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Re: DC power supply grounding

 

Chris's advice is useful if you have high speed signals or analog signals that need to be protected from noise. If I am not careful, I will ignite a signal integrity war. Having been a EE designing high speed systems used on mobile platforms, it is easy to explain things that make it seem much more difficult to do well. In Chris's advice - you will want to make sure all users of the 12vDC signal get a direct pair of wires from the power supply and yes, you want to have no daisy chains of the supply wires. Also, you will note that I do not refer to the DC minus as "ground" - it is the return and we want to make sure we isolate it from the AC ground.

Always keep the AC side isolated from the DC side.


On Fri, Dec 29, 2023 at 6:34?PM Chris Albertson <albertson.chris@...> wrote:
No, the iron frame is a protective ground that eventually goes to the AC breaker box. ? its purpose is to short a stray wire to the ground. ?it is only for safety.

You do however need a DC ground point.? And not more than one of them. ? Tie the DC grounds together as one and only one point.? Likely this is done already.? So you need to find it. ? Do not daisy chain the grounds.? They all run to be point that is isolated from the chassis.

On Dec 29, 2023, at 6:17?PM, chrisser via <chris.kucia=[email protected]> wrote:

Brett's post on DRO grounding made me wonder if I should ask a similar question...

I'm doing some mods to my lathe involving a larger controller box to accommodate a typical Chinese RPM display and an amp gauge for the motor draw.

I bought a little 12vdc power supply board to power the RPM display - it's overkill (2A 12vdc supply) but I figure I may someday want to run some other 12v load and there'll be space in the box and capacity on the power supply.

The power supply board has 2 line inputs for AC and 2 outputs for DC.

Any reason I should ground the DC - to the lathe chassis the same way the AC ground is wired - sort of like you would do with 12vdc in a vehicle?


--
Buffalo John
Re: Magnetic DRO Reader Gounding?

Chris Albertson
 

¿ªÔÆÌåÓý

The shield ground is to be connected at one end only with the other end left not connected to anything. ?This means there can never be current flowing in the shield. ? ? Connect the shield to the Lathe¡¯s DC ground point.

On Dec 29, 2023, at 6:01?PM, CBJessee-N4SRN <cbjesseeNH@...> wrote:

The LMS lathe DRO kit has DRO reader heads with the coax cable shield tinned, presumably for grounding. My AC Panel is grounded to my copper cold water pipe (meets NH code), with both in the basement near my lathe. I can tie the DRO reader head coax shield into the same common ground. My LMS4200 lathe is electrically grounded via a screw into the headstock, with the lathe power cable plugged into AC mains. WIll this be sufficient to ground the lathe & DRO?

I¡¯m pretty good with Ham Radio grounding to avoid group loops (I have a lot of copper rods in the earth, all tied to my AC panel) but don¡¯t know the norm for DROs & lathes/mills.

BRET

Re: DC power supply grounding

 

The purpose of "grounding" is to provide a return path for a voltage to a safe place to keep a human from suffering harm - pretty simple.

The AC main ground should always be connected to the frame of the machine. The motor may be double insulated and if might be nearly impossible for AC line voltage to appear on a metal surface, but just in case, ground the machine to the AC ground pin.

The 12v supply - it should not be connected to the AC ground. You should isolate your boards so that they don't contact the machine ground. If you have small signals that need to be protected, use shielded cable and connect the shield to 12 return (minus) on both ends of the cable.


On Fri, Dec 29, 2023 at 6:17?PM chrisser via <chris.kucia=[email protected]> wrote:
Brett's post on DRO grounding made me wonder if I should ask a similar question...

I'm doing some mods to my lathe involving a larger controller box to accommodate a typical Chinese RPM display and an amp gauge for the motor draw.

I bought a little 12vdc power supply board to power the RPM display - it's overkill (2A 12vdc supply) but I figure I may someday want to run some other 12v load and there'll be space in the box and capacity on the power supply.

The power supply board has 2 line inputs for AC and 2 outputs for DC.

Any reason I should ground the DC - to the lathe chassis the same way the AC ground is wired - sort of like you would do with 12vdc in a vehicle?


--
Buffalo John
Re: DC power supply grounding

Chris Albertson
 

¿ªÔÆÌåÓý

No, the iron frame is a protective ground that eventually goes to the AC breaker box. ? its purpose is to short a stray wire to the ground. ?it is only for safety.

You do however need a DC ground point. ?And not more than one of them. ? Tie the DC grounds together as one and only one point. ?Likely this is done already. ?So you need to find it. ? Do not daisy chain the grounds. ?They all run to be point that is isolated from the chassis.

On Dec 29, 2023, at 6:17?PM, chrisser via groups.io <chris.kucia@...> wrote:

Brett's post on DRO grounding made me wonder if I should ask a similar question...

I'm doing some mods to my lathe involving a larger controller box to accommodate a typical Chinese RPM display and an amp gauge for the motor draw.

I bought a little 12vdc power supply board to power the RPM display - it's overkill (2A 12vdc supply) but I figure I may someday want to run some other 12v load and there'll be space in the box and capacity on the power supply.

The power supply board has 2 line inputs for AC and 2 outputs for DC.

Any reason I should ground the DC - to the lathe chassis the same way the AC ground is wired - sort of like you would do with 12vdc in a vehicle?

Grizzly is doing better - I hope!!!

 

Today, I just received the annual catalog from Grizzly by mail. It is very thick compared to what they sent me last year which was relatively thin with maybe just under 50 or 100 pages, not sure. This time it is a full 500 pages. I see it as an indication that Grizzly is doing well. I feel good about it. I want US businesses to do well..?

Just expressing my personal feelings,?
Prasad
Eastern PA
DC power supply grounding

 

Brett's post on DRO grounding made me wonder if I should ask a similar question...

I'm doing some mods to my lathe involving a larger controller box to accommodate a typical Chinese RPM display and an amp gauge for the motor draw.

I bought a little 12vdc power supply board to power the RPM display - it's overkill (2A 12vdc supply) but I figure I may someday want to run some other 12v load and there'll be space in the box and capacity on the power supply.

The power supply board has 2 line inputs for AC and 2 outputs for DC.

Any reason I should ground the DC - to the lathe chassis the same way the AC ground is wired - sort of like you would do with 12vdc in a vehicle?
Magnetic DRO Reader Gounding?

 

The LMS lathe DRO kit has DRO reader heads with the coax cable shield tinned, presumably for grounding. My AC Panel is grounded to my copper cold water pipe (meets NH code), with both in the basement near my lathe. I can tie the DRO reader head coax shield into the same common ground. My LMS4200 lathe is electrically grounded via a screw into the headstock, with the lathe power cable plugged into AC mains. WIll this be sufficient to ground the lathe & DRO?

I¡¯m pretty good with Ham Radio grounding to avoid group loops (I have a lot of copper rods in the earth, all tied to my AC panel) but don¡¯t know the norm for DROs & lathes/mills.

BRET
Re: A couple of home brew DRO's

 

I remember hearing that problem.??
Same thing can happen with DRO too.?
?The best is the optical type even today.
There was another type used a dial indicator and I'd type mic. Both was very reliable but slow to use.?

Dave?
Re: Tricks of the trade

 
Edited

For blind threading RH use reverse and cut from back side.?

You use a carriage stop move carriage to stop and ingauge the haft nut and start in reverse.? Now cutter will back out hole.?

Note this only works with a threading dial or it same thread as the lead screw.?
It does work use a dial indicator and manual turn the till at mark on dial indicator. Works about same but slower

Dave
Re: A couple of home brew DRO's

 

?
Nods, remembering back 1960's with the mechanical Travl dial's on some mills, skipping and guys scrapping parts, couldn't trust em...
In a message dated 12/29/2023 4:58:32 PM Pacific Standard Time, davesmith1@... writes:
?

Just keep in mind what you really need to your work. If step you into most machine shops looks great all tools have DRO'S most are not working.?

In the shop I had only the Bridgeport had DRO'S and air guns where band. They work for over 30 years.?

When work shop I made portable set. It was only handy for some type of work like snap rings in lathes and milling holes.?

Dave

Re: A couple of home brew DRO's

 

Just keep in mind what you really need to your work. If step you into most machine shops looks great all tools have DRO'S most are not working.?

In the shop I had only the Bridgeport had DRO'S and air guns where band. They work for over 30 years.?

When work shop I made portable set. It was only handy for some type of work like snap rings in lathes and milling holes.?

Dave
Re: MicroMark 7x16 Fault Notice

 

I have with this type of board pass .
It could a reostat having a dead spot.
Just by moving the reostat will clear the problem.??
This is same problem you find with a clock radio and the volume control.??

Next 1
It could even be with brushes.?
That easy check just remove and inspect.??

Next 2
I have disconnected the motor from the board and use a 12 volt battery charger to see if motor turns.?
If motor turns on charger then replace the board to match the motor. The motor will give data need for new board.?

Remember a new board will need to be adjusted for torque and speed. A better board will you better responds at lower speed.?

Good luck
Dave?
Re: A couple of home brew DRO's

 

Wow! Those look fascinating, but I think they're beyond my capabilities right now. Would be a neat project though.

On Friday, December 29th, 2023 at 6:55 PM, mike allen <animal@...> wrote:
A couple of home brew DRO's

 





Re: MicroMark 7x16 Fault Notice

 

This was also in that manual:

ATTENTION: The power supply system of the 120v AC machine has an automatic overload protective device. If the machine is overloaded, the
motor will automatically shut down, and the yellow lamp will light and the readout will display ¡°ERR¡± (if equipped).

IMPORTANT!
First, rotate the RPM to OFF (counter clockwise). The display should read four zeros (0000) and the
word ¡°STOP¡± should reappear in the lower right corner, if equipped. You will now notice the yellow
overload light has gone out. While it is possible to start spinning again simply by rotating the RPM
knob at this point, we advise you to push down smartly the Emergency Stop Button and investigate
the cause of the overload. Once you have cleared the situation, then, and only then, should you
begin the start up sequence in this section.
Note: the big red emergency stop button must be pressed smartly (with some force) to activate the
internal shut off system properly. If the green light remains lit, power is still available to the motor,
so be sure to press the red button hard-enough to shut down the power.

On Friday, December 29th, 2023 at 5:52 PM, chrisser via groups.io <chris.kucia@...> wrote:

According to the manual on their site, the fuse is a?F10AL250V, which I assume is 10amp.? There weren't any instructions about removal, so I assume it's a twist-off cap that holds a glass fuse.? Should be able to see if the filament is discontiguous if it's burned out.? Manual also says it comes with a spare fuse, so if you still have the original bits lying around, you may still have the spare.

I'm going by the following pdf, although I don't know much about MicroMark - just found with a google search.



On Friday, December 29th, 2023 at 5:44 PM, OldToolmaker via groups.io <old_toolmaker@...> wrote:

I have owned my MicroMark 7x16 MiniLathe for many years. I have been unable to start the lathe which is unusual as I have not had it happen before. I am receiving a ¡°fault notice¡± (yellow lamp is on). Could it be a blown fuse? There is a fuse socket present. How can I check the fuse? I don¡¯t have spares as I have never changed a fuse in the lathe for close to 20 years at least.
What fuse should I buy if I need one?
Any help is appreciated.
Dick


Re: MicroMark 7x16 Fault Notice

 

According to the manual on their site, the fuse is a?F10AL250V, which I assume is 10amp.? There weren't any instructions about removal, so I assume it's a twist-off cap that holds a glass fuse.? Should be able to see if the filament is discontiguous if it's burned out.? Manual also says it comes with a spare fuse, so if you still have the original bits lying around, you may still have the spare.

I'm going by the following pdf, although I don't know much about MicroMark - just found with a google search.



On Friday, December 29th, 2023 at 5:44 PM, OldToolmaker via groups.io <old_toolmaker@...> wrote:

I have owned my MicroMark 7x16 MiniLathe for many years. I have been unable to start the lathe which is unusual as I have not had it happen before. I am receiving a ¡°fault notice¡± (yellow lamp is on). Could it be a blown fuse? There is a fuse socket present. How can I check the fuse? I don¡¯t have spares as I have never changed a fuse in the lathe for close to 20 years at least.
What fuse should I buy if I need one?
Any help is appreciated.
Dick

MicroMark 7x16 Fault Notice

 

I have owned my MicroMark 7x16 MiniLathe for many years. I have been unable to start the lathe which is unusual as I have not had it happen before. I am receiving a ¡°fault notice¡± (yellow lamp is on). Could it be a blown fuse? There is a fuse socket present. How can I check the fuse? I don¡¯t have spares as I have never changed a fuse in the lathe for close to 20 years at least.
What fuse should I buy if I need one?
Any help is appreciated.
Dick
Re: Morse tapper in tail stock

 

They make them in Jacob's.?
I do have one handy at times.?


You like the price too.?

Dave?
Re: Are DROs worth the money/trouble

 

I use metal scraping or shim stock.?
Both will give a little fex for smooth sliding.

Dave?
Re: Are DROs worth the money/trouble

 

On Fri, Dec 29, 2023 at 12:15 PM, WAM wrote:
I was able to add a cross slide DRO underneath
I experimented with that approach but found that the DRO I used has quite a bit of friction.? It caused the "C" shaped arm to deflect to the tune of about .004", despite my best efforts to stiffen it up.? That would result in a .008" diameter error, too much for my taste.

The DRO is an iGaging remote reading model.? Other types of DROs might have less friction.? The iGaging capacitive sensor MUST have a good sliding electrical contact to the scale so it's not possible to reduce the sliding friction to zero.

I have a solution I'm working on.? I'll report on later if it works OK.
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