Lightning and Surge suppression

[3d_danny]

Now that my Alpha120 bot is together and working, I was wondering what the other botters were doing in this area.(Lightning and Surge suppression)

Reason asking is that we are currently involved in a rather nasty lightning/thunderstorm. I shut the bot down and pulled the disconnects for my own piece of mind.

Since the control panel is hard wired into the 120v and 240v AC circuits, surge suppression is a little difficult.

Protecting the computer is somewhat easier with suppression strips and a good quality UPS.

In a busy shop, shutting down a cnc machine is usually not an option. What is a good standard operation procedure?

Dan

[elcruisr]

We run our 'bot in central Florida, the land of lightning. We use a commercial grade ups for the computer and monitor. From our electronics techs (among other things we build radio stations) we put a voltage diverter on the power supply for the PRT Alpha controller. This diverts overvoltage to ground and they are actually very affordable. Our logic (we hope and it has worked so far) is that in a lightning surge event it will protect the box as well as it protects the electronics we normally install these on at transmitter sites.

One thing we were told by the Fire Inspectors was to never use multiple surge suppresion devices on the same line such as a strip and a ups. It will fail inspection and they claim it can cause a fire.

Eric

[3d_danny]

Eric,
I am very familiar with the lightning in Florida. I worked for 15 years in Sarasota and Manatee counties maintaining high frequency carrier lines running through rural ares. Lightning is pretty amazing stuff.I've seen lightning turn the center of pine trees to charcoal. I've seen lightning evaporate the copper and leave the insulation untouched in transmission cables. I was thrown about ten feet by standing next to a field fence with my arm touching the wire and lightning hit within 5 miles. My arm and shoulders hurt for weeks. The hazards of working in rural central Florida....

Are there voltage diverters made for both 120v and 240v? Are these installed at the distribution panel or at the control box? Where might I be able to purchase or read more about such an item?

I had a several servers in Sarasota that we always ran double protection. After losing a rather expensive commercial UPS to lightning, we decided to run a surge suppressor in the line feeding the UPS. We never lost another one after that. I would be curious to hear from the Fire Inspector as to how it starts a fire.

Dan

[elcruisr]

Dan, never got an answer about how, only it was a code violation and we had to remove what we had. I can get the info on the equipment next week at the shop. You can get it in either voltage and it just needs to be installed between the breaker and the control box. We have ours at the box.

Eric

[rookie432]

Dan,
In my Day time life I am an electrical distributor. I sell TVSS (transient voltage surge supressors) devices. I put these in major manufacturing facilities that have equipment way more expensive than our shopbots. They are mounted on the main distribution centers powering the facility. I also sell these for residential applications for 120/240 volt systems. They require a 30a 2pole or 50a 2pole breaker in the panel to feed it. This breaker has to be mounted in the first position on your panel directly below the main. The tvss unit is capable of taking a lightning strike overvoltage to ground and protecting everything downstream connected on your panel busbars.
There are a couple of backdoors that overvoltage can get in, primarily telephone lines and cable tv lines. You can buy a good commercial grade 120/240 Tvss device capable of 80k per phase for around $350 you can also get ones that have feeds for tv/and phone lines.
Intermatic sells whole house systems for around $200. Check out Intermatic's website and you might find a local distributor.
For more commercial grade units try "United Power"
These will also help with Transient overvoltages such as motor circuits that get jammed and start doing funky things with your line voltage. This can damage sensitive electronic circuits.
Don't buy a lighitning arrestor. These are not guaranteed to protect sensitive electronics. These are mainly designed to protect against catastrophic loss of power and motor circuits. (I have an engineer who just learned this lesson the hard way. Approximately $60,000 worth of sensitive electronic drives lost because he didn't understand this when specifying protection on his gear.YEEIIKES)
I still reccomend a ups device for the computer and control box because the tvss doesn't help with a power outage right in the middle of a 3 hr cut file.
If you need more info just e-mail me an I'll try to help.

Bill

[beacon14]

What good would a UPS do on the control box if power goes out, unless you can also keep your spindle running? If the power to the router goes out, I want the 'Bot to stop moving also.

[rookie432]

Good point David,

Two options, Small Ups for the computer only, or larger ups for computer,control box and spindle, however you can run into some cheddar for a ups large enough to do your spindle too. I just priced a 3500w ups 90min battery backup and we were into about $4500. When we get into that kind of money I start looking at generators with aoutmatic transfer switches.However w/a generator setup a tvss device is a must. Generator voltages are not good for electronic circuits either. People don't realize this and and find that after repeated generator use their big screen tv's, cumputers, etc... don't hold up.
It also depends on the quality and features of the generator. I would reccomend a generac generator system. They are widely used for hospital circuits. Price is fair and they make their own Auto transfer Switches for their generators so lagtime is very small. Not sure though how a half second transfer time would effect our setups. Would have to research it.
These options really are only good if down time for your facility is very expensive. Manufacturers can lose anywhere from $10000 to $50000 per hour they are down so these options are fairly inexpensive for them.

Bill

[gene_marshall]

We were recently hit with a power spike and subsequent electrical fire.

the computers with ups were saved.
the others had blown their power supplies.

we were happy to have the ups's for this.

but generally, when the power goes out, the router stops, the controller stays on and the computer stays on.
but the shopbot stops where it is and we don't lose our coordinates.

this has saved many projects for which replacing a hardwood glue up would have been costly.

We use Belkin ups, bought from tiger direct.
and have been happy.

gene

[bleeth]

The power spike that hit my office a few weeks back came in exclusively through the hot wire and not the neutral as lightning usually does. The UPS let it right through since all it was registering was electricity flowing through the correct leads and NOT the fact that the voltage was too high. This did result in a loss of computer power supply as well as most of the other electronic items in the office. This problem had it's roots in a rewired panel that had not been properly marked by the electrician. I found out the hard way that a breaker he had marked west wall was really office outlets and a position left open was a three phase high leg.

That is when I also learned about the limits of surge suppressors.

Dave

[3d_danny]

All great info. Thanks for the responses.

We survived the storm so back to making scrapwood and kindling<g>

Dan

[elcruisr]

The voltage diverter we are using is an Edco. They have dealers all over the place. Their website is

www.edcosurge.com (http://www.edcosurge.com)

I don't remember the price but it was pretty affordable.

Eric

[gene]

What about surge suppressors that the power co has at the meter ? do you think this is a good idea ? I have one on mine and the power co says it will protect the whole shop. Any experiences with this kind ?

[fleinbach]

I would think if the power company was supplying a surge suppressor it should work fairly well. It would be hard for them to claim your surge suppressor didn't work with them supplying it.

[ron brown]

And, I trust the government has MY best interests at heart too!

Sure,
Ron

[gene]

Ron,
What .... you dont think they have your best intrest at heart? I'm shocked!!!

[dingwall]

What size of UPS is needed to run a computer, monitor and SB controller? I picked up a 400 Watter and the controller trips it when the steppers are running. We're thinking a 1500 Watt is what we need, but they're pretty expensive.

Any thoughts?

By the way. I was using a surge suppressor thinking it was enough. We lost a new computer - maybe it was a spike, maybe not, but that made me take a UPS more seriously.

As explained to me by my tech - a UPS is more than a surge suppressor, it runs the incoming power through a battery charger which continously charges a battery, the battery supplies an inverter that supplies the power to the computer. This is why the power is so smooth and consistant. Plus it's close to impossible for a spike to get past the battery.

[dvanr]

I would start by adding up what everything draws in terms of current , computer , monitor and controller. Multiply that by the voltage you are using, that will be your bare minimum in watts. You will probably have to go higher because of in rush currents when the steppers turn on. If you want to find out what that is you'll need a clamp on ammeter with max hold reading capability.

It's going to be expensive.

[gerald_d]

Sheldon, I think your 400 Watt is only slightly underpowered. The internal power supply feeding DC to the stepper circuit is probably 300W (you can look on its label) The computer probably draws less than 200W (there could also be a label) There is no need to run the monitor through the UPS.

I would think of getting a second 400W unit and dividing the circuit for the two UPS'es - less further investment.

[bill.young]

Hey Sheldon,

We talked about this at the Florida camp last year because Jorge's power in his shop blinks a lot. One of the problems is that you can keep the computer and SB controller running with a UPS but the router or spindle dies and you're pushing a dead bit through the material.

David Allen (I think) suggested looking into the UPS's that have a serial or USB connection...so that it can tell your computer to shut down then the power fails...and somehow using that signal to trigger input #4 in the control box...the e-stop circuit. Then when the power blinks the tool will stop moving and wait for further instructions.

If it looks like an extended outage you'll have time to shut the software down normally and you won't lose your location, and if it's just a quick blink you can start it going again when the power comes back on. Not sure how all this would work with the Alphas but it seemed like an interesting idea.

Bill

[gerald_d]

Why as much as a serial or USB connection? Why not just hold a relay with the incoming line (hot?) and put the E-stop through that relay's contacts? If the incoming line blinks then the relay drops and the system does the correct shutdown.

[rjguinn@optonline.net]

Sheldon,
For several years I've been using 2-300w off the shelf UPS units to backup & protect.1-computer & monitor; 1- control box to battery backup outlet at rear of UPS & SB power supply to non backup outlet also on rear of unit.Install a standard voltage relay using the same power source as your UPS unit uses & wire power on-contacts open between an input & ground;power off SB stops-computer,monitor & SB controller on.Your power supply to steppers & other standard voltage items are off.Your on screen cut file line position will be shown on screen. It works!

[ron brown]

Two quick thoughts here - I have used a relay to trip the E-Stop when the router looses power and have also found larger old UPS units with bad batteries very reasonable at computer salvage places.

On one I changed 4 -12V small batteries with 8 Golf cart batteries. That particular Pure Sine Wave unit had a fan and would run continually as a backup. It was a 1600 watt unit. Cost of new, large batteries was much more than the old UPS.

Ron

[bill.young]

A similar circuit on a vacuum system could be handy ....you're in trouble if the circuitbreaker kicks out on your vacuum but everything else keeps going.

[ron brown]

Bill,

My shopVac, the one I used for a while for dust collection had a large flat top that "sucked in" when the hose clogged. I put a micro-switch on it as well as the relays to activate the emergency stop.

A vacuum hold-down should be monitored also. A diaphram and a microswitch, laser pointer activating or killing an opto-transister or cavuum switch would work there, in addition to the circuit switches.

Manual or time delay over-rides will need to be incorporated at times to get the devices started and working properly. The safety and activation process needs to be considered and properly implimented.

There are many ways to monitor the necessities for Proper operation of the tools. Sometimes it just takes a little thought and a different approach than what someone else has done.

Ron

[gerald_d]

Just remember that Sheldon actually asked for thoughts on the size of UPS'es - maybe we have strayed from that.

[jay_p]

I too have a question similar to Sheldon's, and as Gerald pointed out his question was never answered here. So to revive this old thread, does anyone have any thoughts or advice about the size of UPS needed for the computer and SB control box.
Thanks for any ideas.

jay

[patricktoomey]

Jay,

I run mine on an APC BackUPS Pro 2000 with extended runtime batteries. This unit is way overkill but I had it laying around from a past life so I used it. With that unit I only light up 1 or 2 of the 5 bars on the power usage meter on its face and it runs for over an hour. That's with at 19" monitor also plugged into it and turned on. I would think that based on the power supply in the control box and and average 300 to 400 watt supply in a typical PC you could get away with a 1000 VA unit. If you just want a few minutes to shut the machine down in an orderly fashion then you don't need the expensive units with the big batteries. I have always been partial to APC brand UPS's since they have saved my butt many times in data centers that I've run. If you go to their site at www.apc.com (http://www.apc.com) you can enter the wattage of the equipment you want to supply and the desired runtime and it will tell you what unit you need.

[jay_p]

Thanks Patrick. Am I correct in assuming that a UPC also provides a more stable power supply? So not only would it provide power for a certain amount of time if you had an actual power failure, but it would provide a more stable source, without voltage fluctuations under normal circustances. Is this true?

Jay

[andyb]

Yes, you are correct. I had an old UPS that have a audible alarm on it. When there was a power fluctuation it would sound. I was surprised how many times the power fluctuated.

Andy B.

[patricktoomey]

Andy is definitely right, my alarm sounded so often I disabled it :-) It kicks over to battery power everytime my compressor kicks on or when I start my table saw. Both of those items draw enough starting current to make my voltage drop by enough to trip the UPS. That amount of sag should not crash the computer but it also can't be very good for it so I feel better with the UPS on there.