Surge Protection For Machine Electronics

[Jeff Wright]

Living in Florida we have MANY thunderstorms. I recently had our electric company install a meter-based surge protector that is supposed to protect motors from lightning damage but will not protect any circuit boards. While I do have surge protectors for our entertainment center equipment and computers, I currently have no protection against damage to those machines' electronic boards. I'm told surge protectors for 220 power is very expensive. Therefore, I unplug my 3520B lathe and Mini-Max combination machine whenever not in use. This means I am plugging and unplugging these machines sometimes multiple times per day.

Question: Will the act of plugging and unplugging these machines cause any damage or unusual "wear-and-tear" on the machines' electrical components?

[Matt Meiser]

You can get whole house surge supression, for example, http://www.apc.com/products/family/i...id=174#anchor1 Of course APC still recommends additional surge supressors for computers, etc.

Probably the worst thing plugging and unplugging is going to do is prematurely wear out the receptacles--think about how commonly use receptacles in the house get loose over time. Really not that big a deal if you replace them. And if you are using more expensive ones like twistlocks, they'll probably last longer than run of the mill 20A receptacles.

You could put a disconnect switch at each machine. I have one on my TS circuit and throw it when I'm changing blades or not in the shop. really no "electronics" on it.

[Jeff Wright]

You can get whole house surge supression, for example, http://www.apc.com/products/family/i...id=174#anchor1 Of course APC still recommends additional surge supressors for computers, etc.

Probably the worst thing plugging and unplugging is going to do is prematurely wear out the receptacles--think about how commonly use receptacles in the house get loose over time. Really not that big a deal if you replace them. And if you are using more expensive ones like twistlocks, they'll probably last longer than run of the mill 20A receptacles.

You could put a disconnect switch at each machine. I have one on my TS circuit and throw it when I'm changing blades or not in the shop. really no "electronics" on it.

Thanks Matt. The whole house surge protector is what I had installed by the electric company. My combo machine runs on 220 and does contain some electronics as does the Powermatic lathe. I also do use the twist lock type 220 plugs. So . . . is it your understanding that I am not doing any damage to the electronics by plugging and unplugging? I can always replace the outlet plugs.

[Dan Friedrichs]

There have been several reported instances of people getting zapped because they happened to be unplugging some piece of electronics at the same time lightning struck.

That being said, lightning/surge protection is probably one of the blackest magics in the EE realm, and subject to intense debate. In my opinion, there is very little affordable technology that can offer much in the way of real protection. I leave everything plugged in and just make sure my insurance covers any losses or damage - I think that's the safest course of action for both my electronics and myself.

If I were to do anything, I'd take Matt's suggestion and install a good-quality knife-switch disconnect.

[Matt Meiser]

I'll let the experts chime in (I have an EE degree, but write software), but its no different that throwing a disconnect switch or turning off a breaker. And that's generally recommended as a good safety practice.

[Greg Magone]

You can throw the circuit breaker at the panel rather than unplugging the machines if you like.

Are the circuit boards in your machines energized even when the machine is not in use? If not, I don't think you need to worry about surges. Surges generally cause harm when the boards are powered and not when they are off. Household electronics, such as computers, televisions, etc, stay energized all the time, even when the machine is off. Your machines may completely shut down when you turn them off.

[Ken Fitzgerald]

Jeff,

I unplug and if I were you I'd continue the practice.

I had the opporturnity to see what lightning does when I worked air traffic control maintenance in the Navy at NAS Meridian, MS. Lightning struck a 1/4 of a mile from the precision approach radar but ran in the ac power lines. Lightning will jump across a turned off breaker without even exerting itself.

Even when turned off, the 3 phase inverter on my PM3520B has power applied to it. I simply unplug it. If the connectors wear out over time....$40 worth of connectors....cheap insurance compared to the cost of the electronics IMHO.

[Jeff Wright]

Y

Are the circuit boards in your machines energized even when the machine is not in use?

Greg, all I can say (not being electrically or electronically literate) is that my Powermatic lathe has a small red light on when the machine is not switched on. So in answer to your question I would say yes, they are energized when not on. As for the MiniMax 410 combo machine, it does not have any such small lights.

[Bill Huber]

That being said, lightning/surge protection is probably one of the blackest magics in the EE realm, and subject to intense debate. In my opinion, there is very little affordable technology that can offer much in the way of real protection.

I will sure agree with this...

When you think about lighting bolt being 25 miles long or longer jumping across a breaker is nothing.
People all the time put protectors on their PCs but it will really do nothing for a lighting strike. They will also unplug the PC but leave a phone line or cable connected and that will eat the whole PC if struck by lighting.

Unplug the device is about the only way you can protect against lighting.

[Jeff Wright]

I leave everything plugged in and just make sure my insurance covers any losses or damage - I think that's the safest course of action for both my electronics and myself.

Dan, the older I get the more I dislike inconveniences. Having my electronics get fried for me would be a hassle (finding, then ordering the part, the delay in its arriving, potential frustrations installing the device, and the higher likelihood of my killing myself with stray current than being hit by lightning, etc.). I suppose I will continue with my plan of plugging and unplugging. I am just not sure whether doing so puts a wear factor on the electronics themselves each time they reset (or whatever that clicking noise is when plugged in).

[Cliff Rohrabacher]

Lightening protection is a whole different animal from mere surge protection.
For lightening you need a really robust and fast dump to ground.

http://www.iceradioproducts.com/3.html
http://www.polyphaser.com/
http://www.eham.net/reviews/products/17

It's just not the same as the surge protectors one finds behind household electronics.

[Carroll Courtney]

Then there is "Brown Outs" which happens alot where I work but not where I live.I don't understand it,but I'm sure the light company does.---Carroll

[Thomas Syrotchen]

Jeff,
To answer your original question, if designed properly, unplugging any machine once a cycle stop has been pressed and allowed to complete should not negatively effect the machine. In other words, I hit stop on the lathe and it comes to a complete stop and then I undo the twistlok plug and something bad happens to my lathe, the manufacture and I would not be having a pleasant conversation. If you turned off the TV shouldn't you be able to unplug it? I have a hard time really coming up with anything that would damage a powermatic lathe after it comes to a complete stop by unplugging it and breaking the circuit is the best form of protection.

[Ken Fitzgerald]

[QUOTE=Jeff Wright;1184278]Dan, the older I get the more I dislike inconveniences. Having my electronics get fried for me would be a hassle (finding, then ordering the part, the delay in its arriving, potential frustrations installing the device, and the higher likelihood of my killing myself with stray current than being hit by lightning, etc.). I suppose I will continue with my plan of plugging and unplugging. I am just not sure whether doing so puts a wear factor on the electronics themselves each time they reset (or whatever that clicking noise is when plugged in).[/QUOTE]

Jeff,

On my PM3520B, when I first plug it in....if I immediately try to turn it on....it won't...but after few seconds if I try to turn it on..it will function normally. I believe this is normal as the 3-phase inverter circuits require some charge time. On my PM3520B...the RPM light remains on after you turn the machine off using the switch indicating some of the electronics are still energized.

In my opinion based on my 40 years of electronics experience, turning it off using the switch and then unplugging and plugging it in shouldn't have any effect on the electronics and is a sure way to prevent lightning and electrical variations (surges and brownouts) from damaging the electronics.

[Jeff Wright]

In my opinion based on my 40 years of electronics experience, turning it off using the switch and then unplugging and plugging it in shouldn't have any effect on the electronics and is a sure way to prevent lightning and electrical variations (surges and brownouts) from damaging the electronics.

Thanks Ken. That's the route I am going to follow.