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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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#1
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50 Hz motor on 60 Hz
xray wrote:
I just picked up my first metal lathe. It was originally sold by Warco, a British company, but is a Taiwanese lathe. Made in 1987, it looked pretty dirty, but as I am cleaning and lubing it, it looks pretty good with no major wear. Seems much better than other Chinese lathes I have seen in stores and has nice features -- DTM tool post, Sargon DRO, and built-in coolant pump. So after I cleaned the label on the motor enough to read, I found it is actually a 50 Hz 240 V 1 Hp motor. As far as I know, it has been working fine in California on 60 Hz 220 V power. Should I be concerned about the motor at all? Other than the rated speed being a little off might there be any problems. I haven't even tried to power it up myself yet. Focusing on cleaning years of accumulated dirt and ensuring everything is lubed and free moving. Cleared up a couple of minor issues but it all looks pretty good so far. A 50 Hz motor will run fine on 60Hz power. A 1450 nominal motor will run at 1760 rpm when you go from 50 to 60Hz. A 50Hz motor has more copper than a 60Hz motor. Not all 60Hz motors handle 50Hz well, but the converse is OK. Good luck on that lathe, sounds great with a DRO and all, that's a pretty high-end feature. GWE |
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"xray" wrote in message ... On Tue, 14 Jun 2005 00:25:07 -0700, Grant Erwin wrote: A 50 Hz motor will run fine on 60Hz power. A 1450 nominal motor will run at 1760 rpm when you go from 50 to 60Hz. A 50Hz motor has more copper than a 60Hz motor. Not all 60Hz motors handle 50Hz well, but the converse is OK. Good luck on that lathe, sounds great with a DRO and all, that's a pretty high-end feature. GWE Thanks. Original motor rating was 1720 so I guess it will run at 2064 which seems a little fast for a big motor, but if it has lasted this long, I guess it will likely continue. SNIP There is no such animal as a 50hz 1720 rpm induction motor. I suspect the rating plate has either been mis-stamped or misread. For a four pole motor, the 50hz synchronous speed is 1500 rpm. At 60hz, this becomes 1800 rpm. A two pole motor at 50hz is 3000 rpm, at 60hz this becomes 3600. Non synchronous motors run at a speed approx 5% slower due to magnetic slippage. -- Regards, Chas. To Email, replace 'xxx' with tango papa golf. |
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Chas sez:
Chas sez: " There is no such animal as a 50hz 1720 rpm induction motor. I suspect the rating plate has either been mis-stamped or misread. For a four pole motor, the 50hz synchronous speed is 1500 rpm. At 60hz, this becomes 1800 rpm. A two pole motor at 50hz is 3000 rpm, at 60hz this becomes 3600. Non synchronous motors run at a speed approx 5% slower due to magnetic slippage." I suspect you misread Grant's reply. He said a 1450 rpm, 50 hz motor running on 60 hz would run at nominal 1760 rpm. That may be a little high, but you get the idea. Bob Swinney "Chas" wrote in message ... "xray" wrote in message ... On Tue, 14 Jun 2005 00:25:07 -0700, Grant Erwin wrote: A 50 Hz motor will run fine on 60Hz power. A 1450 nominal motor will run at 1760 rpm when you go from 50 to 60Hz. A 50Hz motor has more copper than a 60Hz motor. Not all 60Hz motors handle 50Hz well, but the converse is OK. Good luck on that lathe, sounds great with a DRO and all, that's a pretty high-end feature. GWE Thanks. Original motor rating was 1720 so I guess it will run at 2064 which seems a little fast for a big motor, but if it has lasted this long, I guess it will likely continue. SNIP -- Regards, Chas. To Email, replace 'xxx' with tango papa golf. |
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xray wrote:
On Tue, 14 Jun 2005 00:25:07 -0700, Grant Erwin wrote: A 50 Hz motor will run fine on 60Hz power. A 1450 nominal motor will run at 1760 rpm when you go from 50 to 60Hz. A 50Hz motor has more copper than a 60Hz motor. Not all 60Hz motors handle 50Hz well, but the converse is OK. Good luck on that lathe, sounds great with a DRO and all, that's a pretty high-end feature. GWE Thanks. Original motor rating was 1720 so I guess it will run at 2064 which seems a little fast for a big motor, but if it has lasted this long, I guess it will likely continue. Get out your reading glasses and a good light and clean off that motor nameplate and have another look. It's entirely possible it may have nameplate specs for both frequency (50/60Hz) and rpm, and that you've picked up 50Hz from one and 1720 rpm from the other. 1720 is what it will run on 60Hz power, not 50. - GWE |
#5
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If the original motor RPM was 1720, I suggest you clean the data plate
on the motor off a little better and look at it with a magnifying glass. I suspect the 1720 is the RPM for 60 hertz. Dan |
#6
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Sooo...
Power it up.. take a tach read and tell us what it really turned out to be :-) Dave "xray" wrote in message ... On 14 Jun 2005 08:14:40 -0700, " wrote: If the original motor RPM was 1720, I suggest you clean the data plate on the motor off a little better and look at it with a magnifying glass. I suspect the 1720 is the RPM for 60 hertz. Dan After reading everyone's replies, I went and looked again. It's more ambiguous now. The power, voltage and Hz are stamped on the label but the rpm is printed. So it's probably a screw up in their labeling and the printed rpm value is for 60 Hz. To complicate things more, the 5 in 50 could be interpreted as a 6. The bottom half isn't obviously open (as in 5) but the top half is square (as in 5). The voltage rating being at 240 seems to make it not a normal 60 Hz motor so I assume it is 50 Hz. Anyway, from what has been said, seems that it should work ok even if it is a 50 Hz motor. As far as I know it has been used in this area for quite a while, so I'll assume it will be ok. |
#7
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On Thu, 16 Jun 2005 03:38:16 GMT, "Dave August"
wrote: Sooo... Power it up.. take a tach read and tell us what it really turned out to be :-) Dave "xray" wrote in message .. . On 14 Jun 2005 08:14:40 -0700, " wrote: If the original motor RPM was 1720, I suggest you clean the data plate on the motor off a little better and look at it with a magnifying glass. I suspect the 1720 is the RPM for 60 hertz. Dan After reading everyone's replies, I went and looked again. It's more ambiguous now. The power, voltage and Hz are stamped on the label but the rpm is printed. So it's probably a screw up in their labeling and the printed rpm value is for 60 Hz. To complicate things more, the 5 in 50 could be interpreted as a 6. The bottom half isn't obviously open (as in 5) but the top half is square (as in 5). The voltage rating being at 240 seems to make it not a normal 60 Hz motor so I assume it is 50 Hz. Anyway, from what has been said, seems that it should work ok even if it is a 50 Hz motor. As far as I know it has been used in this area for quite a while, so I'll assume it will be ok. A 50hz motor on 60 will just run fast, while a 60hz on 50 may overheat, as a 50hz device needs more iron. |
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