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After researching of motors are 221°F [105°C] after that the life is shortened.? The outside temperature is about? 60°F to 70°F? [15 to 20°C ] less the coil temperature.? So if outside is could be wend the coil is? 221°F [105°C] the outside is between? 151°F and 161°F [85 an 90°C]. On my gauge I set the red mark at 80°C and 105°C.? If I see gets never red it time to let motor cool down and gives little to finish the cut.? The Capillary is attached by HVAC Aluminum tape , max temperature is 145 °C at this point the motor is toast? Dave?   
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FYI?
If motor is over 145°F [63°C] do not touch it will burn.
So can be burn at a lower temperature and some can go above.
Dave?
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Thermal images of the LMS motor? -
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On 4/30/2024 4:36 PM, davesmith1800 via groups.io wrote: After researching of motors are 221°F [105°C] after that the life is shortened.
The outside temperature is about? 60°F to 70°F? [15 to 20°C ] less the coil temperature.? So if outside is could be wend the coil is? 221°F [105°C] the outside is between? 151°F and 161°F [85 an 90°C].
On my gauge I set the red mark at 80°C and 105°C.
If I see gets never red it time to let motor cool down and gives little to finish the cut.
The Capillary is attached by HVAC Aluminum tape , max temperature is 145 °C at this point the motor is toast
Dave
Attachments:
20240429_111501.jpg: /g/7x12MiniLathe/attachment/119482/
20240430_111809.jpg: /g/7x12MiniLathe/attachment/119482/1
20240430_122140.jpg: /g/7x12MiniLathe/attachment/119482/2
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50% of motors running full speed the bearings will only last 20,000 hour but the coil last a lot longer dust is next problem.??
But biggest reason failed of a motor running lower speed is over heating. The fan is not running fast enough to cool the motor.? This because cutting low speed under heavy load.? This is our problem on mini lathes.
The speed is 100 rpm and the fan turns slowly.?
If turning at 2,000 rpm the fan is doing? a great job of cooling.??
I have seen 30 hp DC motors on machine tools. They add a very large fan for cooling.?
It hard to put a good cooling fan in a tight spot.?
Dave?
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On Tue, Apr 30, 2024 at 02:28 PM, WAM wrote:
Thermal images of the LMS motor? -
On 4/30/2024 4:36 PM, davesmith1800 via groups.io wrote:
After researching of motors are 221°F [105°C] after that the life is shortened.
The outside temperature is about? 60°F to 70°F? [15 to 20°C ] less the coil temperature.? So if outside is could be wend the coil is? 221°F [105°C] the outside is between? 151°F and 161°F [85 an 90°C].
On my gauge I set the red mark at 80°C and 105°C.
If I see gets never red it time to let motor cool down and gives little to finish the cut.
The Capillary is attached by HVAC Aluminum tape , max temperature is 145 °C at this point the motor is toast
Dave
Attachments:
20240429_111501.jpg: /g/7x12MiniLathe/attachment/119482/
20240430_111809.jpg: /g/7x12MiniLathe/attachment/119482/1
20240430_122140.jpg: /g/7x12MiniLathe/attachment/119482/2
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It's a good example of why ya should have a few old computer fans
in yer inventory .
animal
On 4/30/24 3:56 PM, davesmith1800
wrote:
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Show quoted text
50% of motors running full speed the bearings will only last
20,000 hour but the coil last a lot longer dust is next problem.??
But biggest reason failed of a motor running lower speed is over
heating. The fan is not running fast enough to cool the motor.?
This because cutting low speed under heavy load.? This is our
problem on mini lathes.
The speed is 100 rpm and the fan turns slowly.?
If turning at 2,000 rpm the fan is doing? a great job of
cooling.??
I have seen 30 hp DC motors on machine tools. They add a very
large fan for cooling.?
It hard to put a good cooling fan in a tight spot.?
Dave?
On Tue, Apr 30, 2024 at 02:28 PM, WAM wrote:
Thermal images of the LMS motor? -
On 4/30/2024 4:36 PM, davesmith1800 via groups.io wrote:
After researching of motors are 221°F [105°C] after
that the life is shortened.
The outside temperature is about? 60°F to 70°F? [15 to 20°C ]
less the coil temperature.? So if outside is could be wend the
coil is? 221°F [105°C] the outside is between? 151°F and 161°F
[85 an 90°C].
On my gauge I set the red mark at 80°C and 105°C.
If I see gets never red it time to let motor cool down and
gives little to finish the cut.
The Capillary is attached by HVAC Aluminum tape , max
temperature is 145 °C at this point the motor is toast
Dave
Attachments:
20240429_111501.jpg: /g/7x12MiniLathe/attachment/119482/
20240430_111809.jpg: /g/7x12MiniLathe/attachment/119482/1
20240430_122140.jpg: /g/7x12MiniLathe/attachment/119482/2
|
I have fans.
I was more interested in know what real temperature is before something happens.??
If ot is big problem I will add a fan. But still keep the temperature gauge just case the fan fails?
It like car water temperature you know what temperature before you see smoke coming out of the hood.??
Dave?
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On Tue, Apr 30, 2024 at 04:34 PM, mike allen wrote:
It's a good example of why ya should have a few old computer fans in yer inventory .
animal
On 4/30/24 3:56 PM, davesmith1800 wrote:
50% of motors running full speed the bearings will only last 20,000 hour but the coil last a lot longer dust is next problem.??
But biggest reason failed of a motor running lower speed is over heating. The fan is not running fast enough to cool the motor.? This because cutting low speed under heavy load.? This is our problem on mini lathes.
The speed is 100 rpm and the fan turns slowly.?
If turning at 2,000 rpm the fan is doing? a great job of cooling.??
I have seen 30 hp DC motors on machine tools. They add a very large fan for cooling.?
It hard to put a good cooling fan in a tight spot.?
Dave?
On Tue, Apr 30, 2024 at 02:28 PM, WAM wrote:
Thermal images of the LMS motor? -
On 4/30/2024 4:36 PM, davesmith1800 via groups.io wrote:
After researching of motors are 221°F [105°C] after that the life is shortened.
The outside temperature is about? 60°F to 70°F? [15 to 20°C ] less the coil temperature.? So if outside is could be wend the coil is? 221°F [105°C] the outside is between? 151°F and 161°F [85 an 90°C].
On my gauge I set the red mark at 80°C and 105°C.
If I see gets never red it time to let motor cool down and gives little to finish the cut.
The Capillary is attached by HVAC Aluminum tape , max temperature is 145 °C at this point the motor is toast
Dave
Attachments:
20240429_111501.jpg: /g/7x12MiniLathe/attachment/119482/
20240430_111809.jpg: /g/7x12MiniLathe/attachment/119482/1
20240430_122140.jpg: /g/7x12MiniLathe/attachment/119482/2
|
Here the finished install.? 1) The first shows the the blue is heat shink tube with a sealer to protect the tubing left a little coil on the outside if gauge needs to be removed.? 2) The second? Shows the Capillary blub on the motor using HVAC Aluminum tape. Tape goes over 284°F [140°C] 3) The last photo photo shows read to go. It tilled se see better as run lathe Dave?   
|
105°C sounds rather suspiciously (or perhaps not that suspiciously) like the lower temperature limit on most magnet wire used in motor coils. ? Gets hot, the enamel melts and the coil shorts out.? If you’ve spent enough time around motors or transformers you know the smell.? That 105°C is basically the maximum temperature for the motor coils, if you let it get anywhere near that you’re asking for trouble.? ? You can get magnet wire with better heat rating, up to about 250°C, but you don’t see that much.? That’s what the class of a motor means, better insulation.? Thoe old rule of if it’s too hot to touch, it’s too hot is well worth following. ? The other reason for keeping the heat down is the magnets.? Won’t bother the typical old-school mini-lathe motors, but newer motors (eg brushless) with neodymium magnets need to be kept cool as they start losing magnetism at around 80°C. ? Tony ? ?
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From: [email protected] <[email protected]> On Behalf Of davesmith1800 via groups.io
Sent: Wednesday, 1 May 2024 6:37 AM
To: [email protected]
Subject: [7x12MiniLathe] Mini lathe motor temperature? After researching of motors are 221°F [105°C] after that the life is shortened.?
The outside temperature is about? 60°F to 70°F? [15 to 20°C ] less the coil temperature.? So if outside is could be wend the coil is? 221°F [105°C] the outside is between? 151°F and 161°F [85 an 90°C].
On my gauge I set the red mark at 80°C and 105°C.?
If I see gets never red it time to let motor cool down and gives little to finish the cut.?
The Capillary is attached by HVAC Aluminum tape , max temperature is 145 °C at this point the motor is toast?
Dave?
Attachments:
|
Why should a minilathe motor be getting extremely hot in the first place? Mine never does. These machines aren't made for heavy use and cuts should be light. On the rare occasions that I've taken heavy cuts, I use a spindle crank.
Mike Taglieri?
105°C sounds rather suspiciously (or perhaps not that suspiciously) like the lower temperature limit on most magnet wire used in motor coils. ? Gets hot, the enamel melts and the coil shorts out.? If you’ve spent enough time around motors or transformers you know the smell.? That 105°C is basically the maximum temperature for the motor coils, if you let it get anywhere near that you’re asking for trouble.? ? You can get magnet wire with better heat rating, up to about 250°C, but you don’t see that much.? That’s what the class of a motor means, better insulation.? Thoe old rule of if it’s too hot to touch, it’s too hot is well worth following. ? The other reason for keeping the heat down is the magnets.? Won’t bother the typical old-school mini-lathe motors, but newer motors (eg brushless) with neodymium magnets need to be kept cool as they start losing magnetism at around 80°C. ? Tony ? ? ? After researching of motors are 221°F [105°C] after that the life is shortened.?
The outside temperature is about? 60°F to 70°F? [15 to 20°C ] less the coil temperature.? So if outside is could be wend the coil is? 221°F [105°C] the outside is between? 151°F and 161°F [85 an 90°C].
On my gauge I set the red mark at 80°C and 105°C.?
If I see gets never red it time to let motor cool down and gives little to finish the cut.?
The Capillary is attached by HVAC Aluminum tape , max temperature is 145 °C at this point the motor is toast?
Dave?
![]() ![]() ![]() Attachments:
|
Dear All, Many thanks for the motor info. David from across the Pond.
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On 3 May 2024, at 08:26, Miket_NYC <mctaglieri@...> wrote:
? Why should a minilathe motor be getting extremely hot in the first place? Mine never does. These machines aren't made for heavy use and cuts should be light. On the rare occasions that I've taken heavy cuts, I use a spindle crank.
Mike Taglieri? 105°C sounds rather suspiciously (or perhaps not that suspiciously) like the lower temperature limit on most magnet wire used in motor coils. ? Gets hot, the enamel melts and the coil shorts out.? If you’ve spent enough time around motors or transformers you know the smell.? That 105°C is basically the maximum temperature for the motor coils, if you let it get anywhere near that you’re asking for trouble.? ? You can get magnet wire with better heat rating, up to about 250°C, but you don’t see that much.? That’s what the class of a motor means, better insulation.? Thoe old rule of if it’s too hot to touch, it’s too hot is well worth following. ? The other reason for keeping the heat down is the magnets.? Won’t bother the typical old-school mini-lathe motors, but newer motors (eg brushless) with neodymium magnets need to be kept cool as they start losing magnetism at around 80°C. ? Tony ? ? ? After researching of motors are 221°F [105°C] after that the life is shortened.?
The outside temperature is about? 60°F to 70°F? [15 to 20°C ] less the coil temperature.? So if outside is could be wend the coil is? 221°F [105°C] the outside is between? 151°F and 161°F [85 an 90°C].
On my gauge I set the red mark at 80°C and 105°C.?
If I see gets never red it time to let motor cool down and gives little to finish the cut.?
The Capillary is attached by HVAC Aluminum tape , max temperature is 145 °C at this point the motor is toast?
Dave?
![]() ![]() ![]() Attachments:
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Dave, I am wondering.... Have you been running the motor at less than full speed? The cooling on these is typically based on the motor running at full speed so the fan can move enough air to maintain somewhat reasonable cooling. If you find you are running the lathe slower then I would recommend either an increased reduction belt drive (so the motor can run faster whilst keeping the spindle speed lower) and/or a separate cooling fan for the motor.?
On my first heavily modified mini I added a cover to the rear of the motor and attached some light flexible hose (Hoover vac hose) that is attached to a small squirrel cage blower with a bit of filter media on the blower inlet. This keeps the motor cooler and also keeps swarf from being taken in the motor.
Just my thoughts, Cheers
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I was going add a fan in November.? After thinking about the heat I need to know what heat is and someway to know if cooling fail.?
Also you do all your machining at 2,000 rpm.?
?I even thinking of indicator light.?
I need to know before anything happens like I do on my truck.?
Dave?
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On Fri, May 3, 2024 at 07:51 AM, ram50v8efi wrote:
Dave, I am wondering.... Have you been running the motor at less than full speed? The cooling on these is typically based on the motor running at full speed so the fan can move enough air to maintain somewhat reasonable cooling. If you find you are running the lathe slower then I would recommend either an increased reduction belt drive (so the motor can run faster whilst keeping the spindle speed lower) and/or a separate cooling fan for the motor.?
On my first heavily modified mini I added a cover to the rear of the motor and attached some light flexible hose (Hoover vac hose) that is attached to a small squirrel cage blower with a bit of filter media on the blower inlet. This keeps the motor cooler and also keeps swarf from being taken in the motor.
Just my thoughts, Cheers
|
Your welcome.?
It is probably lesser problem if you know before the gets to hot.?
?
It some of problems I read about mini lathes for years.?
Dave?
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On Fri, May 3, 2024 at 01:04 AM, DAVID WILLIAMS wrote:
Dear All, Many thanks for the motor info. David from across the Pond.
?
On 3 May 2024, at 08:26, Miket_NYC <mctaglieri@...> wrote:
Why should a minilathe motor be getting extremely hot in the first place? Mine never does. These machines aren't made for heavy use and cuts should be light. On the rare occasions that I've taken heavy cuts, I use a spindle crank.
?
Mike Taglieri?
105°C sounds rather suspiciously (or perhaps not that suspiciously) like the lower temperature limit on most magnet wire used in motor coils.
?
Gets hot, the enamel melts and the coil shorts out.? If you’ve spent enough time around motors or transformers you know the smell.? That 105°C is basically the maximum temperature for the motor coils, if you let it get anywhere near that you’re asking for trouble.?
?
You can get magnet wire with better heat rating, up to about 250°C, but you don’t see that much.? That’s what the class of a motor means, better insulation.? Thoe old rule of if it’s too hot to touch, it’s too hot is well worth following.
?
The other reason for keeping the heat down is the magnets.? Won’t bother the typical old-school mini-lathe motors, but newer motors (eg brushless) with neodymium magnets need to be kept cool as they start losing magnetism at around 80°C.
?
Tony
?
?
?
After researching of motors are 221°F [105°C] after that the life is shortened.?
The outside temperature is about? 60°F to 70°F? [15 to 20°C ] less the coil temperature.? So if outside is could be wend the coil is? 221°F [105°C] the outside is between? 151°F and 161°F [85 an 90°C].
On my gauge I set the red mark at 80°C and 105°C.?
If I see gets never red it time to let motor cool down and gives little to finish the cut.?
The Capillary is attached by HVAC Aluminum tape , max temperature is 145 °C at this point the motor is toast?
Dave?
![]() ![]() ![]()
Attachments:
?
?
|
You right about taking heavy cuts at low speed on mini lathe. The gauge is on there so do not have problem.??
Have a photo of the (spindle crank)?
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On Fri, May 3, 2024 at 12:26 AM, Miket_NYC wrote:
Why should a minilathe motor be getting extremely hot in the first place? Mine never does. These machines aren't made for heavy use and cuts should be light. On the rare occasions that I've taken heavy cuts, I use a spindle crank.
?
Mike Taglieri?
105°C sounds rather suspiciously (or perhaps not that suspiciously) like the lower temperature limit on most magnet wire used in motor coils.
?
Gets hot, the enamel melts and the coil shorts out.? If you’ve spent enough time around motors or transformers you know the smell.? That 105°C is basically the maximum temperature for the motor coils, if you let it get anywhere near that you’re asking for trouble.?
?
You can get magnet wire with better heat rating, up to about 250°C, but you don’t see that much.? That’s what the class of a motor means, better insulation.? Thoe old rule of if it’s too hot to touch, it’s too hot is well worth following.
?
The other reason for keeping the heat down is the magnets.? Won’t bother the typical old-school mini-lathe motors, but newer motors (eg brushless) with neodymium magnets need to be kept cool as they start losing magnetism at around 80°C.
?
Tony
?
?
?
After researching of motors are 221°F [105°C] after that the life is shortened.?
The outside temperature is about? 60°F to 70°F? [15 to 20°C ] less the coil temperature.? So if outside is could be wend the coil is? 221°F [105°C] the outside is between? 151°F and 161°F [85 an 90°C].
On my gauge I set the red mark at 80°C and 105°C.?
If I see gets never red it time to let motor cool down and gives little to finish the cut.?
The Capillary is attached by HVAC Aluminum tape , max temperature is 145 °C at this point the motor is toast?
Dave?
![]() ![]() ![]()
Attachments:
|
Well it shouldn’t, but I’m not the one trying to measure it.? I don’t know what Dave thinks he’s measuring, but that 105°C he’s set as his upper limit (over boiling water temperature, by the way) is the point where the enamel on the armature coils starts failing. ? The case temperature is going to be a lot lower.? As said, if you can’t touch it it’s way too hot. ? Tony ? ? ?
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From: [email protected] <[email protected]> On Behalf Of Miket_NYC via groups.io
Sent: Friday, 3 May 2024 5:27 PM
To: [email protected]
Subject: Re: [7x12MiniLathe] Mini lathe motor temperature? Why should a minilathe motor be getting extremely hot in the first place? Mine never does. These machines aren't made for heavy use and cuts should be light. On the rare occasions that I've taken heavy cuts, I use a spindle crank. ? 105°C sounds rather suspiciously (or perhaps not that suspiciously) like the lower temperature limit on most magnet wire used in motor coils. ? Gets hot, the enamel melts and the coil shorts out.? If you’ve spent enough time around motors or transformers you know the smell.? That 105°C is basically the maximum temperature for the motor coils, if you let it get anywhere near that you’re asking for trouble.? ? You can get magnet wire with better heat rating, up to about 250°C, but you don’t see that much.? That’s what the class of a motor means, better insulation.? Thoe old rule of if it’s too hot to touch, it’s too hot is well worth following. ? The other reason for keeping the heat down is the magnets.? Won’t bother the typical old-school mini-lathe motors, but newer motors (eg brushless) with neodymium magnets need to be kept cool as they start losing magnetism at around 80°C. ? Tony ? ? ? After researching of motors are 221°F [105°C] after that the life is shortened.?
The outside temperature is about? 60°F to 70°F? [15 to 20°C ] less the coil temperature.? So if outside is could be wend the coil is? 221°F [105°C] the outside is between? 151°F and 161°F [85 an 90°C].
On my gauge I set the red mark at 80°C and 105°C.?
If I see gets never red it time to let motor cool down and gives little to finish the cut.?
The Capillary is attached by HVAC Aluminum tape , max temperature is 145 °C at this point the motor is toast?
Dave?
Attachments:
|
The 105° is class A motor Insulation witch most motor use.?
The temperature drops as pass to outside casing.?
After that I use 176°F [ 80°C] for outside case? max temperature just to be on safe side.?
Note Most could burn your had around 140°F to 145°F
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On Sun, May 5, 2024 at 10:38 AM, Tony Smith wrote:
Well it shouldn’t, but I’m not the one trying to measure it.? I don’t know what Dave thinks he’s measuring, but that 105°C he’s set as his upper limit (over boiling water temperature, by the way) is the point where the enamel on the armature coils starts failing.
?
The case temperature is going to be a lot lower.? As said, if you can’t touch it it’s way too hot.
?
Tony
?
?
?
?
Why should a minilathe motor be getting extremely hot in the first place? Mine never does. These machines aren't made for heavy use and cuts should be light. On the rare occasions that I've taken heavy cuts, I use a spindle crank.
?
105°C sounds rather suspiciously (or perhaps not that suspiciously) like the lower temperature limit on most magnet wire used in motor coils.
?
Gets hot, the enamel melts and the coil shorts out.? If you’ve spent enough time around motors or transformers you know the smell.? That 105°C is basically the maximum temperature for the motor coils, if you let it get anywhere near that you’re asking for trouble.?
?
You can get magnet wire with better heat rating, up to about 250°C, but you don’t see that much.? That’s what the class of a motor means, better insulation.? Thoe old rule of if it’s too hot to touch, it’s too hot is well worth following.
?
The other reason for keeping the heat down is the magnets.? Won’t bother the typical old-school mini-lathe motors, but newer motors (eg brushless) with neodymium magnets need to be kept cool as they start losing magnetism at around 80°C.
?
Tony
?
?
?
After researching of motors are 221°F [105°C] after that the life is shortened.?
The outside temperature is about? 60°F to 70°F? [15 to 20°C ] less the coil temperature.? So if outside is could be wend the coil is? 221°F [105°C] the outside is between? 151°F and 161°F [85 an 90°C].
On my gauge I set the red mark at 80°C and 105°C.?
If I see gets never red it time to let motor cool down and gives little to finish the cut.?
The Capillary is attached by HVAC Aluminum tape , max temperature is 145 °C at this point the motor is toast?
Dave?
Attachments:
|
Here is max temperature from Baldor to last 20,000 hours. Remember this a Chinese motor could be a little less. Most motors under 100 hp use class A
Temperature (°C)
Maximum Winding
Temperature (Tmax)(°C)
A 105
B 130
F? 155
H 180
?
|
Those are not operating temperatures, they are MAXIMUM temperatures.? You want to be as far away from them as possible. ? If your casing is 80 degrees then your armature is far hotter than that. ? You can run your motor for 20,000 hour OR at 105°C, you cannot do both.? Read the spec sheet, it will derate the motor life based on temperature. ? For example run capacitors are rated at about 80 degrees, but again that’s the MAXIMIUM, you will kill your motor very quickly doing that.? For electronics the rule is for every 10 degrees Celsius rise the life expectancy halves.? Conversely dropping 10 degrees doubles the life span. ? Generally anything above 50 degrees makes a lot of people unhappy, 80 degrees would make them very unhappy. ? Tony ? ? ?
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From: [email protected] <[email protected]> On Behalf Of davesmith1800 via groups.io
Sent: Monday, 6 May 2024 5:48 AM
To: [email protected]
Subject: Re: [7x12MiniLathe] Mini lathe motor temperature? Here is max temperature from Baldor to last 20,000 hours.
Remember this a Chinese motor could be a little less.
Most motors under 100 hp use class A
|
Here's a pic of the motor that goes on my mini lathe.? Looks like
it's rated class E, which is 120 C per a wikipedia article.?
Stan
On 5/5/24 14:48, davesmith1800 wrote:
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Here is max temperature from Baldor to last 20,000 hours.
Remember this a Chinese motor could be a little less.
Most motors under 100 hp use class A
Temperature (°C)
Maximum Winding
Temperature (Tmax)(°C)
A 105
B 130
F? 155
H 180
?
|
I am looking for temperature be for smoke.?
I can only go by what in print.
I hope motor stays cool.
The? ambient used is either 40°C or 45°C? plus 60°C for motor.?
It all for longer life.?
Dave?
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On Sun, May 5, 2024 at 01:18 PM, Tony Smith wrote:
Those are not operating temperatures, they are MAXIMUM temperatures.? You want to be as far away from them as possible.
?
If your casing is 80 degrees then your armature is far hotter than that.
?
You can run your motor for 20,000 hour OR at 105°C, you cannot do both.? Read the spec sheet, it will derate the motor life based on temperature.
?
For example run capacitors are rated at about 80 degrees, but again that’s the MAXIMIUM, you will kill your motor very quickly doing that.? For electronics the rule is for every 10 degrees Celsius rise the life expectancy halves.? Conversely dropping 10 degrees doubles the life span.
?
Generally anything above 50 degrees makes a lot of people unhappy, 80 degrees would make them very unhappy.
?
Tony
?
?
?
?
Here is max temperature from Baldor to last 20,000 hours.
Remember this a Chinese motor could be a little less.
Most motors under 100 hp use class A
|
davesmith1800
ram50v8efi
