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09-04-2019, 01:11 AM
(This post was last modified: 09-04-2019, 01:17 AM by awemawson.)
There is little dispute that a three phase motor runs more smoothly than a single phase one, for exactly the same reason that an internal combustion engine runs more smoothly the more cylinders it has.
The Jones and Shipman 540 surface grinder has a specially balanced three phase motor, and it is apparent in the finish if it has been replaced, as some do if they don’t have three phase, with an off the shelf single phase one. Now some of this effect is due to the precision balanced armature, but some definitely is due to the single phase nature of the replacement.
Andrew Mawson, proud to be a member of MetalworkingFun Forum since Oct 2013.
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Converting my lowly import lathe to three phase made a big difference in how smoothly it runs now, and the quality of the finishes I get. I imagine the impact on a surface grinder has to be ten fold by comparison.
Willie
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With the grinding wheel acting as a flywheel I can't see 3 phase making much difference. Can you tell if a car has a 4 or 8 cylinder engine when driving down the road.
Free advice is worth exactly what you payed for it.
Greg
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09-04-2019, 02:28 PM
(This post was last modified: 09-04-2019, 02:32 PM by awemawson.)
Yes unless you always drive with the radio turned on full wack 
(Chasing away odd herring bone and other repeating patterns on surface ground work has left me with a healthy respect for how little unbalance can cause problems with working to fine tolerances)
Andrew Mawson, proud to be a member of MetalworkingFun Forum since Oct 2013.
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(09-04-2019, 12:18 PM)f350ca Wrote: Can you tell if a car has a 4 or 8 cylinder engine when driving down the road.
Not so much DOWN the road no, but going UP the road under load - yes, most definitely. 
Back in my days on 2 wheels, I had a Honda inline-4 that I could stand a nickle on edge sitting on the fuel tank - and rev the engine full throttle, and the nickle would not move. If I tried that with my later model Harley-Davidson V-twin, I would have to super glue the nickle flat to the tank - and the nickle would still fall off at IDLE!
Truth be told, the shift lever fell off on the highway two weeks after I bought it brand new! THAT is how badly the thing vibrated. 
Even with a 3-phase motor some grinders have to resort to using air bearings to keep down the level of vibrations do they not? 
Yeah, I'm blathering...
Willie
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The bearings showed up today - YAY!!! Got the ones for the idler pressed in and put back together. It's a whole bunch quieter now!
The VFD showed up too, it's good to 3HP so I think I'm going to use that for a larger/better motor for the spindle. Now to find a smaller one (or two) for the table feed and maybe for the surface grinder.
Looks like I got some more electrical to do!
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(09-09-2019, 10:10 PM)Vinny Wrote: The bearings showed up today - YAY!!! Got the ones for the idler pressed in and put back together. It's a whole bunch quieter now!
The VFD showed up too, it's good to 3HP so I think I'm going to use that for a larger/better motor for the spindle. Now to find a smaller one (or two) for the table feed and maybe for the surface grinder.
Looks like I got some more electrical to do!
Whats the matter? You BORED or something?
Willie
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(09-09-2019, 10:10 PM)Vinny Wrote: The bearings showed up today - YAY!!! Got the ones for the idler pressed in and put back together. It's a whole bunch quieter now!
The VFD showed up too, it's good to 3HP so I think I'm going to use that for a larger/better motor for the spindle. Now to find a smaller one (or two) for the table feed and maybe for the surface grinder.
Looks like I got some more electrical to do!
I recommend taking a look at the offerings at the Surplus Center. I've purchased a number of motors and other supplies from them at reasonable prices. The main issue I have with them is their shipping tends to be on the high side.
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Just got off the fone with a local guy who has a 1HP 3P motor - NEW - for $50. They ordered 4 machines, all 4 had the 1HP motors and should've had 2HP. They replaced all of them with 2HP and my name is now on one of the pulled motors. I'll pick it up this weekend when he gets back into town.
Also got some Huok cabinets for endmills, drills, reamers, ... at an auction. That will free up some drawers to put better stuff in. Got some other stuff that I'll post when I pick it up.
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09-10-2019, 06:07 PM
(This post was last modified: 09-10-2019, 06:09 PM by Dr Stan.)
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