My copy isn't handy so I can't confirm this, but I think there's a
section on electric motors and their acceptable temperature rise in
Machinery's Handbook.
Mike Taglieri miket--nyc@...
Everyone has his reasons.
- Jean Renoir "The Rules of the Game"
On Sat, 10 Mar 2007 09:22:51 -0800 (PST) Druid Noibn
<druid_noibn@...> writes:
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Show quoted text
Hi All,
I thought it might be better to continue the thread - I do not
expect much will be said on this item.
I posted the temp rise on the HF 8x12-14 stock lathe motor with
pulleys and gears engaged but no cutting. The next step was to see
what the unloaded temp rise was. The belts were removed but the
stock pulley was left on. The motor had unobstructed airflow and
should be considered ???new.??? The ambient temp was 61.2F (16.2C).
05 min. ??? 12.1F (6.7C) rise
10 min. ??? 25.0F (13.9C)
15 min. ??? 35.6F (19.8C)
20 min. ??? 42.4F (23.6C)
30 min. ??? 53.0F (29.4C)
40 min. ??? 58.9F (32.7C)
50 min. ??? 62.2F (34.6C)
60 min. ??? 64.3F (35.7C)
This listing, and the one previously posted, indicate that the
motor runs a tad on the hot side although within typical
specifications (I don???t have the data sheet on the motor). The
tests were run on a continuously running motor which might be a
little unusual for most applications.
Again, this is just a little information for those who might wish
it.
Take care,
DBN
Druid Noibn <druid_noibn@...> wrote:
Hi Ed,
Point well taken.
I routinely use the hand-contact and counting rule and surprisingly
it is rather accurate. However, without doubt, the motor is running
on the hot side - of course, I am spolied by U.S. built motors,
transformers, etc... When I worked for a German-based company some
years ago, we replaced transformers and power diodes as often as one
replaced fuses. Several reported that the ratings placed on the
motors from China are at best suspicious or as some stated,
pararphrased, China must have small horses. Nonetheless, if time
permits, I'll run an unloaded test this weekend.
Thanks,
DBN
Ed Boysun <boysungran@...> wrote:
That really doesn't seem all that far out of line, to me. When being
run
continously, most motors will be nearly hot to the touch. Generally,
if
you can place your hand on them and count to 2, without being
burned,
nothing will be hurt in the motor. I guess I should really check
some of
my larger ones with an IR temp gun after they have run for a couple
hours, but I'd be surprised if they didn't run at least that warm.
Just looked at the plate on one of my water pump motors. That one
is
thermally protected for 40C above ambient.
Ed B
--- In 7x12minilathe@..., "druid_noibn"
<druid_noibn@...>
wrote:
Hi All,
For those who might find it "interesting" ??? I noticed the motor
of
the HF 8x12-14 was a tad warm and thought a check was in order.
With a motor and ambient temp of 65F the lathe was turned on ??? no
metal turning. The probe was located on the upper part of the
motor
housing, between the motor body and the junction box.
Without noting all of the readings, in the course of:
13 minutes ??? temp rise 39.3F;
30 minutes ??? 49.7F;
46 minutes ??? 58.1F;
63 minutes ??? 63F ??? shut-down motor
66 minutes ??? 65.7F
I didn't run the motor unloaded yet.
So the motor runs hot - an auxiliary fan might be in order.
Take care,
DBN
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