for you electrical/technical gurus

Carol Reed

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Location
Coolidge, AZ
I am cautioned to not run my Jet 1642 lathe off my generator because the 'dirty' power will blow the electronic board (handles variable speed). And I can't get my head around what to do about it. So....

1) How do I determine how clean the power being generated is?

2) Then, how do I recognized dirty power from clean power?

3) What do I do about it if it needs 'cleaning'?
 
I keep a large UPS around to plug my electronics into when I need to run them from the generator I have. Spikes and line noise are the most typical issues with generator electricity. It looks like your lathe has a 3 phase inverter built in. I'm not sure how many amps/watts your lathe takes, but I assume 15 - 20, which would require a pretty large/weighty UPS.

A of it depends on the quality of the signal coming from your generator. You'd need to find someone with an oscilloscope to "listen" to the signal and see what it's generating. The person running the oscilloscope will know what you need to look for (spike, type of signal). The more high end generators typically have better conditioning circuits to create cleaner electricity for home electronics. I'm sure there are some reviews of this on the interwebs, but I haven't searched for any.

You may be able to get a line conditioner as well, but haven't searched for those either.
 
Carol, "dirty" power has a lot of "noise" in it -- surges, sags, sine wave distortions, etc. Many electronic items (including newer ballasts) can't handle dirty power for very long without failure. I'm not real familiar with this , but I have heard that power can be cleaned up with capacitors, and or by installing an isolation transformer, The latter is what we used in it place where I worked, which worked really well, and isn't really cost prohibitive I would suggest that you contact a qualified electrician in your area and get their opinion as to which way would be better for you. This isn't something that you should try yourself if you are not familiar with working with electricity. Not trying to scare you , but I want you to be safe. And yes, the dirty power will damage your controller over time. I'm not really as versed in this area as someone that does it all the time. I hope this helps you a little.
 
Thanks so far, guys. Here is more information. The lathe is a Jet 1642 220v 20amp feed required. The generator is a Powermate PM497000 powered by Honda GX390, less than 5 years old.

@Charles: I am familiar with working with electricity but that does not mean I won't get superior help when I need it. Thanks for wanting to keep safe. Goodness knows I need a keeper!

@Darren: How hard can it be to 'read' an oscilloscope? :) Finding qualified electrician is almost an oxymoron around here. Now a redneck electrician can be found without end. Ya know?

Now, off to study isolation transformers.

Keep it coming. Thanks.
 
They aren't cheap, but neither is your lathe and other equipment. Have seen some posts on using an autoformer (http://www.autoformersdirect.com/) in between the generator and electrical devices, may be what you're looking for, but haven't had time to dig into it at all. Looks like they are mostly to boost your signals at the rv park, but work along the lines of a line conditioner.
 
As for the oscilloscope, you may want to check with the local colleges that have EE programs and see if they have an instructor willing to do some testing for you, would be a good use case for their students. That or check with Brent to see if he's caved on buying an oscilloscope yet. :D
 
Grainger had some "power conditioner" products, they arent cheap either, but were also grainger prices. Would be worth getting model numbers from there and shopping around. I also sent our engineers an email, will let you know what they say.

Darren
 
$0.02 worth of info.

Generators once they are running and not near their max load can generate reasonably clean power. It is the starting, stopping, switching loads and engine hiccups that introduce the problems.

Start the generator and get it running smooth prior to turning on the lathe and remember to turn off the lathe before you run out of gas. Also do not let any other large electrical loads start while using the lathe.

To clean up 220V 20 amp with any additional equipment (iso- xformer / line conditioner etc ) will take a lot of $$$
 
Carol, I checked with one of our engineers here at work, below is his response...

Darren,
The RV auto transformer you looked at might not really work for this. She needs to clean up the dirty power of the generator, the autotransformer only adjusts voltage somewhat slowly, not frequency or harmonics. A UPS is designed for this, though it has its own problems with only running from a generator and not having constant utility power, and being very expensive . Assuming her lathe is similar to mine and is less than a 20 amp load at 120 volts, I suggest finding a single circuit surge protector with a built in ups capable of handling only the lathe, much like the ones marketed for home computers. Keep in mind that most generators require a warm up time of usually 5 minutes before use for the governor to even out. I would wait the 5 minutes before switching on the surge protector/UPS and let the UPS charge up before using the lathe. I have had experience with very similar situations with good results. This dirty power from the generator only slightly affects other loads such as incandescent lighting and motors. Only electronics need a clean power source. Good luck.
Matthew
 
Carol, I checked with one of our engineers here at work, below is his response...

Darren,
The RV auto transformer you looked at might not really work for this. She needs to clean up the dirty power of the generator, the autotransformer only adjusts voltage somewhat slowly, not frequency or harmonics. A UPS is designed for this, though it has its own problems with only running from a generator and not having constant utility power, and being very expensive .
<snip>
Matthew

Be aware that there is a wide variation in UPS types and features. What Matthew is talking about is known as a (adequate) "Line-interactive" or (better/more expensive) "Online/double-conversion". The cheaper ones are "Offline/standby". Wikipedia has a decent explanation of the differences: http://en.wikipedia.org/wiki/Uninterruptible_power_supply but in a nutshell the more complicated versions actually pass the power through some internal electronics before handing it back out (the online versions actually pass it through the battery) whereas the (cheaper/consumer quality) Offline/standby versions actually just pass the utility/generator power through and then cut over on utility power loss with no line conditioning at all.

Many of the "single circuit surge protector with a built in ups" are actually the standby versions so just be aware of that..

There is also some variation in power quality between different UPSs, some are "stepped wave" or "square wave" which are less desirable than "true sine wave" (although even those are usually actually a stepped wave but the steps are much smaller). Mostly I'd avoid anything that produces a square wave as it tends to be hard on electronics, almost all modern online UPSs produce a reasonable power signature.
 
Carol, I checked with one of our engineers here at work, below is his response...

Darren,
The RV auto transformer you looked at might not really work for this. She needs to clean up the dirty power of the generator, the autotransformer only adjusts voltage somewhat slowly, not frequency or harmonics. A UPS is designed for this, though it has its own problems with only running from a generator and not having constant utility power, and being very expensive . Assuming her lathe is similar to mine and is less than a 20 amp load at 120 volts, I suggest finding a single circuit surge protector with a built in ups capable of handling only the lathe, much like the ones marketed for home computers. Keep in mind that most generators require a warm up time of usually 5 minutes before use for the governor to even out. I would wait the 5 minutes before switching on the surge protector/UPS and let the UPS charge up before using the lathe. I have had experience with very similar situations with good results. This dirty power from the generator only slightly affects other loads such as incandescent lighting and motors. Only electronics need a clean power source. Good luck.
Matthew

Yup I agree with this engineer. Its all going to be a very expensive proposition. 20 amps is a lot of current period. And generating it and keeping a smooth sine wave while doing it is simply expensive. Same goes for having an inverter and batteries to supply a load like this.

I know most of us independent types don't wish to hear otherwise but maybe you should examine priorities given your circumstances etc and consider how far you go to satisfy certain desires. My lathe is such a cheapie I would love for a generator to "blow it up" and give me a really good excuse to get a new one. But in your case you might want to think its better to downgrade to a smaller unit that requires less fussy power. How much do you really turn and how often. I can hear the spinny cavalry coming down the road to your defense so I will retire my common sense now while I am alive.
 
But in your case you might want to think its better to downgrade to a smaller unit that requires less fussy power. How much do you really turn and how often. I can hear the spinny cavalry coming down the road to your defense so I will retire my common sense now while I am alive.

:rofl: I still think a treadle lathe would be the way to go, think how good a shape you'd be in :D

Then for a bandsaw..: http://www.youtube.com/watch?v=95VsThmszek
 
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