Mark,
I suggest you file a patent on a using an insulating material
that will melt and short shortly before a motor is damaged from
overheating.? By utilizing the circuit's over current protection,
this invention can provide reliable motor overheating protection
for about a cent's worth of insulation.
Once your patent is granted, you can file infringement claims on
all motor manufacturers with shoddy construction, thereby forcing
them to improve their build quality.? That will make you a hero!
(sarcasm aside, congrats on finding an easy fix!)
On 9/2/2023 3:10 AM, Hettie Chom wrote:
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Hi, a very good selution for your problem with a
satifying end.
A
few days ago I was cutting a small length of 1" square stock
with my bandsaw.? I supported the piece on a sacrificial strip
of aluminum to make sure it wouldn't tip down while being
sawn.? The sacrificial piece was a bit narrower than the stock
so I could grip it with the vise.? The mistake I made was to
turn the saw on and then I left for a "quick" errand.? But
that turned into a much longer interval -- so the saw was
unattended.? Well, when I finally came back the saw had
stopped, but that's because the cutoff piece had jammed the
saw.? Probably because the sacrificial piece prevented the saw
from immediately turning off.? The scrap got sucked into the
bearing guides and jammed.
I didn't smell a burnt odor coming from the motor and the
breaker for that outlet had tripped so I was hopeful that the
saw was OK, but that turned out to not be the case.? With
power restored and the jam cleared, the motor clearly was
dead.? My ohmmeter showed an open connection.? It wasn't the
switch which only left the motor as the location of the open
circuit.
I found that Harbor Freight claims to have replacement bandsaw
motors but they're about $150 so I thought it was worth my
time to see if I could fix the motor.? I found an online forum
where someone had repaired theirs by replacing a thermal
cutout located inside the motor housing so......maybe I might
get lucky.
I removed the motor and took off the end nearest the power
cord connection but unfortunately my model had no thermal
cutout.? Still no bad burnt odor and the windings looked OK so
I used my ohmmeter some more to see if I could locate the open
connection.? I had to remove the heat-shrink tubing from the
power cord-to-windings connections and noticed that the hot
and ground return wires were stuck together.? More examination
revealed that they were melted.? ?They had been tied very
tightly by some kind of string so when the motor got hot
enough to soften the insulation the wires came in contact,
blew out and tripped the breaker.
Long story short, I replaced the power cord connections,
re-assembled the motor and tested it.? It ran with no noises,
tripped breakers or any obvious complaint.
I got lucky and learned a lesson.? Don't walk away from a
running bandsaw.
