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#1
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220v conversion question
I just had an upgrade for my electric service to a 200 Amp panel as
part of an HVAC upgrade. At the same time, I had the electrician put in 2 220 circuits and 2 120 circuits for my shop (lights were already separate). Last night I switched over my table saw to 220. Wow, start up is almost instant. The question: I plan to switch over my bandsaw to 220 as well. What happens to the gooseneck lamp? The switch over instructions don't mention it. Rewiring for the motor is pretty straightfoward. Am I missing something? |
#2
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220v conversion question
.... I had the electrician put in 2 220 circuits and 2 120 circuits for my shop ...
The question: I plan to switch over my bandsaw to 220 as well. *What happens to the gooseneck lamp? I wired the lamp with one hot line (110v) to the center, and connected a neutral to the outside. ( Sorry - I don't know the precise terminology.) As an alternative, you can find 220v lamps on line. |
#3
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220v conversion question
On Sep 1, 7:05*am, " wrote:
.... I had the electrician put in 2 220 circuits and 2 120 circuits for my shop ... The question: I plan to switch over my bandsaw to 220 as well. *What happens to the gooseneck lamp? I wired the lamp with one hot line (110v) to the center, and connected a neutral to the outside. ( Sorry - I don't know the precise terminology.) In most 240 circuits there is no neutral (certainly not those used for tools). Wiring it to ground isn't a good idea either. As an alternative, you can find 220v lamps on line. A much better idea. |
#4
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220v conversion question
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#5
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220v conversion question
On Sep 1, 9:38*am, dpb wrote:
wrote: ... In most 240 circuits there is no neutral (certainly not those used for tools). *Wiring it to ground isn't a good idea either. Well, split-voltage appliances (ranges, dryers, ...) have run that way for approaching 100 years w/o any significant issues. They don't anymore, and for a reason. Only w/ a relatively late NEC revision did the requirement for 4-wire service come into play. For a reason. While it strictly speaking, isn't up to current Code, for a load no larger than the work lamp there's no issue imo. Your opinion isn't going to matter if someone gets hurt. It's a lot easier to wire a separate circuit. This came up not too long ago and someone noted that between an early manual and later the particular manufacturer of his dp had dropped the illustration/wiring diagram for the split voltage, undoubtedly to maintain strict Code compliance from a liability standpoint. *However, they hadn't changed the wiring iiuc... Their lawyers are dumber than stumps if they think paperwork is going to get them out of the inevitable lawsuit. Do they have a compliance (UL, etc.) mark on them? As an alternative, you can find 220v lamps on line. A much better idea. Take your choice; I'd just rewire it meself... You're perfectly within your rights to knowingly violate codes. No "grandfather" excuse here, either. |
#6
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220v conversion question
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#7
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220v conversion question
Another alternative is to add a second lamp of identical wattage
and wire them in series. -- There is always an easy solution to every human problem -- neat, plausible, and wrong." (H L Mencken) Larry Wasserman - Baltimore Maryland - lwasserm(a)sdf. lonestar. org |
#8
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220v conversion question
On Tue, 1 Sep 2009 10:58:01 -0700 (PDT), "
wrote: This came up not too long ago and someone noted that between an early manual and later the particular manufacturer of his dp had dropped the illustration/wiring diagram for the split voltage, undoubtedly to maintain strict Code compliance from a liability standpoint. *However, they hadn't changed the wiring iiuc... Their lawyers are dumber than stumps if they think paperwork is going to get them out of the inevitable lawsuit. Do they have a compliance (UL, etc.) mark on them? I'm not sure if "dpb" was referring to me, or not, but I found that with my DP. Motor can be rewired for 240, but the wiring harness has no provisions for a neutral feed. The "stock" harness connects the work lamp across the two non-ground leads so that if the DP is plugged into a 120v circuit, the lamp socket sees 120. And if plugged into a 240v circuit, the socket sees 240v. I'd strongly suspect the OP's band saw is similar. He'll certainly find out if he rewires the motor for 240 and his work light (with a 120v bulb) burns very brightly for a very short time. Several years ago, on the manufacturer's web site, the PDF manual for the DP, as a part of the diagram for rewiring the tool for 240, showed the work light socket being changed to connect across one hot lead and the EGC to provide 120 to the lamp. I went back to the site at a later date, and that part of the diagram was no longer there. It now shows only a configuration that connects the lamp socket across the non-ground leads with no direct connection to the EGC. I suspect the diagram was deleted as a result of UL requirements. Using the EGC for an operational conductor does violate the current NEC. But, the NEC doesn't cover anything beyond the wall plug. It's only applicable to permanent wiring, so rewiring the DP (or band saw) to supply 120v from a 2+G 240 circuit doesn't technically violate the NEC unless the device is hardwired into the facility wiring. That doesn't mean it's any more or less safe, just that it's not covered by the NEC. That's according to my understanding of the scope of the NEC. Even if "plug in" loads was covered by the NEC, compliance would be impossible to enforce unless you had to pull a permit and get an inspector out every time you plugged the vacuum cleaner into the living room wall socket. Using the tool's EGC for a neutral return will, as stated, energize the grounded portions of everything connected to that circuit, as well as everything on every circuit which has an EGC connected to the ground bus in the panel that houses that circuit. The voltage on those energized grounds will be the product of the resistance to ground of the panel's ground bus times the current flowing from the ground bus to ground. May or may not be dangerous depending on the amperage and the resistance to ground. Incidentally that is the same condition that exists if any device drawing current through that panel develops a short to ground. Until the breaker trips (assuming the leakage to ground is enough to trip the breaker) every grounded item in, or connected to, that panel will be energized with that amps x resistance voltage. The use of GFI breakers addresses that condition by tripping anytime there is a very small difference in the amperage in the two non-EGC conductors. Otherwise the fault current would have to be on the order of the breaker rating. A DP or BS rewired to use the EGC as neutral on a 240v circuit would certainly trip any 240v GFI breaker that monitored the current in the two hot wires the way a 120v GFI breaker monitors the current in the hot and neutral wires. Tom Veatch Wichita, KS USA |
#9
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220v conversion question
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#10
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220v conversion question
"Dave - Parkville, MD" wrote in message ... I just had an upgrade for my electric service to a 200 Amp panel as part of an HVAC upgrade. At the same time, I had the electrician put in 2 220 circuits and 2 120 circuits for my shop (lights were already separate). Last night I switched over my table saw to 220. Wow, start up is almost instant. The question: I plan to switch over my bandsaw to 220 as well. What happens to the gooseneck lamp? The switch over instructions don't mention it. Rewiring for the motor is pretty straightfoward. Am I missing something? I am no electrical expert but iIwould guess it will work OK. If you have normal residental home wiring you will actually have 2- 110 volt lines going to your BS. Add them up and you get 220 volts. The lamp will probably continue to have 1 single 110 volt line going to it. Electric ovens and ranges have the same set up. |
#11
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220v conversion question
"Leon" wrote in message news "Dave - Parkville, MD" wrote in message ... I just had an upgrade for my electric service to a 200 Amp panel as part of an HVAC upgrade. At the same time, I had the electrician put in 2 220 circuits and 2 120 circuits for my shop (lights were already separate). Last night I switched over my table saw to 220. Wow, start up is almost instant. The question: I plan to switch over my bandsaw to 220 as well. What happens to the gooseneck lamp? The switch over instructions don't mention it. Rewiring for the motor is pretty straightfoward. Am I missing something? I am no electrical expert but iIwould guess it will work OK. If you have normal residental home wiring you will actually have 2- 110 volt lines going to your BS. Add them up and you get 220 volts. The lamp will probably continue to have 1 single 110 volt line going to it. Electric ovens and ranges have the same set up. What he said. I'm in Baltimore and on the same lines as you, Dave. Ed |
#12
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220v conversion question
On Sep 1, 9:11*am, "Leon" wrote:
"Dave - Parkville, MD" wrote in ... I just had an upgrade for my electric service to a 200 Amp panel as part of an HVAC upgrade. *At the same time, I had the electrician put in 2 220 circuits and 2 120 circuits for my shop (lights were already separate). *Last night I switched over my table saw to 220. *Wow, start up is almost instant. The question: I plan to switch over my bandsaw to 220 as well. *What happens to the gooseneck lamp? *The switch over instructions don't mention it. *Rewiring for the motor is pretty straightfoward. *Am I missing something? I am no electrical *expert but iIwould guess it will work OK. *If you have normal residental home wiring you will actually have 2- 110 volt lines going to your BS. *Add them up and you get 220 volts. *The lamp will probably continue to have 1 single 110 volt line going to it. Electric ovens and ranges have the same set up. Good point Leon. I know in a 4 wire 220 supply you can have two hots, a neutral and a ground. The outlet and plug will only have a 3 wires (2 hots and ground). I haven't pulled the plate off of the motor yet, maybe there is more info there. I am a bit shocked (no pun) that Powermatic's site doesn't have much support. |
#13
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220v conversion question
On Sep 1, 8:11*am, "Leon" wrote:
"Dave - Parkville, MD" wrote in ... I just had an upgrade for my electric service to a 200 Amp panel as part of an HVAC upgrade. *At the same time, I had the electrician put in 2 220 circuits and 2 120 circuits for my shop (lights were already separate). *Last night I switched over my table saw to 220. *Wow, start up is almost instant. The question: I plan to switch over my bandsaw to 220 as well. *What happens to the gooseneck lamp? *The switch over instructions don't mention it. *Rewiring for the motor is pretty straightfoward. *Am I missing something? I am no electrical *expert but iIwould guess it will work OK. *If you have normal residental home wiring you will actually have 2- 110 volt lines going to your BS. *Add them up and you get 220 volts. *The lamp will probably continue to have 1 single 110 volt line going to it. It'll work but it's against code and (somewhat) unsafe. To split off 120V you need a neutral. Electric ovens and ranges have the same set up. Electric ovens have a neutral, or at least they do now. |
#14
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220v conversion question
wrote in message ... On Sep 1, 8:11 am, "Leon" wrote: "Dave - Parkville, MD" wrote in ... OK. If you have normal residental home wiring you will actually have 2- 110 volt lines going to your BS. Add them up and you get 220 volts. The lamp will probably continue to have 1 single 110 volt line going to it. It'll work but it's against code and (somewhat) unsafe. To split off 120V you need a neutral. Electric ovens and ranges have the same set up. Electric ovens have a neutral, or at least they do now. Correct, I was just trying to point out a logical picutre. Absolutely they have neutral lines. |
#16
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220v conversion question
In article , Jack Stein wrote:
wrote: I am no electrical expert but iIwould guess it will work OK. If you have normal residental home wiring you will actually have 2- 110 volt lines going to your BS. Add them up and you get 220 volts. The lamp will probably continue to have 1 single 110 volt line going to it. It'll work but it's against code and (somewhat) unsafe. To split off 120V you need a neutral. Just out of dumb curiosity, does this mean if you don't split off 120, you don't need a neutral? Exactly so. Pure 240V circuits (in North America) don't have, or need, a neutral. Normally, with 120 you need 2 wires plus ground, hot, common and ground. I don't know zip about 220 but are you guys saying 220 can have 2 wires, both hot, plus a ground (no common), Yes. and you connect one of the hots to the light, and what normally would be common or neutral to the ground? No. It will work, but it's unsafe, and violates both the U.S. and Canadian electrical codes. I'm in the dark here, just asking. Doesn't 220 always need a common ground (neutral?), just like 120? It's 240, not 220. And no, it doesn't need a neutral. 120 needs a neutral; so, if an appliance has both 240V and 120V loads (e.g. electric stove: 240V heating elements, 120V control circuits; electric dryer: 240V heating elements, 120V motor) then it needs a four wires: two hots, neutral (for the 120V) and equipment (safety) ground. Pure 240V loads (e.g. a table saw or welder) need only three: two hots and equipment ground. No neutral. |
#17
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220v conversion question
Doug Miller wrote:
Jack Stein wrote: Just out of dumb curiosity, does this mean if you don't split off 120, you don't need a neutral? Exactly so. Pure 240V circuits (in North America) don't have, or need, a neutral. Doug, thanks for your clear reply. I use the same coloring book Leon uses when it comes to electricity so any enlightenment is welcome. I know enough to wire 120 circuits in my sleep, without killing me, or anyone else so far, but Normally, with 120 you need 2 wires plus ground, hot, common and ground. I don't know zip about 220 but are you guys saying 220 can have 2 wires, both hot, plus a ground (no common), Yes. OK, but in my 120 coloring book, electricity comes in the hot wire, and goes out the neutral wire, thus the circuit, or loop is completed. How does this work with 220? and you connect one of the hots to the light, and what normally would be common or neutral to the ground? No. It will work, but it's unsafe, and violates both the U.S. and Canadian electrical codes. It sounds unsafe to me to be connecting a common ground to the safety ground. In my small world, most of the time the safety ground is a bare copper wire, not even insulated. In a 120 circuit, it would seem anytime the load is hot, the common wire is carrying current back to ground? Also, the motor frame, electrical box etc is connected to the safety ground, would this mean the box/motor frame is hot whenever the the load is on if you used the safety ground as a neutral wire? In Somona's instance, he has his 240 motor hooked up, plus he has a 120 motor running the feed rollers. Assuming a 3 wire 240 hookup, he could (unsafely, but common in the past?) hook one hot wire to the 120 motor, and use the safety ground as the neutral wire for the 120 motor. If he did this, the safety ground would always be carrying juice when the motor was running, and ergo, anything hooked up to the safety ground, the motor frame, wiring boxes and so on, would also be carrying juice? Is that correct? If so, it sure sounds too dangerous to have been done routinely for 100 years? I'm sure I'm missing something here, but hey, I'm just trying to color in some of the pages:-) I'm in the dark here, just asking. Doesn't 220 always need a common ground (neutral?), just like 120? It's 240, not 220. I'm glad you said that. I was thinking damn, I don't even know if my service is 110, 115 or 120? I see all sorts of things on electrical devices. Even this thread is stating 220, or 2 110 lines? You are the only one to correct it so far. No wonder I'm so confused... still alive though:-) And no, it doesn't need a neutral. 120 needs a neutral; Again, this confuses me. How is the circuit completed in a 240 circuit? 2 120 lines come from the source to the motor, then what? Where does it go? I bet it has something to do with phase? Each line takes turns being the neutral? If not, I'm lost, if so, still lost:-) -- Jack Using FREE News Server: http://www.eternal-september.org/ http://jbstein.com |
#18
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220v conversion question
On Sep 1, 11:03*am, Jack Stein wrote:
wrote: It'll work but it's against code and (somewhat) unsafe. *To split off 120V you need a neutral. Just out of dumb curiosity, does this mean if you don't split off 120, you don't need a neutral? 220V wired to a three pole socket has HOT1, HOT2, and ground. Wired to a four-pole socket, it has HOT1, neutral, HOT2, and ground. While generally considered poor practice, it was normal for many years in the US for stoves and clothes dryers to have a heavy three-prong plug for 220V 30A, and a small (fused 10A) auxiliary 110V circuit that ran from one hot wire to ground. Safety code had an "appliance exception" for this, and it was done because a 4-wire 30A circuit and socket would have been excessive and expensive. Think about it: there's gotta be a 30A ground wire for these items, and it carries NO current; to add a 120V 10A convenience socket, do you want to add a 30A neutral wire as well? |
#19
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220v conversion question
On Sep 1, 1:03*pm, Jack Stein wrote:
wrote: I am no electrical *expert but iIwould guess it will work OK. *If you have normal residental home wiring you will actually have 2- 110 volt lines going to your BS. *Add them up and you get 220 volts. *The lamp will probably continue to have 1 single 110 volt line going to it. It'll work but it's against code and (somewhat) unsafe. *To split off 120V you need a neutral. Just out of dumb curiosity, does this mean if you don't split off 120, you don't need a neutral? *Normally, with 120 you need 2 wires plus ground, hot, common and ground. *I don't know zip about 220 but are you guys saying 220 can have 2 wires, both hot, plus a ground (no common), and you connect one of the hots to the light, and what normally would be common or neutral to the ground? * You generally need a ground but only need the neutral if you are using the split phase (the 120V part). So, 240V will usually have three wires (if there aren't any 120V loads) or four (with 120V loads). I'm in the dark here, just asking. Doesn't 220 always need a common ground (neutral?), just like 120? Be careful, "ground" and "neutral" are different things. "Ground" is used for safety purposes only. "Neutral" is a current carrying conductor. If there is no current in the neutral (as is the case in a purely 240V circuit) there isn't any need for the conductor. ;-) |
#20
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220v conversion question
Jack Stein wrote:
.... Just out of dumb curiosity, does this mean if you don't split off 120, you don't need a neutral? Normally, with 120 you need 2 wires plus ground, hot, common and ground. I don't know zip about 220 but are you guys saying 220 can have 2 wires, both hot, plus a ground (no common), and you connect one of the hots to the light, and what normally would be common or neutral to the ground? I'm in the dark here, just asking. Doesn't 220 always need a common ground (neutral?), just like 120? By NEC it now does to be Code-compliant. For roughly 100 years, split-voltage appliances such as ranges, dryers, etc., used (and were Code-compliant!!!!) the ground as neutral for the 110V side. Only w/ a relatively recent Code revision was this changed to require the 4-wire connection in all cases. While granted it's not current Code, there are zillions of appliances still in service and certainly a fair number of drill presses and other machine tools wired the same way. There's absolutely no evidence they have been a major safety issue in that time period. Hence, while granted it's no longer within _current_ Code, there's little real justification for that change being a big deal. $0.02, etc., etc., ... -- |
#21
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220v conversion question
In article , dpb wrote:
Jack Stein wrote: .... Just out of dumb curiosity, does this mean if you don't split off 120, you don't need a neutral? Normally, with 120 you need 2 wires plus ground, hot, common and ground. I don't know zip about 220 but are you guys saying 220 can have 2 wires, both hot, plus a ground (no common), and you connect one of the hots to the light, and what normally would be common or neutral to the ground? I'm in the dark here, just asking. Doesn't 220 always need a common ground (neutral?), just like 120? By NEC it now does to be Code-compliant. That is incorrect. Pure 240V circuits do *not* need a neutral conductor. For roughly 100 years, split-voltage appliances such as ranges, dryers, etc., used (and were Code-compliant!!!!) the ground as neutral for the 110V side. Only w/ a relatively recent Code revision was this changed to require the 4-wire connection in all cases. No, only in those cases where the circuit supplies both 240V and 120V loads. |
#22
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220v conversion question
On Tue, 01 Sep 2009 13:03:42 -0500, Jack Stein
wrote: Doesn't 220 always need a common ground (neutral?), just like 120? No. Speaking in the context of "normal" residential, single phase 120v/240v service, circuits that supply only 240v do not need or use the neutral. Only the 120v circuits use the neutral wire. Multiwire circuits that supply both 240 and 120 do need the neutral to support the 120v loads. Tom Veatch Wichita, KS USA |
#23
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220v conversion question
On 09/01/2009 05:25 AM, Dave - Parkville, MD wrote:
I just had an upgrade for my electric service to a 200 Amp panel as part of an HVAC upgrade. At the same time, I had the electrician put in 2 220 circuits and 2 120 circuits for my shop (lights were already separate). Last night I switched over my table saw to 220. Wow, start up is almost instant. If it makes that much difference, there was probably something wrong with the 120V circuit or wire size. If everything was sized properly there shouldn't really be any difference. The question: I plan to switch over my bandsaw to 220 as well. What happens to the gooseneck lamp? The switch over instructions don't mention it. Rewiring for the motor is pretty straightfoward. Am I missing something? My bandsaw has a separate plug for the lamp. If it's not mentioned they're probably using the safety ground as a neutral which you're not really supposed to do. Chris |
#24
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220v conversion question
In article , Chris Friesen wrote:
On 09/01/2009 05:25 AM, Dave - Parkville, MD wrote: I just had an upgrade for my electric service to a 200 Amp panel as part of an HVAC upgrade. At the same time, I had the electrician put in 2 220 circuits and 2 120 circuits for my shop (lights were already separate). Last night I switched over my table saw to 220. Wow, start up is almost instant. If it makes that much difference, there was probably something wrong with the 120V circuit or wire size. If everything was sized properly there shouldn't really be any difference. Sorry, but that's not correct. At 240V, it will draw half the current that it did at 120V. This will provide a much faster start, even if the 120V circuit was properly sized. The question: I plan to switch over my bandsaw to 220 as well. What happens to the gooseneck lamp? The switch over instructions don't mention it. Rewiring for the motor is pretty straightfoward. Am I missing something? My bandsaw has a separate plug for the lamp. If it's not mentioned they're probably using the safety ground as a neutral which you're not really supposed to do. More than "not supposed to do". It's unsafe, because it energizes the ground conductor, thus energizing the chassis of *everything* that's plugged into that circuit. Remember that electricity does not "follow the path of least resistance" as many people believe; rather, it follows all possible paths. That includes the path that goes through the grounding conductor to the chassis of the saw to the saw table to the hands of the operator. |
#25
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220v conversion question
On 09/01/2009 08:35 AM, Doug Miller wrote:
In article , Chris Friesen wrote: On 09/01/2009 05:25 AM, Dave - Parkville, MD wrote: I just had an upgrade for my electric service to a 200 Amp panel as part of an HVAC upgrade. At the same time, I had the electrician put in 2 220 circuits and 2 120 circuits for my shop (lights were already separate). Last night I switched over my table saw to 220. Wow, start up is almost instant. If it makes that much difference, there was probably something wrong with the 120V circuit or wire size. If everything was sized properly there shouldn't really be any difference. Sorry, but that's not correct. At 240V, it will draw half the current that it did at 120V. This will provide a much faster start, even if the 120V circuit was properly sized. I agree it will draw half the current. Assuming properly sized conductors such that voltage loss is negligible, why would 6A at 240V behave any differently than 12A at 120V? In both cases we're drawing 1440W. Now it's possible that the motor itself could be designed such that it runs more efficiently at 240V than at 120V. This isn't necessarily the case here, but if it is it would be due to the motor design, not the higher voltage as such. The question: I plan to switch over my bandsaw to 220 as well. What happens to the gooseneck lamp? The switch over instructions don't mention it. Rewiring for the motor is pretty straightfoward. Am I missing something? My bandsaw has a separate plug for the lamp. If it's not mentioned they're probably using the safety ground as a neutral which you're not really supposed to do. More than "not supposed to do". It's unsafe, because it energizes the ground conductor, thus energizing the chassis of *everything* that's plugged into that circuit. Remember that electricity does not "follow the path of least resistance" as many people believe; rather, it follows all possible paths. That includes the path that goes through the grounding conductor to the chassis of the saw to the saw table to the hands of the operator. It's true that electricity will follow all possible paths, but the higher the resistance of a particular path relative to the other paths the less electricity will flow through it. The safety ground is a low-resistance path, so most of the electricity will flow through it rather than through the operator. Older electric dryers and kitchen ranges using 3-pin plugs generally run their control circuitry and lights at 120V using the safety ground as a neutral. Not ideal, but it's not unusual either. Chris |
#26
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220v conversion question
In article , Chris Friesen wrote:
On 09/01/2009 08:35 AM, Doug Miller wrote: In article , Chris Friesen wrote: On 09/01/2009 05:25 AM, Dave - Parkville, MD wrote: I just had an upgrade for my electric service to a 200 Amp panel as part of an HVAC upgrade. At the same time, I had the electrician put in 2 220 circuits and 2 120 circuits for my shop (lights were already separate). Last night I switched over my table saw to 220. Wow, start up is almost instant. If it makes that much difference, there was probably something wrong with the 120V circuit or wire size. If everything was sized properly there shouldn't really be any difference. Sorry, but that's not correct. At 240V, it will draw half the current that it did at 120V. This will provide a much faster start, even if the 120V circuit was properly sized. I agree it will draw half the current. Assuming properly sized conductors such that voltage loss is negligible, why would 6A at 240V behave any differently than 12A at 120V? In both cases we're drawing 1440W. Higher voltage. Now it's possible that the motor itself could be designed such that it runs more efficiently at 240V than at 120V. This isn't necessarily the case here, but if it is it would be due to the motor design, not the higher voltage as such. The question: I plan to switch over my bandsaw to 220 as well. What happens to the gooseneck lamp? The switch over instructions don't mention it. Rewiring for the motor is pretty straightfoward. Am I missing something? My bandsaw has a separate plug for the lamp. If it's not mentioned they're probably using the safety ground as a neutral which you're not really supposed to do. More than "not supposed to do". It's unsafe, because it energizes the ground conductor, thus energizing the chassis of *everything* that's plugged into that circuit. Remember that electricity does not "follow the path of least resistance" as many people believe; rather, it follows all possible paths. That includes the path that goes through the grounding conductor to the chassis of the saw to the saw table to the hands of the operator. It's true that electricity will follow all possible paths, but the higher the resistance of a particular path relative to the other paths the less electricity will flow through it. The safety ground is a low-resistance path, so most of the electricity will flow through it rather than through the operator. Quite true; OTOH, at 120VAC 60Hz, it takes only a few tens of milliamperes to interfere with heart rhythms, thus *any* current flowing through the operator is a potential hazard. |
#27
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220v conversion question
On 09/01/2009 11:08 AM, Doug Miller wrote:
In article , Chris Friesen wrote: I agree it will draw half the current. Assuming properly sized conductors such that voltage loss is negligible, why would 6A at 240V behave any differently than 12A at 120V? In both cases we're drawing 1440W. Higher voltage. Huh? Voltage is just potential. You need power to do work, and the amount of power (and thus the amount of work that can be done) is the same in each case. Faster startup implies that the mechanical work of spinning up the motor is done in a shorter amount of time. This means either the motor is more efficient at 240V or else it's drawing more power. In both cases this would be due to motor design, not simply higher voltage. Chris |
#28
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220v conversion question
On Tue, 01 Sep 2009 10:48:17 -0600, Chris Friesen
wrote: Now it's possible that the motor itself could be designed such that it runs more efficiently at 240V than at 120V. This isn't necessarily the case here, but if it is it would be due to the motor design, not the higher voltage as such. Not likely. Typical dual voltage motors are set up such that two windings are in series for 240v and in parallel for 120v. So regardless of the supplied voltage, the voltage drop and current in each of the windings is the same in either case. In other words, the working parts of the motor don't know the difference between the motor being connected to 240v or 120v. Tom Veatch Wichita, KS USA |
#29
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220v conversion question
Doug Miller wrote:
Sorry, but that's not correct. At 240V, it will draw half the current that it did at 120V. This will provide a much faster start, even if the 120V circuit was properly sized. Woah up a second here! That's true if the device is built to run off of 240 Volts. But if the internal resistance is the same as it was in the 120 device, it will draw TWICE the amperage - until it "opens". |
#30
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220v conversion question
In article , cavelamb wrote:
Doug Miller wrote: Sorry, but that's not correct. At 240V, it will draw half the current that it did at 120V. This will provide a much faster start, even if the 120V circuit was properly sized. Woah up a second here! That's true if the device is built to run off of 240 Volts. But if the internal resistance is the same as it was in the 120 device, it will draw TWICE the amperage - until it "opens". I was under the impression we were talking about reconfiguring a dual-voltage 120/240 motor from 120 to 240. I don't think anybody was suggesting operating a 120V motor at 240V. |
#31
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220v conversion question
I was under the impression we were talking about reconfiguring a dual-voltage 120/240 motor from 120 to 240. I don't think anybody was suggesting operating a 120V motor at 240V. Dual voltage motor - correct. |
#32
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220v conversion question
Slightly OT but relevant.
I am a no nothing in terms of electrical. I can properly wire a plug or wall sockets but don't understand the flow, grounding, etc. Just never studied it. But on a related topic, I have always wondered why my planer and my big sander have a 220 line to run the big moter and a 110 line to run the feed table. I asked on of the Mfg's if there was a way to wire the 110 from the 220 and they clearly ran and hide, saying don't ask us. So I ask here. Is there some way to "properly" do this? Can I put an onboard converter or something. I would really like to eliminate the two cords scenario because I am constantly juggling machines because of my space restrictions and it is a big hassle with two plugs. On Sep 1, 6:56*am, Chris Friesen wrote: On 09/01/2009 05:25 AM, Dave - Parkville, MD wrote: I just had an upgrade for my electric service to a 200 Amp panel as part of an HVAC upgrade. *At the same time, I had the electrician put in 2 220 circuits and 2 120 circuits for my shop (lights were already separate). *Last night I switched over my table saw to 220. *Wow, start up is almost instant. If it makes that much difference, there was probably something wrong with the 120V circuit or wire size. *If everything was sized properly there shouldn't really be any difference. The question: I plan to switch over my bandsaw to 220 as well. *What happens to the gooseneck lamp? *The switch over instructions don't mention it. *Rewiring for the motor is pretty straightfoward. *Am I missing something? My bandsaw has a separate plug for the lamp. *If it's not mentioned they're probably using the safety ground as a neutral which you're not really supposed to do. Chris |
#33
Posted to rec.woodworking
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220v conversion question
On 09/01/2009 11:55 AM, SonomaProducts.com wrote:
Slightly OT but relevant. I am a no nothing in terms of electrical. I can properly wire a plug or wall sockets but don't understand the flow, grounding, etc. Just never studied it. But on a related topic, I have always wondered why my planer and my big sander have a 220 line to run the big moter and a 110 line to run the feed table. I asked on of the Mfg's if there was a way to wire the 110 from the 220 and they clearly ran and hide, saying don't ask us. So I ask here. Is there some way to "properly" do this? Can I put an onboard converter or something. I would really like to eliminate the two cords scenario because I am constantly juggling machines because of my space restrictions and it is a big hassle with two plugs. Sure, but it might not be worth the hassle. To do it properly you'd need a 3-conductor plus ground cable, with a 4-prong plug. Two hots, neutral, and ground. Bring the main cord into a junction box mounted to the tool somewhere. In the junction box split the wires out appropriately to the two motors. The main motor then gets driven by the two hots, while the feed table gets driven by a hot and the neutral. The ampacity of the conductors must be suffient to provide for both the feed table and the main motor, so you'd probably have to increase the conductor size. You'll likely need to add a special 4-prong receptacle, also wired with large enough conductors. It's probably easier to just zip-tie the two cords together so that they don't get tangled. Chris |
#34
Posted to rec.woodworking
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220v conversion question
SonomaProducts.com wrote:
Slightly OT but relevant. I am a no nothing in terms of electrical. I can properly wire a plug or wall sockets but don't understand the flow, grounding, etc. Just never studied it. But on a related topic, I have always wondered why my planer and my big sander have a 220 line to run the big moter and a 110 line to run the feed table. I asked on of the Mfg's if there was a way to wire the 110 from the 220 and they clearly ran and hide, saying don't ask us. So I ask here. Is there some way to "properly" do this? Can I put an onboard converter or something. I would really like to eliminate the two cords scenario because I am constantly juggling machines because of my space restrictions and it is a big hassle with two plugs. .... They say "don't ask us" because of the the revised NEC Code requirements discussed in the upthread subthread sidebar discussion. In all likelihood previously they would have simply used the three-wire appliance-style arrangement and all would have been happy; now they can't do that and as Chris explains the hassle of the four-wire connections they result was they probably decided simply the two-cord solution was the easiest for them and still meet current Code. As for what to do; depends in large part on whether you're in a situation where your shop does have to be current-Code-compliant or this is a personal shop. I gather your situation is probably the former so you probably don't want to take the expedient way out and so the only real choice is probably to either live with it as is or rewire to the four-conductor supply. How much of a pain and what you would have to do physically is dependent on the shop wiring extant now as well as the sizes of the various motors involved. In short, as Chris says, you can but it may not be worth the hassles despite the other existing hassle. -- |
#35
Posted to rec.woodworking
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220v conversion question
In article , "SonomaProducts.com" wrote:
Slightly OT but relevant. I am a no nothing in terms of electrical. I can properly wire a plug or wall sockets but don't understand the flow, grounding, etc. Just never studied it. But on a related topic, I have always wondered why my planer and my big sander have a 220 line to run the big moter and a 110 line to run the feed table. I asked on of the Mfg's if there was a way to wire the 110 from the 220 and they clearly ran and hide, saying don't ask us. So I ask here. Is there some way to "properly" do this? Can I put an onboard converter or something. I would really like to eliminate the two cords scenario because I am constantly juggling machines because of my space restrictions and it is a big hassle with two plugs. Yes, there is. How easy it will be depends on whether the 240V circuit (not "220") supplying the machine has a neutral or not. If not, you'll need a new circuit. Assuming that you have a four-wire 240V circuit available (two hot legs, neutral, and ground), install a 4-conductor receptacle on that circuit, and a 4-conductor plug and cord on the machine. Connect the planer motor to the two hot wires; connect the feed-table motor to one of the hot wires (it doesn't matter which one) and the neutral wire. Connect the ground wire to the frame of the unit. |
#36
Posted to rec.woodworking
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220v conversion question
Thanks guys. This is my home shop but I don't want to do the 4 wire
work so I guess I'll live with it. It just seems kind of silly. Maybe I can find some 220 fractional hp motors to run my feed tables. On Sep 1, 10:55*am, "SonomaProducts.com" wrote: Slightly OT but relevant. I am a no nothing in terms of electrical. I can properly wire a plug or wall sockets but don't understand the flow, grounding, etc. Just never studied it. But on a related topic, I have always wondered why my planer and my big sander have a 220 line to run the big moter and a 110 line to run the feed table. I asked on of the Mfg's if there was a way to wire the 110 from the 220 and they clearly ran and hide, saying don't ask us. So I ask here. Is there some way to "properly" do this? Can I put an onboard converter or something. I would really like to eliminate the two cords scenario because I am constantly juggling machines because of my space restrictions and it is a big hassle with two plugs. On Sep 1, 6:56*am, Chris Friesen wrote: On 09/01/2009 05:25 AM, Dave - Parkville, MD wrote: I just had an upgrade for my electric service to a 200 Amp panel as part of an HVAC upgrade. *At the same time, I had the electrician put in 2 220 circuits and 2 120 circuits for my shop (lights were already separate). *Last night I switched over my table saw to 220. *Wow, start up is almost instant. If it makes that much difference, there was probably something wrong with the 120V circuit or wire size. *If everything was sized properly there shouldn't really be any difference. The question: I plan to switch over my bandsaw to 220 as well. *What happens to the gooseneck lamp? *The switch over instructions don't mention it. *Rewiring for the motor is pretty straightfoward. *Am I missing something? My bandsaw has a separate plug for the lamp. *If it's not mentioned they're probably using the safety ground as a neutral which you're not really supposed to do. Chris- Hide quoted text - - Show quoted text - |
#37
Posted to rec.woodworking
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220v conversion question
SonomaProducts.com wrote:
Thanks guys. This is my home shop but I don't want to do the 4 wire work so I guess I'll live with it. It just seems kind of silly. Maybe I can find some 220 fractional hp motors to run my feed tables. .... How large _are_ the 110 loads? To keep the one particular individual off my back note I'm _NOT_ telling you to do this but there still _is_ the unmentionable solution... -- |
#38
Posted to rec.woodworking
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220v conversion question
I really don't even understand electrical concepts to know how to
determine what the load would be. If I can string a few wires together to get juice where I need it I am capable but only venture into such issues when there is no question of how to proceed. Swapping out a switch, changing a plug to match a socket, etc. No worries, just a curiosity for now. Would like a better solution but the best solution is to get a bigger shop and be able to leave machines in place, pulg in once and forget. On Sep 1, 7:21*pm, dpb wrote: SonomaProducts.com wrote: Thanks guys. This is my home shop but I don't want to do the 4 wire work so I guess I'll live with it. It just seems kind of silly. Maybe I can find some 220 fractional hp motors to run my feed tables. ... How large _are_ the 110 loads? *To keep the one particular individual off my back note I'm _NOT_ telling you to do this but there still _is_ the unmentionable solution... -- |
#39
Posted to rec.woodworking
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220v conversion question
On Sep 1, 10:55*am, "SonomaProducts.com" wrote:
Slightly OT but relevant. .... I asked on of the Mfg's if there was a way to wire the 110 from the 220 and they clearly ran and hide, saying don't ask us. So I ask here. Is there some way to "properly" do this? Two ways. First, you can use a 220/110V transformer (do the voltage conversion the hard way). Second, you can note that the motor may have series-connected windings for 220V, one of the motor internal wiring taps has 110V on it when the motor is operating. That means your light goes off when the motor is switched off, of course... My preference would be to use a 12V halogen worklight, and get the 220 to 12V version of transformer for it. The 12V lamps are more vibration-resistant, and you have to have the transformer anyhow (no real difference in cost, though some suppliers might not price it that way). |
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