Electric motor lubrication
I have an old (1947±) LeBlonde Regal lathe. The huge motor (G.E. probably
only 2 hp) has grease fittings on each end (motor housing). Do I really use grease? Do I replace the zerks with cups and add oil? Or do I modify my grease gun to use oil? All advise appreciated. Ivan Vegvary |
Electric motor lubrication
"Ivan Vegvary" wrote in message ... I have an old (1947±) LeBlonde Regal lathe. The huge motor (G.E. probably only 2 hp) has grease fittings on each end (motor housing). Do I really use grease? Do I replace the zerks with cups and add oil? Or do I modify my grease gun to use oil? All advise appreciated. Ivan Vegvary Hi Ivan, I used to run an early '60s Devlieg jig mill at work with a huge motor that also had grease fittings at each end. We did (and still do) use grease in it. Ours has plugs on the opposite side of the housing from the zerks that need to be removed before new grease is added or you'll blow out the seals and pump the motor full of grease. We just pull out the plugs and pump in new grease thru the zerk till the new grease starts coming out of the plug hole and replace the plugs. Paul |
Electric motor lubrication
I have an even older Wagner 7.5 HP motor with grease fittings on each end. Grease is a way to keep
something oiled without having to tend to it very often. Think of grease as it was originally . . . oil absorbed into soap flakes. Bob Swinney "Paul" wrote in message ... "Ivan Vegvary" wrote in message ... I have an old (1947±) LeBlonde Regal lathe. The huge motor (G.E. probably only 2 hp) has grease fittings on each end (motor housing). Do I really use grease? Do I replace the zerks with cups and add oil? Or do I modify my grease gun to use oil? All advise appreciated. Ivan Vegvary Hi Ivan, I used to run an early '60s Devlieg jig mill at work with a huge motor that also had grease fittings at each end. We did (and still do) use grease in it. Ours has plugs on the opposite side of the housing from the zerks that need to be removed before new grease is added or you'll blow out the seals and pump the motor full of grease. We just pull out the plugs and pump in new grease thru the zerk till the new grease starts coming out of the plug hole and replace the plugs. Paul |
Electric motor lubrication
On Tue, 30 Sep 2008 20:01:08 -0500, "Robert Swinney"
wrote: I have an even older Wagner 7.5 HP motor with grease fittings on each end. Grease is a way to keep something oiled without having to tend to it very often. Think of grease as it was originally . . . oil absorbed into soap flakes. Bob Swinney "Paul" wrote in message ... "Ivan Vegvary" wrote in message ... I have an old (1947±) LeBlonde Regal lathe. The huge motor (G.E. probably only 2 hp) has grease fittings on each end (motor housing). Do I really use grease? Do I replace the zerks with cups and add oil? Or do I modify my grease gun to use oil? All advise appreciated. Ivan Vegvary Hi Ivan, I used to run an early '60s Devlieg jig mill at work with a huge motor that also had grease fittings at each end. We did (and still do) use grease in it. Ours has plugs on the opposite side of the housing from the zerks that need to be removed before new grease is added or you'll blow out the seals and pump the motor full of grease. We just pull out the plugs and pump in new grease thru the zerk till the new grease starts coming out of the plug hole and replace the plugs. Paul Over lubrication is the primary cause of premature bearing failure. Check out lube recommendations on the bearing or grease manufacturers web site. Depending on the capacity of your grease gun usually a couple of shots periodically will suffice. |
Electric motor lubrication
Christopher Tidy wrote:
Robert Swinney wrote: I have an even older Wagner 7.5 HP motor with grease fittings on each end. Grease is a way to keep something oiled without having to tend to it very often. Think of grease as it was originally . . . oil absorbed into soap flakes. Interesting. I never heard that before. I had always assumed that the first grease was derived from animal fat. ... soap being of course animal fat boiled up with lye Grant ** Posted from http://www.teranews.com ** |
Electric motor lubrication
Robert Swinney wrote:
I have an even older Wagner 7.5 HP motor with grease fittings on each end. Grease is a way to keep something oiled without having to tend to it very often. Think of grease as it was originally . . . oil absorbed into soap flakes. Interesting. I never heard that before. I had always assumed that the first grease was derived from animal fat. Best wishes, Chris |
Electric motor lubrication
REMOVE Tom wrote:
Over lubrication is the primary cause of premature bearing failure. Check out lube recommendations on the bearing or grease manufacturers web site. Depending on the capacity of your grease gun usually a couple of shots periodically will suffice. Is that true? What damage does it do to the bearings? The worst I've seen is for the excess grease to squirt out and make a mess. Best wishes, Chris |
Electric motor lubrication
On Oct 9, 9:55*pm, Christopher Tidy
wrote: REMOVE Tom wrote: Over lubrication is the primary cause of premature bearing failure. Check out lube recommendations on the bearing or grease manufacturers web site. Depending on the capacity of your grease gun usually a couple of shots periodically will suffice. Is that true? What damage does it do to the bearings? The worst I've seen is for the excess grease to squirt out and make a mess. Too much greease in a high speed bearing can very easily cause it to overheat. Small 1800 rpm motors will have no problems with overgreasing other than the mess. Best wishes, Chris |
Electric motor lubrication
On Fri, 10 Oct 2008 01:55:12 +0000, Christopher Tidy
wrote: REMOVE Tom wrote: Over lubrication is the primary cause of premature bearing failure. Check out lube recommendations on the bearing or grease manufacturers web site. Depending on the capacity of your grease gun usually a couple of shots periodically will suffice. Is that true? What damage does it do to the bearings? The worst I've seen is for the excess grease to squirt out and make a mess. Best wishes, Chris Grease is a great insulator - the rollers will push it out of their path forming a wall which prevents it from dissipating the heat. |
Electric motor lubrication
On Oct 10, 7:54*pm, Christopher Tidy
wrote: Grant Erwin wrote: Christopher Tidy wrote: Robert Swinney wrote: I have an even older Wagner 7.5 HP motor with grease fittings on each end. *Grease is a way to keep something oiled without having to tend to it very often. *Think of grease as it was originally . . . oil absorbed into soap flakes. Interesting. I never heard that before. I had always assumed that the first grease was derived from animal fat. .. soap being of course animal fat boiled up with lye Good point, Grant. I'd overlooked that. Does anyone know of a book which describes the process of making grease from oil and soap flakes? I'd be interested to read about it. Best wishes, Chris Mix and stir. http://en.wikipedia.org/wiki/Grease_(lubricant) |
Electric motor lubrication
REMOVE Tom wrote:
On Fri, 10 Oct 2008 01:55:12 +0000, Christopher Tidy wrote: REMOVE Tom wrote: Over lubrication is the primary cause of premature bearing failure. Check out lube recommendations on the bearing or grease manufacturers web site. Depending on the capacity of your grease gun usually a couple of shots periodically will suffice. Is that true? What damage does it do to the bearings? The worst I've seen is for the excess grease to squirt out and make a mess. Best wishes, Chris Grease is a great insulator - the rollers will push it out of their path forming a wall which prevents it from dissipating the heat. Surely this is only going to be a problem in bearings which run at tens of thousands of rpm? Best wishes, Chris |
Electric motor lubrication
Grant Erwin wrote:
Christopher Tidy wrote: Robert Swinney wrote: I have an even older Wagner 7.5 HP motor with grease fittings on each end. Grease is a way to keep something oiled without having to tend to it very often. Think of grease as it was originally . . . oil absorbed into soap flakes. Interesting. I never heard that before. I had always assumed that the first grease was derived from animal fat. .. soap being of course animal fat boiled up with lye Good point, Grant. I'd overlooked that. Does anyone know of a book which describes the process of making grease from oil and soap flakes? I'd be interested to read about it. Best wishes, Chris |
Electric motor lubrication
On Fri, 10 Oct 2008 23:54:32 +0000, Christopher Tidy
wrote: Grant Erwin wrote: Christopher Tidy wrote: Robert Swinney wrote: I have an even older Wagner 7.5 HP motor with grease fittings on each end. Grease is a way to keep something oiled without having to tend to it very often. Think of grease as it was originally . . . oil absorbed into soap flakes. Interesting. I never heard that before. I had always assumed that the first grease was derived from animal fat. .. soap being of course animal fat boiled up with lye Good point, Grant. I'd overlooked that. Does anyone know of a book which describes the process of making grease from oil and soap flakes? I'd be interested to read about it. Best wishes, Chris The "soap" isn't necessarily something you would wash with. Lithium is one "soap" used. So is Sodium, and Barium, as well as Calcium and aluminum. All the above are considered "soap" type greases. I don't know of any grease in common use made from Lye soap (or Ivory Snow) ** Posted from http://www.teranews.com ** |
Electric motor lubrication
On 2008-10-10, Christopher Tidy wrote:
REMOVE Tom wrote: [ ... ] Grease is a great insulator - the rollers will push it out of their path forming a wall which prevents it from dissipating the heat. Surely this is only going to be a problem in bearings which run at tens of thousands of rpm? That depends on the size of the bearing. let's say for a 1/4" ID bearing, the balls run at approximately a 1/2" diameter, and get the SFM for that at 10,000 RPM as a starting point: 1309 SFM Now -- let's take the shaft diameter up to say 2", and say perhaps 2-1/2" for the diameter of the bearing ball's path: 5208 SFM And a really serious electric motor with a 6" shaft (you can guess the horsepower rating if you wish), and probably 8" diameter bearing ball path: 20,943 SFM So -- at what speed does the grease migration start to become a problem? Assuming the 1039 SFM as the top acceptable one with the 1/4" shaft, we get 625 RPM for the maximum speed for the 6" shaft. And how big *do* electric motor shafts get? (Of course, the larger ones do run slower to keep from self-disassembly. :-) Enjoy, DoN. -- Email: | Voice (all times): (703) 938-4564 (too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html --- Black Holes are where God is dividing by zero --- |
Electric motor lubrication
"Christopher Tidy" wrote in message ... Gunner wrote: On Fri, 10 Oct 2008 23:52:01 +0000, Christopher Tidy wrote: REMOVE Tom wrote: On Fri, 10 Oct 2008 01:55:12 +0000, Christopher Tidy wrote: REMOVE Tom wrote: Over lubrication is the primary cause of premature bearing failure. Check out lube recommendations on the bearing or grease manufacturers web site. Depending on the capacity of your grease gun usually a couple of shots periodically will suffice. Is that true? What damage does it do to the bearings? The worst I've seen is for the excess grease to squirt out and make a mess. Best wishes, Chris Grease is a great insulator - the rollers will push it out of their path forming a wall which prevents it from dissipating the heat. Surely this is only going to be a problem in bearings which run at tens of thousands of rpm? Best wishes, Chris Over greased bearings start heating up at 1500 rpm I've sometimes seen two maximum speeds quoted on bearing data sheets: a lower speed for grease lubrication and a higher speed for oil lubrication. I guess the advantage of oil is that it can circulate and carry the heat away, so it doesn't have to rely heavily on thermal conduction. Best wishes, Chris I don't think thermal conduction is the culprit. I am pretty sure that the friction from churning the higher viscosity lubricant raises the temperature. It is an effect not commonly thought of but you can get an idea by running a power paint stirrer in thick paint. Essentially all of the power it takes to spin the stirrer is converted to heat. I had a "bush-hog" gearbox overheat and ruin the seals because I had put in oil which was too thick. Don Young |
Electric motor lubrication
On Fri, 10 Oct 2008 23:52:01 +0000, Christopher Tidy
wrote: REMOVE Tom wrote: On Fri, 10 Oct 2008 01:55:12 +0000, Christopher Tidy wrote: REMOVE Tom wrote: Over lubrication is the primary cause of premature bearing failure. Check out lube recommendations on the bearing or grease manufacturers web site. Depending on the capacity of your grease gun usually a couple of shots periodically will suffice. Is that true? What damage does it do to the bearings? The worst I've seen is for the excess grease to squirt out and make a mess. Best wishes, Chris Grease is a great insulator - the rollers will push it out of their path forming a wall which prevents it from dissipating the heat. Surely this is only going to be a problem in bearings which run at tens of thousands of rpm? Best wishes, Chris Over greased bearings start heating up at 1500 rpm |
Electric motor lubrication
Jim Wilkins wrote:
On Oct 10, 7:54 pm, Christopher Tidy wrote: Grant Erwin wrote: Christopher Tidy wrote: Robert Swinney wrote: I have an even older Wagner 7.5 HP motor with grease fittings on each end. Grease is a way to keep something oiled without having to tend to it very often. Think of grease as it was originally . . . oil absorbed into soap flakes. Interesting. I never heard that before. I had always assumed that the first grease was derived from animal fat. .. soap being of course animal fat boiled up with lye Good point, Grant. I'd overlooked that. Does anyone know of a book which describes the process of making grease from oil and soap flakes? I'd be interested to read about it. Best wishes, Chris Mix and stir. http://en.wikipedia.org/wiki/Grease_(lubricant) Thanks, Jim. Is it not possible to end up with a solid by distilling off all the light fractions from crude oil? Or is that solid just tar, as opposed to a useful lubricant? I learnt something interesting. Best wishes, Chris |
Electric motor lubrication
DoN. Nichols wrote:
On 2008-10-10, Christopher Tidy wrote: REMOVE Tom wrote: [ ... ] Grease is a great insulator - the rollers will push it out of their path forming a wall which prevents it from dissipating the heat. Surely this is only going to be a problem in bearings which run at tens of thousands of rpm? That depends on the size of the bearing. let's say for a 1/4" ID bearing, the balls run at approximately a 1/2" diameter, and get the SFM for that at 10,000 RPM as a starting point: 1309 SFM Now -- let's take the shaft diameter up to say 2", and say perhaps 2-1/2" for the diameter of the bearing ball's path: 5208 SFM And a really serious electric motor with a 6" shaft (you can guess the horsepower rating if you wish), and probably 8" diameter bearing ball path: 20,943 SFM I'm thinking a few thousand horsepower for a 6" diameter shaft at 625 rpm, but that's just a guess. So -- at what speed does the grease migration start to become a problem? I thought the issue Tom was talking about was the thermal insulating effect of a thick grease barrier? Assuming the 1039 SFM as the top acceptable one with the 1/4" shaft, we get 625 RPM for the maximum speed for the 6" shaft. And how big *do* electric motor shafts get? (Of course, the larger ones do run slower to keep from self-disassembly. :-) Well, I've seen alternators with 12" diameter shafts at a place where I had a summer job once. But they had plain bearings. Hydrostatic when starting, hydrodynamic when up to speed. Rumour has it than when the oil pump is switched on, you can rotate a 90-ton rotor in those bearings by hand. That's what I was told anyway. Perhaps your reasoning explains why they don't use roller bearings in those huge alternators, as they do 3,000 rpm. I just remember being told that rolling element bearings didn't survive under those conditions. I've also seen a ship with a half metre diameter propellor shaft (apparently solid too). Best wishes, Chris |
Electric motor lubrication
Gunner wrote:
On Fri, 10 Oct 2008 23:52:01 +0000, Christopher Tidy wrote: REMOVE Tom wrote: On Fri, 10 Oct 2008 01:55:12 +0000, Christopher Tidy wrote: REMOVE Tom wrote: Over lubrication is the primary cause of premature bearing failure. Check out lube recommendations on the bearing or grease manufacturers web site. Depending on the capacity of your grease gun usually a couple of shots periodically will suffice. Is that true? What damage does it do to the bearings? The worst I've seen is for the excess grease to squirt out and make a mess. Best wishes, Chris Grease is a great insulator - the rollers will push it out of their path forming a wall which prevents it from dissipating the heat. Surely this is only going to be a problem in bearings which run at tens of thousands of rpm? Best wishes, Chris Over greased bearings start heating up at 1500 rpm I've sometimes seen two maximum speeds quoted on bearing data sheets: a lower speed for grease lubrication and a higher speed for oil lubrication. I guess the advantage of oil is that it can circulate and carry the heat away, so it doesn't have to rely heavily on thermal conduction. Best wishes, Chris |
Electric motor lubrication
clare wrote:
On Fri, 10 Oct 2008 23:54:32 +0000, Christopher Tidy wrote: Grant Erwin wrote: Christopher Tidy wrote: Robert Swinney wrote: I have an even older Wagner 7.5 HP motor with grease fittings on each end. Grease is a way to keep something oiled without having to tend to it very often. Think of grease as it was originally . . . oil absorbed into soap flakes. Interesting. I never heard that before. I had always assumed that the first grease was derived from animal fat. .. soap being of course animal fat boiled up with lye Good point, Grant. I'd overlooked that. Does anyone know of a book which describes the process of making grease from oil and soap flakes? I'd be interested to read about it. Best wishes, Chris The "soap" isn't necessarily something you would wash with. Lithium is one "soap" used. So is Sodium, and Barium, as well as Calcium and aluminum. All the above are considered "soap" type greases. I don't know of any grease in common use made from Lye soap (or Ivory Snow) Thanks for making that distinction. Best wishes, Chris |
Electric motor lubrication
In article ,
Christopher Tidy wrote: Surely this is only going to be a problem in bearings which run at tens of thousands of rpm? http://freefall.purrsia.com/ff600/fv00563.htm -- -Ed Falk, http://thespamdiaries.blogspot.com/ |
Electric motor lubrication
You're correct. The bearing has to "work harder" and the heat has
nowhere to go. Speeds son't have to be all that great. On Sat, 11 Oct 2008 20:35:10 -0500, "Don Young" wrote: "Christopher Tidy" wrote in message ... Gunner wrote: On Fri, 10 Oct 2008 23:52:01 +0000, Christopher Tidy wrote: REMOVE Tom wrote: On Fri, 10 Oct 2008 01:55:12 +0000, Christopher Tidy wrote: REMOVE Tom wrote: Over lubrication is the primary cause of premature bearing failure. Check out lube recommendations on the bearing or grease manufacturers web site. Depending on the capacity of your grease gun usually a couple of shots periodically will suffice. Is that true? What damage does it do to the bearings? The worst I've seen is for the excess grease to squirt out and make a mess. Best wishes, Chris Grease is a great insulator - the rollers will push it out of their path forming a wall which prevents it from dissipating the heat. Surely this is only going to be a problem in bearings which run at tens of thousands of rpm? Best wishes, Chris Over greased bearings start heating up at 1500 rpm I've sometimes seen two maximum speeds quoted on bearing data sheets: a lower speed for grease lubrication and a higher speed for oil lubrication. I guess the advantage of oil is that it can circulate and carry the heat away, so it doesn't have to rely heavily on thermal conduction. Best wishes, Chris I don't think thermal conduction is the culprit. I am pretty sure that the friction from churning the higher viscosity lubricant raises the temperature. It is an effect not commonly thought of but you can get an idea by running a power paint stirrer in thick paint. Essentially all of the power it takes to spin the stirrer is converted to heat. I had a "bush-hog" gearbox overheat and ruin the seals because I had put in oil which was too thick. Don Young |
Electric motor lubrication
Don Young wrote:
"Christopher Tidy" wrote in message ... Gunner wrote: On Fri, 10 Oct 2008 23:52:01 +0000, Christopher Tidy wrote: REMOVE Tom wrote: On Fri, 10 Oct 2008 01:55:12 +0000, Christopher Tidy wrote: REMOVE Tom wrote: Over lubrication is the primary cause of premature bearing failure. Check out lube recommendations on the bearing or grease manufacturers web site. Depending on the capacity of your grease gun usually a couple of shots periodically will suffice. Is that true? What damage does it do to the bearings? The worst I've seen is for the excess grease to squirt out and make a mess. Best wishes, Chris Grease is a great insulator - the rollers will push it out of their path forming a wall which prevents it from dissipating the heat. Surely this is only going to be a problem in bearings which run at tens of thousands of rpm? Best wishes, Chris Over greased bearings start heating up at 1500 rpm I've sometimes seen two maximum speeds quoted on bearing data sheets: a lower speed for grease lubrication and a higher speed for oil lubrication. I guess the advantage of oil is that it can circulate and carry the heat away, so it doesn't have to rely heavily on thermal conduction. Best wishes, Chris I don't think thermal conduction is the culprit. I am pretty sure that the friction from churning the higher viscosity lubricant raises the temperature. It is an effect not commonly thought of but you can get an idea by running a power paint stirrer in thick paint. Essentially all of the power it takes to spin the stirrer is converted to heat. I had a "bush-hog" gearbox overheat and ruin the seals because I had put in oil which was too thick. Right, Don. Thanks. Got it now! Best wishes, Chris |
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