[sohcpwr]

Im looking to get some feedback on a system I built for my milling machine, but would work for any mill, lathe, or 3ph machine for that matter. Everyone who has run a step pulley mill is probably guilty of running the tool slightly out of its speed range rather than going through the trouble moving the belt on the motor. I bought my first mill a couple months ago because it was in fantastic shape out of a guys home shop. Instead of using the rotary converter I had already, I decided to buy a VFD and when I read the manual and saw how many options you could have with the thing, I got a little crazy. After I was done I looked for similar products and the only one I could find was the servo brand panel. That unit is over $1500 and it didnt seem to make use of all the VFDs options. So I am thinking about starting up a website if there is enough interest in the product.


Attachment 317030
This panel has the normal 3 position switch, JOG fwd and rev momentary buttons- the speed on these can be preset to whatever you'd like independent of the run switch. I have it set at 80rpm for tapping. E-stop to far right, speed control potentiometer on bottom left, digital display of spindle RPM, and coolant switch connected to VFD relay output. This is for the spray mist setup I havent hooked up yet. When in operation, the coolant will come on only when the switch is in the run position and the spindle is on.

Attachment 317034
The mount is made from SS tubing and acts as conduit for the wires. It is height adjustable and swings 90* with one knob that clamps on the tube.

Attachment 317036
You can see the fan for the main panel in the top right of this pic. It, and a larger 4" one on top of the electric motor, are also hooked to the vfd relay output and only come on during spindle run command. Also seen is a shotgun style touchless fuse holder, 24v power supply, and heat insulation behind the drive itself.

Attachment 317040

Attachment 317042

Attachment 317044
This is the only area im iffy about... I had to JB weld a small magnet to one of the unused pulleys for the proximity sensor. It doesnt seem to have effected the balance of my spindle at all as it weighs virtually nothing. But im wondering if theres a better way to do it. Also, backgear will read the same RPM so you have to divide by about 8 to get the correct speed.

Attachment 317046

More pics and possibly a video of operation to come, please let me know what you guys think!

[sohcpwr]

Below is a pic of the finished system with the cover on. Next thing im working on is a clear cover over the VFD screen. The drive can be set to display amperage and it would be viewable, along with any fault codes, without taking the panel cover off.

Attachment 317054

Attachment 317056

[eman5oh]

The install looks great, I have the same vfd on my Boss 5 Linux CNC conversion. I have been unimpressed with the vfd performance. Mine seem to take 4-5 seconds to spin up or down the spindle to full speed with out tripping how does yours work?

[sohcpwr]

You probably know this already, but without a braking resistor the drive can only spin down the electric motor so fast without faulting. It basically becomes a generator and the current generated has to go somewhere other than back into the drive. As far as speeding up, there are parameters in the setup that should allow you to speed it up as fast as youd like without faulting out. This is assuming you purchased the correct HP drive for your motor. Mine is a 3hp vfd on a 2hp motor so it has no problems speeding up on the somewhat aggressive curve i have programmed. The braking time I also set somewhat aggressively and it still doesnt fault. Maybe my expectations are less than yours but I am very happy with it. For not much more than china prices, you have a quality Westinghouse drive.. presumably made in USA?

[eman5oh]

I am running a 2 hp vfd on a 2 hp motor, I guess I should have up sized it, I turned up all the parameters and the acceleration and braking still leave a bit to be desired. If I replace it, it looks like I may opt for a 3hp model that will accept a braking resistor. The braking only trips on mine if i set the decel to 4 seconds or less and spin the mill up to full speed.

[sohcpwr]

I thought the 2hp drive (TECO) does accept a braking resistor? Another thing to think about for a home shop machine thats not making parts for production style money... the starting current is drastically reduced by accelerating the motor up to full speed. This not only saves money on the electric bill, but is easier on the motor and everything connected to it. For myself, I cant see the 3 seconds or so it takes for it to spin up to full speed to outweigh previously mentioned benefits. On another note, what would you guys think an acceptable starting price would be for a setup like this? i.e. what would you want to pay?

[eman5oh]

Only the 460 volt L510's can have a braking resistor. Being for hobby use the time it does not bother me in the slightest. My problem is that I want to either get ridged tapping or a floating head working under cnc control. While I don't think it is a show stopper it will make it more difficult and I believe blind holes will be out of the question. Your install look very professional and I think around 1000-1500 depending on options would be a good target price. You will have some compition though, I see these on ebay Servo Variable Frequency Drive VFD 3 HP 230V 1 Phase Bridgeport Mill Milling | eBay