM motor and am using Mike's plans from this thread to fumble my way through this project. I'm using the Hitachi WJ200 drive.

I bought a 240V AC power supply with a 10W, 24V DC output. My plan is to use it for all the 24V DC control power, and am using a 24V to 12V converter to supply power to a digital magnetic tachometer that will display spindle speed.

I have two questions about my 24V and 12V system. First, since I am powering the 24V power supply from a manual disconnect (rotary) switch, can it treat it the same as if I was using the 24V DC power from the VFD? I plan to use terminal 1 on the strip for this, and not connect anything to the VFD. I plan to use terminal 2 for the 24V DC common. Mike's plans use the emergency stop switch to disconnect the 24V control power while leaving AC power connected to the VFD, so my design should work exactly the same. I'll be using the rotary switch to shut the machine off when not in use, and it will power down both the VFD and the 24V system.

My second question is about the 12V system. Do I need to run a wire back to the step-down converter for the negative, or can I use the 24V common system for this? If using the 24V common, I can see where it would be wise to put a diode in the 12V circuit to prevent back-feeding.

As I progress on this project, I'll post some links in this one to any posts I make elsewhere. I'll do this because I feel that others will probably use Mike's excellent plans for conversions of other make machines, and this thread is the focus point. I'll probably post in the Asian Lathes and Mills area, although my machine is very much like certain Jet and Enco models.

Since my lathe has no electrical controls mounted in the headstock, I am using a 6.2x3.5x2.5" plastic junction box that I found on Ebay to mount the switches, speed control, and the tachometer display on the hinged gear cover at the rear end of the spindle. I am mounting a 16x12x8 enclosure on the left side of the headstock stand. This holds the VFD, circuit breaker, rotary switch, 24V supply, 24-12V converter, multi-relay, and a 20-lug terminal strip. This will be very much like installations others have displayed on this forum.

I want to thank mksj for sharing his wonderful plans. This thread enabled me to take on this project, and if it works as well as it should, I plan to do a similar conversion on my Atlas 12x36 that came with a 3 phase 1 HP motor from the factory.