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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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ity bity pahse converter
I'm rebuilding a hardinge CHNC...
The machine will be single phase with a VFD for the spindle. I just found out the coolant pump is three phase. It is 1/10 or 1/20 hp. Using a clamp type ampmeter it just tickles the needle on the 6 amp full scale setting. I'll guess .1 to .2 amp per phase. So, would it work to just use a run cap accross L1 L2 L2=wild legto start this thing? How large should I try? If needed, I could use a start delay timer and bring in a cap accross L2 L3. Need this? How large? Karl |
#2
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ity bity pahse converter
Try 3 to 5 MFD and make sure it is not staring under load, once it spins up
to speed close the coolant valve . Be carefull not to allow too much back pressure so that it slows the pump down. You will need to leave the capacitor online. "Karl Townsend" remove .NOT wrote in message k.net... I'm rebuilding a hardinge CHNC... The machine will be single phase with a VFD for the spindle. I just found out the coolant pump is three phase. It is 1/10 or 1/20 hp. Using a clamp type ampmeter it just tickles the needle on the 6 amp full scale setting. I'll guess .1 to .2 amp per phase. So, would it work to just use a run cap accross L1 L2 L2=wild legto start this thing? How large should I try? If needed, I could use a start delay timer and bring in a cap accross L2 L3. Need this? How large? Karl |
#3
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ity bity pahse converter
Item 7568509552 on ebay is a 1/8th hp single phase VFD for $20
Karl Townsend wrote: I'm rebuilding a hardinge CHNC... The machine will be single phase with a VFD for the spindle. I just found out the coolant pump is three phase. It is 1/10 or 1/20 hp. Using a clamp type ampmeter it just tickles the needle on the 6 amp full scale setting. I'll guess .1 to .2 amp per phase. So, would it work to just use a run cap accross L1 L2 L2=wild legto start this thing? How large should I try? If needed, I could use a start delay timer and bring in a cap accross L2 L3. Need this? How large? Karl |
#4
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ity bity pahse converter
"RoyJ" wrote in message .net... Item 7568509552 on ebay is a 1/8th hp single phase VFD for $20 Thanks for the tip. Don't outbid me. Karl |
#5
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ity bity pahse converter
NOT A CHANCE!!
Karl Townsend wrote: "RoyJ" wrote in message .net... Item 7568509552 on ebay is a 1/8th hp single phase VFD for $20 Thanks for the tip. Don't outbid me. Karl |
#6
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ity bity pahse converter
I see you bought it!
RoyJ wrote: NOT A CHANCE!! Karl Townsend wrote: "RoyJ" wrote in message .net... Item 7568509552 on ebay is a 1/8th hp single phase VFD for $20 Thanks for the tip. Don't outbid me. Karl |
#7
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ity bity pahse converter
On Wed, 07 Dec 2005 21:55:22 GMT, "Karl Townsend"
remove .NOT wrote: I'm rebuilding a hardinge CHNC... The machine will be single phase with a VFD for the spindle. I just found out the coolant pump is three phase. It is 1/10 or 1/20 hp. Using a clamp type ampmeter it just tickles the needle on the 6 amp full scale setting. I'll guess .1 to .2 amp per phase. So, would it work to just use a run cap accross L1 L2 L2=wild legto start this thing? How large should I try? If needed, I could use a start delay timer and bring in a cap accross L2 L3. Need this? How large? Karl Don't know if it'similar to your pump but the 1/8 HP centrifugal suds pump on my Schaublin mill needs 16uF start and 4uf run capacitance. Because of their lower efficiency these very small 3 phase motors are more difficult to single phase convert and have dead lousy starting torque. Fortunately this is not much of a problem with a centrifugal pump unless you're you're using a high viscosity neat cutting oil. Because it's a centrifugal pump minimum torque demand is with the delivery turned OFF. In practice it makes precious little difference. Jim |
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