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Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work. |
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#41
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On Sat, 26 May 2018 19:58:13 -0400, Neon John wrote:
On Fri, 25 May 2018 11:31:59 -0500, Terry Coombs wrote: * I think you'll find that those 3 pins are neutral and 220 on the other 2 , with either hot to the neutral at 110 . The 3 conductor 240 volt cable is 2 hots and ground. No neutral and thus no 120 volts. Mine has a 4 wire socket , with 2 hots a neutral and a ground . That's what it takes to have a neutral and a safety ground. I think the NEC demands those only in hospitals. Everyone else has 2 hots and a not. (safety ground w/ no current) -- If we can ever make red tape nutritional, we can feed the world. --Robert Schaeberle |
#42
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Posted to rec.crafts.metalworking
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On Sun, 27 May 2018 22:24:04 -0700, Larry Jaques
wrote: On Sat, 26 May 2018 19:58:13 -0400, Neon John wrote: On Fri, 25 May 2018 11:31:59 -0500, Terry Coombs wrote: * I think you'll find that those 3 pins are neutral and 220 on the other 2 , with either hot to the neutral at 110 . The 3 conductor 240 volt cable is 2 hots and ground. No neutral and thus no 120 volts. Mine has a 4 wire socket , with 2 hots a neutral and a ground . That's what it takes to have a neutral and a safety ground. I think the NEC demands those only in hospitals. Everyone else has 2 hots and a not. (safety ground w/ no current) Required for ranges and driers for at least the last 10 years here in Canada - don't know abiout the backwaters of the USA |
#43
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Posted to rec.crafts.metalworking
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On Mon, 28 May 2018 11:28:19 -0400, Clare Snyder
wrote: On Sun, 27 May 2018 22:24:04 -0700, Larry Jaques wrote: On Sat, 26 May 2018 19:58:13 -0400, Neon John wrote: On Fri, 25 May 2018 11:31:59 -0500, Terry Coombs wrote: * I think you'll find that those 3 pins are neutral and 220 on the other 2 , with either hot to the neutral at 110 . The 3 conductor 240 volt cable is 2 hots and ground. No neutral and thus no 120 volts. Mine has a 4 wire socket , with 2 hots a neutral and a ground . That's what it takes to have a neutral and a safety ground. I think the NEC demands those only in hospitals. Everyone else has 2 hots and a not. (safety ground w/ no current) Required for ranges and driers for at least the last 10 years here in Canada - don't know abiout the backwaters of the USA New construction/retrofits must have that safety ground and the neutral, bonded inside the breaker box. Some locales are stricter than others about what a "retrofit" is. Most...most "backwaters" have it on the books..but really dont care. as long as its safe. --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus |
#44
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Posted to rec.crafts.metalworking
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On Mon, 28 May 2018 11:28:19 -0400, Clare Snyder
wrote: On Sun, 27 May 2018 22:24:04 -0700, Larry Jaques wrote: On Sat, 26 May 2018 19:58:13 -0400, Neon John wrote: On Fri, 25 May 2018 11:31:59 -0500, Terry Coombs wrote: * I think you'll find that those 3 pins are neutral and 220 on the other 2 , with either hot to the neutral at 110 . The 3 conductor 240 volt cable is 2 hots and ground. No neutral and thus no 120 volts. Mine has a 4 wire socket , with 2 hots a neutral and a ground . That's what it takes to have a neutral and a safety ground. I think the NEC demands those only in hospitals. Everyone else has 2 hots and a not. (safety ground w/ no current) Required for ranges and driers for at least the last 10 years here in Canada - don't know abiout the backwaters of the USA "Whatever for?" he queried, from said backwater. -- If we can ever make red tape nutritional, we can feed the world. --Robert Schaeberle |
#45
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Posted to rec.crafts.metalworking
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On Mon, 28 May 2018 17:19:25 -0700, Larry Jaques
wrote: On Mon, 28 May 2018 11:28:19 -0400, Clare Snyder wrote: On Sun, 27 May 2018 22:24:04 -0700, Larry Jaques wrote: On Sat, 26 May 2018 19:58:13 -0400, Neon John wrote: On Fri, 25 May 2018 11:31:59 -0500, Terry Coombs wrote: * I think you'll find that those 3 pins are neutral and 220 on the other 2 , with either hot to the neutral at 110 . The 3 conductor 240 volt cable is 2 hots and ground. No neutral and thus no 120 volts. Mine has a 4 wire socket , with 2 hots a neutral and a ground . That's what it takes to have a neutral and a safety ground. I think the NEC demands those only in hospitals. Everyone else has 2 hots and a not. (safety ground w/ no current) Required for ranges and driers for at least the last 10 years here in Canada - don't know abiout the backwaters of the USA "Whatever for?" he queried, from said backwater. So you can use 120 volt lightbulbs and timers and primaries on control circuit transformers, and fan motors. and all kinds of other low power devices without (illegally) using the safety ground as a neutral, potentially making the chassis "live" - as has been done, unofficially, for decades - on both dryers and ranges. It's a "safety" thing. They initially allowed the use of the safety ground as a neutral as a matter of expediency due to the high price of copper |
#46
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Posted to rec.crafts.metalworking
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On Mon, 28 May 2018 21:08:33 -0400, Clare Snyder
wrote: On Mon, 28 May 2018 17:19:25 -0700, Larry Jaques wrote: On Mon, 28 May 2018 11:28:19 -0400, Clare Snyder wrote: On Sun, 27 May 2018 22:24:04 -0700, Larry Jaques wrote: On Sat, 26 May 2018 19:58:13 -0400, Neon John wrote: On Fri, 25 May 2018 11:31:59 -0500, Terry Coombs wrote: * I think you'll find that those 3 pins are neutral and 220 on the other 2 , with either hot to the neutral at 110 . The 3 conductor 240 volt cable is 2 hots and ground. No neutral and thus no 120 volts. Mine has a 4 wire socket , with 2 hots a neutral and a ground . That's what it takes to have a neutral and a safety ground. I think the NEC demands those only in hospitals. Everyone else has 2 hots and a not. (safety ground w/ no current) Required for ranges and driers for at least the last 10 years here in Canada - don't know abiout the backwaters of the USA "Whatever for?" he queried, from said backwater. So you can use 120 volt lightbulbs and timers and primaries on control circuit transformers, and fan motors. and all kinds of other low power devices without (illegally) using the safety ground as a neutral, potentially making the chassis "live" - as has been done, unofficially, for decades - on both dryers and ranges. It's a "safety" thing. They initially allowed the use of the safety ground as a neutral as a matter of expediency due to the high price of copper I got used to having the neutral when I was designing lab carts with 240 V DC motors. It was very handy to have 120 V outlets out in the middle of the lab for various tasks. My last set of carts were 440V explosion proof in a classified area, so no outlets on those anyway. I continued the practice when I built my shop, had the electricians pull 4 wire for all my 240 V. circuits. But I haven't had the need since distances are short to plenty of 120 V outlets in the shop. I will probably relocate nearer the coast in the near future. I may end up adding 120 V outlets to the welding cart if needed at the new place. Pete Keillor |
#47
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"Pete Keillor" wrote in message
... On Mon, 28 May 2018 21:08:33 -0400, Clare Snyder wrote: On Mon, 28 May 2018 17:19:25 -0700, Larry Jaques wrote: On Mon, 28 May 2018 11:28:19 -0400, Clare Snyder wrote: On Sun, 27 May 2018 22:24:04 -0700, Larry Jaques wrote: On Sat, 26 May 2018 19:58:13 -0400, Neon John wrote: On Fri, 25 May 2018 11:31:59 -0500, Terry Coombs wrote: I think you'll find that those 3 pins are neutral and 220 on the other 2 , with either hot to the neutral at 110 . The 3 conductor 240 volt cable is 2 hots and ground. No neutral and thus no 120 volts. Mine has a 4 wire socket , with 2 hots a neutral and a ground . That's what it takes to have a neutral and a safety ground. I think the NEC demands those only in hospitals. Everyone else has 2 hots and a not. (safety ground w/ no current) Required for ranges and driers for at least the last 10 years here in Canada - don't know abiout the backwaters of the USA "Whatever for?" he queried, from said backwater. So you can use 120 volt lightbulbs and timers and primaries on control circuit transformers, and fan motors. and all kinds of other low power devices without (illegally) using the safety ground as a neutral, potentially making the chassis "live" - as has been done, unofficially, for decades - on both dryers and ranges. It's a "safety" thing. They initially allowed the use of the safety ground as a neutral as a matter of expediency due to the high price of copper I got used to having the neutral when I was designing lab carts with 240 V DC motors. It was very handy to have 120 V outlets out in the middle of the lab for various tasks. My last set of carts were 440V explosion proof in a classified area, so no outlets on those anyway. I continued the practice when I built my shop, had the electricians pull 4 wire for all my 240 V. circuits. But I haven't had the need since distances are short to plenty of 120 V outlets in the shop. I will probably relocate nearer the coast in the near future. I may end up adding 120 V outlets to the welding cart if needed at the new place. Pete Keillor I was only a few feet away from another tech when he tried to measure an SCR trigger circuit floating on 120V with a grounded scope. When he flipped the power switch the entire probe exploded from the enormous current in the braid, sending him to the hospital. I was facing away and didn't see but I think his body shielded me from the fireball. -jsw |
#48
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On 5/29/2018 8:28 AM, Jim Wilkins wrote:
I was only a few feet away from another tech when he tried to measure an SCR trigger circuit floating on 120V with a grounded scope. When he flipped the power switch the entire probe exploded from the enormous current in the braid, sending him to the hospital. I was facing away and didn't see but I think his body shielded me from the fireball. Defective breaker? |
#49
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Posted to rec.crafts.metalworking
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"Bob Engelhardt" wrote in message
news ![]() On 5/29/2018 8:28 AM, Jim Wilkins wrote: I was only a few feet away from another tech when he tried to measure an SCR trigger circuit floating on 120V with a grounded scope. When he flipped the power switch the entire probe exploded from the enormous current in the braid, sending him to the hospital. I was facing away and didn't see but I think his body shielded me from the fireball. Defective breaker? Parts of the probe remained attached. He had connected the probe ground to the SCR cathode (hot line) so he could observe the optically isolated SCR gate trigger pulse without interference from the 120V sine wave it was riding on. It was a 240V power supply so both sides of the SCRs were Hot. |
#50
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On Mon, 28 May 2018 21:08:33 -0400, Clare Snyder
wrote: On Mon, 28 May 2018 17:19:25 -0700, Larry Jaques wrote: On Mon, 28 May 2018 11:28:19 -0400, Clare Snyder wrote: On Sun, 27 May 2018 22:24:04 -0700, Larry Jaques wrote: On Sat, 26 May 2018 19:58:13 -0400, Neon John wrote: On Fri, 25 May 2018 11:31:59 -0500, Terry Coombs wrote: * I think you'll find that those 3 pins are neutral and 220 on the other 2 , with either hot to the neutral at 110 . The 3 conductor 240 volt cable is 2 hots and ground. No neutral and thus no 120 volts. Mine has a 4 wire socket , with 2 hots a neutral and a ground . That's what it takes to have a neutral and a safety ground. I think the NEC demands those only in hospitals. Everyone else has 2 hots and a not. (safety ground w/ no current) Required for ranges and driers for at least the last 10 years here in Canada - don't know abiout the backwaters of the USA "Whatever for?" he queried, from said backwater. So you can use 120 volt lightbulbs and timers and primaries on control circuit transformers, and fan motors. and all kinds of other low power devices without (illegally) using the safety ground as a neutral, potentially making the chassis "live" - as has been done, unofficially, for decades - on both dryers and ranges. It's a "safety" thing. They initially allowed the use of the safety ground as a neutral as a matter of expediency due to the high price of copper OK, politics, like belt+suspenders. Got it. I'm going to have to ask who plugs those things into dryer outlets, too, I'm afraid. -- If we can ever make red tape nutritional, we can feed the world. --Robert Schaeberle |
#51
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On 5/25/2018 8:40 AM, Dave, I can't do that wrote:
Hi, I have a 1-1/2HP, 220v motor running from the dryer socket, all good. I was thinking of putting in a change over switch to run the motor from the generator when the power goes out as it does regularly out here. https://www.amazon.com/Baomain-Unive.../dp/B01IZ5ZFYC To save me dragging the gen-set out and starting it to find out what is coming out of the 240-socket, thought I'd ask here. The house wiring uses the 3-wire 110-0-110 for the 220/240 but the gen has three pins for the 240-out. I am guessing one is Ground and the others are Neutral and 240v. How do I go about wiring that to run the motor? An ASCII diagram would be good. Thanks Break out your meter and find out. There are 3 pin twist lock 110V plugs. I have a few. |
#52
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On Wed, 30 May 2018 09:58:38 -0700, Bob La Londe
wrote: On 5/25/2018 8:40 AM, Dave, I can't do that wrote: Hi, I have a 1-1/2HP, 220v motor running from the dryer socket, all good. I was thinking of putting in a change over switch to run the motor from the generator when the power goes out as it does regularly out here. https://www.amazon.com/Baomain-Unive.../dp/B01IZ5ZFYC To save me dragging the gen-set out and starting it to find out what is coming out of the 240-socket, thought I'd ask here. The house wiring uses the 3-wire 110-0-110 for the 220/240 but the gen has three pins for the 240-out. I am guessing one is Ground and the others are Neutral and 240v. How do I go about wiring that to run the motor? An ASCII diagram would be good. Thanks Break out your meter and find out. There are 3 pin twist lock 110V plugs. I have a few. Virtually ALL gensets that use a 3 wire twist lock and claim to put out 240 volts...will have 240 across (2) of the connector pins and a ground. The odd shaped pin will be the ground. Least..its supposed to be. Period. Full stop End Program. Measure from 240 pin to ground. You may..may get 120 volts if the genset is worth a ****. I have several gensets..and they include a genset that claims to be 240..but isnt. Gunner --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus |
#53
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"Jim Wilkins" wrote in news
![]() The neutral carries the difference between the hot leg currents. If the load current is 100A on one leg and 0A on the other the neutral will carry 100A. Increasing the load on the other leg decreases the current in the neutral, so with 100A through both hot legs the neutral carries 0A, not 200A, and it can be the same size cable as the two hots. Actually, if the load on the two 120V legs of the 240/120 service is reasonably well balanced, the neutral cable can be substantially *smaller* than the two hots. For example, I just helped my son install a new service panel in his house, upgrading from 100A to 200A service, and he just passed his final electrical inspection last week -- with two 3/0 copper cables for the hots, and 1/0 copper for the neutral. It actually would have passed with the neutral as small as AWG 4, but I happened to have enough 1/0 on hand already, left over from a long-ago project, and neither one of us had any 4. Conceptually you get the right answer if you treat both loops of the circuit as separate and then add the currents, *subtract the currents If the neutral has 100A flowing in from one hot leg and simultaneously 100A out to the other they will sum to 0 Correct. Further example, in case it's unclear to anyone: 75A on one leg and 90A on the other leaves 15A on the neutral. |
#54
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On Tue, 29 May 2018 21:00:02 -0700, Larry Jaques
wrote: On Mon, 28 May 2018 21:08:33 -0400, Clare Snyder wrote: On Mon, 28 May 2018 17:19:25 -0700, Larry Jaques wrote: On Mon, 28 May 2018 11:28:19 -0400, Clare Snyder wrote: On Sun, 27 May 2018 22:24:04 -0700, Larry Jaques wrote: On Sat, 26 May 2018 19:58:13 -0400, Neon John wrote: On Fri, 25 May 2018 11:31:59 -0500, Terry Coombs wrote: * I think you'll find that those 3 pins are neutral and 220 on the other 2 , with either hot to the neutral at 110 . The 3 conductor 240 volt cable is 2 hots and ground. No neutral and thus no 120 volts. Mine has a 4 wire socket , with 2 hots a neutral and a ground . That's what it takes to have a neutral and a safety ground. I think the NEC demands those only in hospitals. Everyone else has 2 hots and a not. (safety ground w/ no current) Required for ranges and driers for at least the last 10 years here in Canada - don't know abiout the backwaters of the USA "Whatever for?" he queried, from said backwater. So you can use 120 volt lightbulbs and timers and primaries on control circuit transformers, and fan motors. and all kinds of other low power devices without (illegally) using the safety ground as a neutral, potentially making the chassis "live" - as has been done, unofficially, for decades - on both dryers and ranges. It's a "safety" thing. They initially allowed the use of the safety ground as a neutral as a matter of expediency due to the high price of copper OK, politics, like belt+suspenders. Got it. I'm going to have to ask who plugs those things into dryer outlets, too, I'm afraid. A welder I had used a 120 volt fan. 240 volt welder. |
#55
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"Doug Miller" wrote in message
. .. "Jim Wilkins" wrote in news ![]() Conceptually you get the right answer if you treat both loops of the circuit as separate and then add the currents, *subtract the currents Adding works if the direction is considered. I would have written 'add algebraically' to an audience of engineers. https://www.conservapedia.com/Algebraic_addition |
#56
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"Jim Wilkins" wrote in news
![]() "Doug Miller" wrote in message . .. "Jim Wilkins" wrote in news ![]() Conceptually you get the right answer if you treat both loops of the circuit as separate and then add the currents, *subtract the currents Adding works if the direction is considered. I would have written 'add algebraically' to an audience of engineers. And I would have understood what you meant. Best to assume, though, IMHO, that most of the people reading this discussion aren't engineers, and would be confused by the terminology. Since one current is arriving, and the other leaving, at the same point, they perforce have opposite signs -- but electricians and laymen don't think that way. They see 70A current on one leg, minus 30A current on the other, equals 40A in the neutral. and don't really care about the fine points of Kirchoff's Current Law. |
#57
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"Doug Miller" wrote in message
. .. "Jim Wilkins" wrote in news ![]() "Doug Miller" wrote in message . .. "Jim Wilkins" wrote in news ![]() Conceptually you get the right answer if you treat both loops of the circuit as separate and then add the currents, *subtract the currents Adding works if the direction is considered. I would have written 'add algebraically' to an audience of engineers. And I would have understood what you meant. Best to assume, though, IMHO, that most of the people reading this discussion aren't engineers, and would be confused by the terminology. Since one current is arriving, and the other leaving, at the same point, they perforce have opposite signs -- but electricians and laymen don't think that way. They see 70A current on one leg, minus 30A current on the other, equals 40A in the neutral. and don't really care about the fine points of Kirchoff's Current Law. Agreed, as long as they stick to single phase. I didn't want to plant an incorrect idea in case they move on to three phase. |
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