Member postings for John Haine

Any majss added above the CG of the pendulum moves the CG up and effectively shortens it. For a given added mass its effect is maximum half way down the road, minimum at the bottom and top.

The phase difference between the impulses and BDC of the pendulum. In your case with a sinusoidal drive the maximum drive torque is ideally at BDC.

Standard expression for effect of phase error on fractional change in rate is

Tan(phase error)/2Q

Which is one reason why high Q is desirable.

Metric now.

LVDT = linear variable displacement transformer

If you want a 3-phase induction motor and VFD then from my experience it would be well worth contacting Newton-Tesla. But didn't the original have a 440W DC motor? If so an induction motor might be hard to squeeze in.

The second seems to be just an ELS at the moment though implied it may be upgraded to full cnc.

Phase change heat storage is the way to go though probably beyond the scope of home construction.

https://sunamp.com/plentigrade/

**LINK**

Bill, that's a cool app!

I can't help you with a shortcut Michael, but what would you do if you had one? The phone will select the "best" serving cell on your registered network and I don't think there's any way to change that and make it use a different one, unless you changed network. Something like Netmonitor could help, or you could install the Opensignal app.

https://www.opensignal.com/apps

**LINK**

Don't measure runout under power. Any resonance will exaggerate the measurement.

A data point. We have a modern large storage heater in our kitchen/diner which is heated at night probably for 4 hours from cold consuming 3kw, so total of 12kwh. That keeps background heat in the room until evening. You might use one a third the size for a small room so 4kwh. I don't think a 300w solar panel will cut it in winter daylight.

Your existing motor is probably a split-phase type where the start winding has a considerably higher resistance than the run winding, so the current in it leads in phase to provide some directional starting torque. These motors often don't switch out the start winding, I guess the induced voltage in it once the motor is running reduces the current anyway so it doesn't get too hot. I briefly owned a bandsaw driven my one of these.

Fans in cooker hoods are driven by induction torque motors, which have a relatively high resistance rotor giving highest torque when stalled. You can speed control these by varying the drive voltage, they are very inefficient. As NDIY says you can't generally vary the speed of an induction motor by changing its drive voltage, only frequency.

A stepper motor powerful enough to drive a bandsaw would be expensive and incredibly noisy.

I'm afraid that you are stuck with the current motor if you can't physically change it. It's just possible that you might be able to find a 3-phase unit with the same basic frame and fit the end-plate, of even just transfer the stator and its windings (the rotor won't know if it's single or 3 phase). Or use the end plate to adapt a DC motor.

But I should ask: What process would best show that the timing of a period is being recorded accurately?

If you have a GPS 1pps source, use your measurement system to log a few days periods and compute the Allan Variance (using Timelab or Stable32).

"limited by the 32kHz frequency of its output. This would yield about a 3us least count per second"

32kHz is a period of 31.25us?

Another undocumented feature of Mach3 Turn is that it does support G31 probing. I use this for setting up tool tables, ad-hoc X axis referencing, and referencing Z to the RH end of the stock as I have a sensor which senses contact between any tool and the work (as long as it's metal).

Tick use spindle feedback in sync mode. And r3.043.062

Still, Mach3 Turn is a new variant for me. As I read here, others seem to use it OK (reservations about one pulse/rev and threading duly noted) but there are bits of it that just do not want to play. OK, moving from screen to screen is cumbersome but I'm sure I could get used to it,

If you don't mind doing some screen development you can add shortcut buttons to speed this up.

but showstoppers at the moment are that having run a complete gcode file successfully, I can no longer jog.

That's weird and I haven't seen it before.

..... Having to restart Mach3 means that repetition work is awkward. And why won't Mach3 actually use the index pulses at all, when the diagnostic screen shows that they are arriving?

You have to set some tick boxes in "general config", I'll check what they are.

Edited By John Haine on 18/09/2023 21:48:02

Opinions differ. My Super 7 threads fine with Mach3 though I don't push the DoC much. There's usually no hurry.

Though I have to use 2 screens, manual and auto, I don't have the issues you describe. I'll have to check which version I am using.

I still use Mach3 as I'm used to it and have developed a good set of tool setting macros. I first started with it in 2012 I think, and starting again I wouldn't choose it now since it is unsupported. I'm using a UC100 motion controller, Win10 and a dinky Dell mini PC. At some stage Microsoft will do an update that breaks Mach3 and with no one to fix it that'll be curtains! Starting again I would use probably UCCNC, or maybe Mach4.

Well just to be contrary...

I converted my lathe to CNC well over 10 years ago using Mach3 broadly inspired by Tony Jeffree. What I didn't do was leave the handwheels in place and more recently I replaced the topslide with a solid toolpost mounting. I therefore have to do ALL my turning through the CNC conversion but it's no sweat at all! The only things that I have written g-code for are some specials that can't easily be done using the Mach3 wizards, but the latter cover the vast majority of operations you are ever likely to to do on a lathe. If the wizards don't cover it I can use the MDI to input just a single gcode statement, for parting for example; or I use manual control via a game controller which has a couple of joysticks and sundry buttons. Even just for casual jobs, "just turn XX.XX mm of the diameter of this bar for YYmm" this is so much easier, just reference the lathe, choose the tool, select the wizard and you're off. I had to learn to do all this because manual control wan't an option, but I soon realised it was no loss.

Actually there is one handwheel which is the rack&pinion drive for coarse carriage positioning, but that's rarely used once the lathe is referenced.