Topics include, Machine Tools & Tooling, Precision Measuring, Materials and their Properties, Electrical discussions related to machine tools, setups, fixtures and jigs and other general discussion related to amateur machining.
Finished wiring it up today; probably a dozen code violations on this board...
The rotary cam selection switch didn't work how I want so I took it apart and put it together again. That's 4 hours I won't get back!
It switches the direction control signal as well as the power between the drill and the lathe.
To the right of the VFD is speed control dial and emergency stop button. I had one and it seemed the right thing to do.
I haven't found any way to switch it off completely. There is a 'sleep' mode but the cooling fan and indicator stays on.
If I unplug it, the workshop breaker pops when I plug it back in. The capacitors I suspect.
the sensors are a good idea...scrape the paint off and put them in the CENTER of the housing body..not near the shaft(s). figure out a way to hold them in constant 'touching' contact with the frame of the motor...this does not mean 'glue' which is a thermal insulator.
centripetal force goes up with the SQUARE of the velocity....
two times the rpm = 4 times the load...
I don't necessarily follow that a heavy frame motor is better for cooling..you put heat in, you have to get heat out...
granted the older motors were probably 'overkill' on some of the design, but when things start to heat up because of low frequencies...it is going to get hot from the inside out..it if weighs 10 Kg or 20 kg.....
worry about heat at low rpm and flying apart at higher. Heat would be my biggest worry.
Remember that by the time it is 'too hot' on the outside...it is already much too hot on the inside...
I would use the VFD for +/- 20% of rated speed and use gears for the rest. After all, what you really need is 3 ph output..nothing else..
Your wiring is a nice looking setup but ----- why do you have rotary cam switches to change direction?
you should do that with the VFD...generally forward....since you very rarely run the lathe in reverse and almost never a drill press.
If one motor runs the opposite way and you need to change directions when changing over...then just reverse one of the 3 phase leads on one of the motors...and both motors will run the same way on one VFD setting...and you can forget it.
Before it is over with, you will have more invested in plugs and connectors etc; than just purchasing another VFD for the drill press...
The rotary switch isn't for reversing, it's to change the vfd over from the drill press to the lathe. 3 power lines and 1 signal line.
It used to be the reverse switch on the drill; I added it because I often use the drill press for tapping.
Now I use the old start/ stop/ reversing lever on the lathe as the control for the vfd when using the lathe, and I have a rocker switch on the drill.
I reverse the lathe a lot; for polishing with emery because the grip is safer, and when threading as I don't have a threading dial.
The larger motor has more cooling surface is my thinking.
I set the minimum frequency at 15Hz, 30%. It seems pretty slow to me.
Almost everything there is leftover and recycled material, I only bought 1 new outlet, and made the control knob from brass just because.
I got this VFD cheap because it had a low start price and I was the only bidder, but mostly I would have to spend at least $150 for a 2hp cheapo unit and twice that for a quality one like the Lenze.
I considered hard wiring things, but this way I have the option to use my 3-phase extension cord it I want to move one of the machines for mounting something oversize, or move it out of the way of other work.
Since the VFD output has no neutral, it's not correct that I used the 5-pin outlets and plugs. their are 4-pin [3+earth] ones for this, but all my 3-phase things use 16A 5-pin.
