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And now you also know one of the reasons why motors used in the lunar and Mars rovers, and in similar applications require so much engineering. ???When there is no atmosphere, you are left with only radiation to get rid of heat buildup.? Of course there is also the problem with it being so cold that bearings shrink and lubricants freeze, so the engineers have to add bearing heaters that utilize radioactive decay to keep parts from sticking. ?I suspect they also have similar problems with hydraulic motors. ? Jerry F. ?
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From: [email protected] [mailto:[email protected]] On Behalf Of BuffaloJohn
Sent: Wednesday, July 10, 2024 5:45 PM
To: [email protected]
Subject: Re: [7x12MiniLathe] OT Hot Hot Hot? ? On Wed, Jul 10, 2024 at 4:54?PM davesmith1800 via <davesmith1=[email protected]> wrote: If remember NEMA ia at sea leave I think at 40% humidity.
No, there is NO humidity, it is 40C which is 104F. Also, the first elevation is from 0m to 999m ?
So high you go less cooling.?
No, as you go higher, air is thinner and therefore you need more cooling I have different outside temperature most are 105°F max for maximum horse power. If go hot hotter you need reduce the horse power.
NEMA and IEC motors are rated in degrees C, not degrees F. As I wrote, Class A insulation is rated to 105C. As for HP, that may be a motor curve, but it is irrelevant to the maximum temperature rating of the motor. There is a Service Factor rating that is part of the spec, but that was not added to this discussion. Some motor are designed for higher temperature and altitude.??
This best use formula for air compressor and pump. Machine tools are variable horse power needs.?
Almost all tools are variable power needs, the more the tool works, the more HP is needed. There are places in America that is over 1,000 feet? witch can you trouble with over heating motors
Motors with a Class A rating will be good to 1000m (~3300ft). If you are not pushing the overall rating of the motor, even up to 3000m (~9900ft), the motor doesn't need to overheat.
Dave?
On Wed, Jul 10, 2024 at 03:06 PM, BuffaloJohn wrote:
Nope, that is not how it works. Per NEMA, the maximum ambient temp is 40C (104F). There is a required reduction for altitude? (up to 1000m 40C, up to 2000m 30C, up to 3000m 20C). The IEC ratings are similar - also with a 40C ambient maximum. Based on the motor insulation class (NEMA A,B,F,H), there are temperature limits - referred to as temperature rise based on a maximum 40C ambient (A - 105C, B - 130C, F - 155C, H - 180C)..? THIS IS REALLY IMPORTANT - the maximum value listed by class has a starting point of 40C maximum. For example a Class A insulation class would allow a maximum temperature of 105C so a change of 105-40 = 65C . If ambient is higher that 40C, you still only go to 105C max, you just get less delta T. So - if ambient is 50C, you still only get to to a maximum of 105C. If ambient is 70C, you only get to 105C. AND if you are higher altitude, you have to degrade the maximum temperature because the starting point (maximum ambient) is lower. So, at 2000m, maximum ambient is 30C and you get 65C delta T so your maximum temperature is 95C. You can read about it here: ? On Tue, Jul 9, 2024 at 10:51?AM davesmith1800 via <davesmith1=[email protected]> wrote: It is what motor companies say. There a lot goes to figuring heat transfer.?
It is only a simple way of figuring out the limits.?
Dave?
On Tue, Jul 9, 2024 at 09:16 AM, Chris Albertson wrote: You can’t add temparures like that.? It is not linear. Without going into the science, maybe an easy why to explain it is that the rate that heat moves depends on the difference in temperature. So as a motor changes temparture the cooling rate also changes. Most motor are rated on any machine tool is rated for the rize in temperature.?
So if shop at 80° and motor rated 120° rize.The motor temperature is 200°
Now with today's temperature where I live is 114° plus 120° so now the motor is 234°.
The late great in winter at 70° plus 100° the motor is running at 170°.?
Now in summer the motor or electronic could give you a problem?
Most over look the problems Global warming is doing on motors and electronics in mini lathes and Mills.?
Dave?
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Buffalo John
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Buffalo John
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?Most motors have? ambient temperature of 105°F [40°C] Now live a hotter location a reduced in horse power. Here simple clip on motors . It max winding temperature you watch for.? If look on internet you find a more complex formula too. But only 1 or 2,° different? Here is clip on motors. 
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On Jul 10, 2024, at 5:44?PM, BuffaloJohn via groups.io <johndurbetaki@...> wrote:
See responses below
On Wed, Jul 10, 2024 at 4:54?PM davesmith1800 via <davesmith1= [email protected]> wrote: If remember NEMA ia at sea leave I think at 40% humidity.
No, there is NO humidity, it is 40C which is 104F.
We feel humidity as making the heat worse because our bodies are cooled by evaporation. ?humidity slows down the evaporation process. ?But this does not apply to motors.
The more modern way to use a motor is to embed a tempature sensor into it and have the controller reduce the power so as not to overheat the motor. ? But years ago sensors and the computer needed would cost more than the motor. ?But today it costs almost nothing so “temperature throttling" is common. ?I think our minilathes are too old of a design for this. ?Maybe the ones with BLDC motors have this?
In any case this whole problem of brushes goes away with brushless motors. ? The other thing about those motors is they have maximum torque at zero RPM. ? If you must replace a motor, that is the way to go.
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A few months I add a temperature gauge to my lathe and the Calc on how down does a mini lathe motor gets.
If go on internet you all garbage formulas on this subject for just few degrees.? But electric hand book it is simple ambient temperature + motor rize = running temperature?
Then you look at the max insulation temperature.?
Most ambient temperature is set 105°F? ,[40°C]. Because of Global this temperature maybe increase.?
Air conditioner was in 1970's 120°F??
I will say I do not know anyone using a mini lathe over 100°F Most likely under 90°F so Global warming is not a problem.? But check AC temperature.?
FYI
I look at mini lathes back around 2004 I look at mini lathe for work in line boring.? So on truck it would bun at 114°F
Dave?
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On Thu, Jul 11, 2024 at 12:54 AM, Chris Albertson wrote:
On Jul 10, 2024, at 5:44?PM, BuffaloJohn via groups.io <johndurbetaki@...> wrote:
See responses below
On Wed, Jul 10, 2024 at 4:54?PM davesmith1800 via <davesmith1= [email protected]> wrote: If remember NEMA ia at sea leave I think at 40% humidity.
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No, there is NO humidity, it is 40C which is 104F.
?
We feel humidity as making the heat worse because our bodies are cooled by evaporation. ?humidity slows down the evaporation process. ?But this does not apply to motors.
?
The more modern way to use a motor is to embed a tempature sensor into it and have the controller reduce the power so as not to overheat the motor. ? But years ago sensors and the computer needed would cost more than the motor. ?But today it costs almost nothing so “temperature throttling" is common. ?I think our minilathes are too old of a design for this. ?Maybe the ones with BLDC motors have this?
?
In any case this whole problem of brushes goes away with brushless motors. ? The other thing about those motors is they have maximum torque at zero RPM. ? If you must replace a motor, that is the way to go.
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Using a mini lathe and other tools in 2004 most of time temperature of 105°F and maybe spikes to 108°.?
Today the temperature is over 108° and days to 113°F?
So odds of burning the mini lathe motor today is greater because of Global warming.??
But do not know any here Using a mini lathe over 90°F
Dave?
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Here calculations for mini lathe in ambient temperature 104°F? [40°C]?
Motor rize in temperature 60°C
Hot spot 5°C?
Total is 105°C?
Then check your insulation temperature along below you good shape.?
Now with global warming to 115°F [46°C]
ambient temperature 115°F? [46°C]?
Motor rize in temperature 60°C
Hot spot 5°C?
Total is 231°F? [111°C ]
Your insulation mat not hold up or short Motor life
Dave?
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I do at times but it's never long running stuff. A bit here and there. So I seriously doubt there would be any issues doing it that way. And it's not often. For sure I do more in the upper 80s so i don't think it bothers the motor much if it's a few degrees higher. Nothing I do is ever long running.
george
On Thursday, July 11, 2024 at 07:54:44 AM PDT, davesmith1800 <davesmith1@...> wrote:
Using a mini lathe and other tools in 2004 most of time temperature of 105°F and maybe spikes to 108°.?
Today the temperature is over 108° and days to 113°F?
So odds of burning the mini lathe motor today is greater because of Global warming.??
But do not know any here Using a mini lathe over 90°F
Dave?
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Intermittent operation may actually make the motor internals hotter than continuous running! With intermittent running, the motor's internal fan is stopped while the heat generated internally is still trying to travel to a cooler area without the fan helping it to flow. An easy fix is adding an external fan, which can also be arranged to cool the electronics at the same time.
Roy
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It more likely to do with air compressor sitting outside for shop air. The mini lathe should be in a cooler room. Maybe the AC keeping the you mini lathe and you cool
Dave?
On Thu, Jul 11, 2024 at 12:56 PM, gcvisalia@... wrote:
?
I do at times but it's never long running stuff. A bit here and there. So I seriously doubt there would be any issues doing it that way. And it's not often. For sure I do more in the upper 80s so i don't think it bothers the motor much if it's a few degrees higher. Nothing I do is ever long running.
?
george
?
On Thursday, July 11, 2024 at 07:54:44 AM PDT, davesmith1800 <davesmith1@...> wrote:
?
?
Using a mini lathe and other tools in 2004 most of time temperature of 105°F and maybe spikes to 108°.?
Today the temperature is over 108° and days to 113°F?
So odds of burning the mini lathe motor today is greater because of Global warming.??
But do not know any here Using a mini lathe over 90°F
Dave?
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Nope. Just a remodeled two car garage without insulation. No ac, just a small fan. Today at my house it was 114.
george
On Thursday, July 11, 2024 at 09:26:38 PM PDT, davesmith1800 <davesmith1@...> wrote:
It more likely to do with air compressor sitting outside for shop air. The mini lathe should be in a cooler room. Maybe the AC keeping the you mini lathe and you cool
Dave?
On Thu, Jul 11, 2024 at 12:56 PM, gcvisalia@... wrote:
?
I do at times but it's never long running stuff. A bit here and there. So I seriously doubt there would be any issues doing it that way. And it's not often. For sure I do more in the upper 80s so i don't think it bothers the motor much if it's a few degrees higher. Nothing I do is ever long running.
?
george
?
On Thursday, July 11, 2024 at 07:54:44 AM PDT, davesmith1800 <davesmith1@...> wrote:
?
?
Using a mini lathe and other tools in 2004 most of time temperature of 105°F and maybe spikes to 108°.?
Today the temperature is over 108° and days to 113°F?
So odds of burning the mini lathe motor today is greater because of Global warming.??
But do not know any here Using a mini lathe over 90°F
Dave?
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Possibly. But my running time may not produce the kind of dangerous heating that we think. I do mostly small stuff. My motor is also a brushless one.?
george
On Thursday, July 11, 2024 at 08:12:21 PM PDT, Roy via groups.io <roylowenthal@...> wrote:
Intermittent operation may actually make the motor internals hotter than continuous running! With intermittent running, the motor's internal fan is stopped while the heat generated internally is still trying to travel to a cooler area without the fan helping it to flow. An easy fix is adding an external fan, which can also be arranged to cool the electronics at the same time.
Roy
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The good news this heating of earth has happen before.? Last time was around 1905 it did get very cold in 1944.?
We have not broken any records from 1905.?
It is not ever x number of years it has to do with earth orbit and other things I for got.?
This what happened with ice age.?
I have not to the words G#%%# W#%^$$.?
The best violin was from had a 75 on a earth cool down.?
England had great wine grapes when had a global temperature increase.?
My grandparents live here in 1905 Fresno when 115°F and some parts of Valley got to 116°F. Back then thd call it G [b] [/b] in 1940's they call it G C.
FYI? both polar ice was hot too in earth history. All we are is in a up cycle
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davesmith1800