Gunsmithing Power. . .

[LRI]

Bit of a scare this afternoon. Garrett powered up the lathe and after a single pass on a barrel the machine started crashing and spitting out all sorts of various alarms.

Thankfully the barrel wasn't damaged, but it took us the better part of the afternoon to get it sorted out.

Turns out it was power delivery. I had one leg consistently reading low voltage on the machine. Tracing it back to the panel showed a loose connector. Odd as they never get touched, but its right next to two very buzzy air compressors so maybe it rattled it loose.

Thankfully the failsafes in the machine did their job and shut everything down in the effort of protecting the electronics.

My reasons for sharing this are simple. Modern CNC's will make the effort to diagnose the problem for you in the form of trouble shooting codes. With manual equipment you don't get this luxury and things like low voltage on 3 phase power will raise hell with motors in a hurry if left unchecked.

Next time your bored, open your panel and snug up all your wire connections. If you ever run CNC's and get alarms that callout for low voltage and servo voltage current drops or hydraulic pump voltage low, get out your meter and start probing main terminal connections. If you get a low leg, check your hardwire connections!

Could save your checkbook from a major azz kickin!

C.

 

[excaliber]

Re: Power. . .

PM sent

 

[_shawn_]

Re: Power. . .

1 thing to remember is electricity vibrates and if the electrician didn't tighten everything up really good it will loosen up. half my commercial/industrial service calls are from bad/loose connections that melted the connectors because they either weren't tight enough to begin with or vibrated loose over time and when the connection gets loose enough it'll start arcing which will cause enough heat to build up to either melt the connectors or in the right instances start fires

 

[my human host]

Re: Power. . .

The Mori lathe at work gets shut down rather quickly if the power starts blinking or an electrical storm is moving through. The green button guy (not me) gets to push a broom until things settle down.

It's roughly twice the size of my pickup. I don't think I'd want to be standing next to it if it crashed.

 

[JJones75]

Re: Power. . .

Just like your trigger screws , a little dab of nail polish on all the terminal pugs will help alot of trouble down the road. We had the same issue last year with a huge Ingersoll 5 axis at work

 

[mdesign]

Re: Power. . .

Good post Chad...I do a thermal image inspection on similar pieces of equipment. Makes it pretty easy to find a loose connection (hot spot) before it causes an issue. Power blinks can cause a lot of pain for me.

 

[Powermac]

Re: Power. . .

A copper conductor, tightened up to specs should really not vibrate loose over time, use some cable ties etc, to alleviate pressure/vibration. Sure happens sometimes still. Depends on the type of connectors used, also single core cables are much more prone to vibrate loose then multi core ones.
In most cases it's caused by not using the right equipment for the enviorement it' in, or poorly executed work by someone.

It's a good tip checking over sometimes yes, to avoid burnt contacts and possible fire sources as they can become.

 

[LRI]

Re: Power. . .

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: my human host</div><div class="ubbcode-body">The Mori lathe at work gets shut down rather quickly if the power starts blinking or an electrical storm is moving through. The green button guy (not me) gets to push a broom until things settle down.

It's roughly twice the size of my pickup. I don't think I'd want to be standing next to it if it crashed. </div></div>


Being on the North Face/Western Edge of the Black Hills we get some rather violent storms here. Especially in the industrial park as were sort of in a funnel for the wind to whip through. As you stated, when the weather turns to chit, I power everything down and push brooms (Here I'm the programmer AND the "Green Button Guy" (lol!) ) till it decides to be nice again.

I had a lathe once that absolutely HATED florescent lights. The RF they give off would cause the control to intermittently go into arrest. Took a long time to sort out, but moving the lights another 12" up solved it. (low ceilings at that shop)

Weird stuff. . .

C.

 

[xs hedspace]

Re: Power. . .

Aluminum conductors are really liable to work loose from thermal expansion, and rapidly get an oxide buildup, which makes the connection worse,etc, sort of a Chernoble effect. There is a compound called No-alox which should be applied on the ends of aluminum wire before connecting, and you have to snug them up really tight. Friend of mine burned out a compressor motor, I tracked it down to a loose fuse in the emergency disconnect switch next to the compressor(lots of vibrations).

 

[Greg Langelius *]

Re: Power. . .

In the 1960's I went to USMC Engineer Electricians' School at Camp LeJeune. That was when professional electricity folks were first recognizing that aluminum conductors can be hazardous, causing oxidation in aluminum/copper bonds; and leading to resistance heating, when loads pull higher amperages, that can even/often lead to structure fires.

I am more than mildly surprised to read that aluminum is still being used as an electrical conductor in some places. Wherever I see it, I replace it if I can.

I'm not questioning how and why aluminum conductors are still in use, but I am suggesting they might be replaced with copper for some safety and other benefits. I'd say they really need to go if at all feasible.

Greg

 

[Powermac]

Re: Power. . .

Aluminum has it's place, used in industry, large cables, of multi core structure, pressed round, brushed down to remove the outer layer that has oxided, while applying a non occidating solution like Contax,. And connected to effect switches, with connectors ment for aluminum, torqued to spec.
In enviorment where vibration is not a issue, it's used because it reduces the cost a lot.
And is viable in such a application.

For use inside buildings, houses, machines etc it's a bit hazardous and should not be used.

 

[Greg Langelius *]

Re: Power. . .

Yes, I agree, a really good place for aluminum is in overhead HV power transmission. Many decades back, I did poleline const/maint (USMC), and railway (PRR) electrical traction/transmission const/maint, as well as bus/res electrical const/maint off and on for several subsequent decades. Jim Hubbell (Son of CEO Hubbell Electric) was in my USMC Engr. Electricians' squad in 'Nam.

 

[JJones75]

Re: Power. . .

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: C. Dixon</div><div class="ubbcode-body">

I had a lathe once that absolutely HATED florescent lights. The RF they give off would cause the control to intermittently go into arrest. Took a long time to sort out, but moving the lights another 12" up solved it. (low ceilings at that shop)

Weird stuff. . .

C. </div></div>

I remembered reading this today when a new mill at work was having issues (REPUBLIC LAGUN VMC-8740) , they had several lights on stands close to it , i suggested backing them up a couple feet and running it to see what happened , works perfectly now.

Thank you Mr Dixon for making this simple redneck look like a genius!!

 

[northern50]

Re: Power. . .

This is why we thermal image panels, and do physical PM's on our equipment. Good catch and good post, electrical especially gets overlooked in the PM department.

 

[MikeeBooshay]

Re: Power. . .

I used to be maintenance mgr at a large power plant, we melted 9 cables, each 1000 MCM ( about 3 " diameter ) into about 300 ft of underground conduit, 13,800 volts. Installed improperly, all 3 phases where installed parallel, like this :

aaa
bbb
ccc

The induced current between them, melted them in a few days. Glad that was under waranty!!!! Wish I had pictures of that still...

 

[71firebird400]

Re: Power. . .

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Mikee Booshay</div><div class="ubbcode-body">I used to be maintenance mgr at a large power plant, we melted 9 cables, each 1000 MCM ( about 3 " diameter ) into about 300 ft of underground conduit, 13,800 volts. Installed improperly, all 3 phases where installed parallel, like this :

aaa
bbb
ccc

The induced current between them, melted them in a few days. Glad that was under waranty!!!! Wish I had pictures of that still...

</div></div>

Wow, as an electrical engineer, I would've loved to have seen that

 

[MikeeBooshay]

Re: Power. . .

Didn't post it to one up anyone, but to reinforce the point. Electrical thing need maintenance too.

We used to use a thermal scanner twice a year, inspect any connection we could see. We always, ALWAYS, found something loose. As a result, all the electricians, were issued a torque wrench, and the work planning sheets dictated a torque value. Over time, we found less and less.

Most of our shops, mine included, were wired by electricians, without as high a QA/QC standard. As to Chads point, if something is different, figure out why.

 

[71firebird400]

Re: Power. . .

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Mikee Booshay</div><div class="ubbcode-body">Didn't post it to one up anyone, but to reinforce the point. Electrical thing need maintenance too.

We used to use a thermal scanner twice a year, inspect any connection we could see. We always, ALWAYS, found something loose. As a result, all the electricians, were issued a torque wrench, and the work planning sheets dictated a torque value. Over time, we found less and less.

Most of our shops, mine included, were wired by electricians, without as high a QA/QC standard. As to Chads point, if something is different, figure out why. </div></div>

I spend my days doing low voltage (480V) design so the medium and high voltage stuff is interesting to me. I'd love to get into transmission & substation design some day. Good point on the maintenance end of it as well; a lot of our clients seem to think a motor control center should last forever with little to no maintenance. Just because there are no moving parts does not mean you can close the door for the next 30 years.

 

[ScottWatkins]

Re: Power. . .

I was working on a Van de Graaff generator in the shop a while back. After finding the problem and correcting it, I fired it up to play with it. It made ALL of the machines in the shop dork up. They were doing the weirdest things. Luckily, none of them crashed. After powering them down and restarting, they were fine. The wire EDM wigged out the most.

We don't play with that in the shop anymore.

 

[_shawn_]

Re: Power. . .

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Mikee Booshay</div><div class="ubbcode-body">I used to be maintenance mgr at a large power plant, we melted 9 cables, each 1000 MCM ( about 3 " diameter ) into about 300 ft of underground conduit, 13,800 volts. Installed improperly, all 3 phases where installed parallel, like this :

aaa
bbb
ccc

The induced current between them, melted them in a few days. Glad that was under waranty!!!! Wish I had pictures of that still...

</div></div>

wow how long ago did that happen and how many got fired? i knew better then that when i was a second year helper