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May 20th 2012:
Ever had a cheap
oscillating fan stop working? I had an HTF3110A
tower fan , and figured, "They cost thirty bucks, how
hard could it be to fix it?"
Materials:
Part no.
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Description
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QTY
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Price
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Source
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270-1322
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Thermal Fuse
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1
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$0.75
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Radio
Shack
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n/a
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12Ga butt
connectors
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about 6
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n/a
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local hardware
store
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n/a
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pop rivets (size
may vary)
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2
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n/a
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local hardware
store
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n/a
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Engine builders
lube
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n/a
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n/a
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local auto parts
store
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n/a
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WD-40
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n/a
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n/a
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local auto parts
store
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n/a
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Zip ties
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about 12
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n/a
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local hardware
store
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Tools:
- Wire Strippers
- Phillips head #1
- Flat head for
prying
- Soldering iron
- Butt connector
crimper
- Multimeter
- Drill and bits
Repair procedure:
- Remove 9 screws that hold the rear cover on:
- Remove the fan blades assembly by loosening a
locking screw at the base of the fan, connecting it to
the motor. Then, lift the fan assembly off the motor
shaft. The metal bracket holding the upper bearing on
the fan blades may bend abit, no big deal, bend it
back if needed:
- The motor is held in place by four screws on it's
flanges. They can be removed to pull out the motor.
Some wire restraints may also need to be removed here:
- The simple brushless A/C
induction motor (similar to a ceiling fan) has a
housing of two stamped sheet metal pieces, held
together by tabs built into themselves and folded
though holes in the other. The easiest way to get
inside is to drill them out:
- Pry the motor housing apart with a flat head:
- The rotor has seized and will not turn, probably due
to poor lubrication from the factory. This, I believe
to be the initial fault. I removed it from the upper
potion of the motor housing and cleaned it up with
some WD-40:
- I used the flat head again to remove the
stator from the lower motor housing. Note the wires I
clipped at the fan, but left their respective
connector on the wire they connected to. Since each
wire did not necessarily connect back to the same
color wire, leaving a small amount of the original
insulation kept me from having to label the wires:
At this point I also used a multimeter to check
continuity on all the wires. They grey wire had none.
It was connected to the thermal protection fuse in the
next step.
- After the rotor seized and stopped turning, the
coils heated up with no cooling, this caused the
thermal fuse to blow. This one appears to be rated at
115 degrees Celsius (239 Fahrenheit). Mine is not
exact but a suitable replacement at 129 degrees
Celsius (264 Fahrenheit) At this point I could
have just bypassed the fuse to make the motor spin,
but I don't like burning down my house. NEVER DEFEAT A SAFETY
INTERLOCK OR SYSTEM!
Bonus Question : Why does Google no longer convert C
to F for you? Instead of showing me the result I asked
for, Google just searched, found, and directed me to
an online converter.
- I cut the wax string holding the wires and coils
together so I could remove the insulating tube that
isolates the colored wires from their coil leads:
- Since the thermal fuse is heat sensitive, you must
be very careful when soldering it to the leads. I used
long leads and a keyring acted as a good heat sink:
- After soldering the fuse on, I slipped the little
insulator tubes back on the leads and used small zip
ties to secure everything. I did not have any waxy
string. Make sure you keep the new thermal fuse near
the coil so that it will blow when it gets hot:
- The next steps are all reassembly. It is the reverse
of the above, with a few minor differences. Such as
better lubricant:
- pop rivets to hold the motor together and butt
connectors are aready crimped on this side:
- Here the motor is remounted and wires are
reconnected. I used this time to clean the dust from
all the plastice parts:
- The motor spins freely and the covers are screwed
back on after the fan blades are installed. The fan
once again works great.
Thanks for making it this far. Be advised I am working
on getting a better camera, and that reading this page
about what I did in no way makes me qualified to train
you to be an expert in electrical, electronics,
electricity, or the basic use of tools and not eating
grease. This is all informational
only so others can see what I did. If you burn
down you house or hurt yourself or others in anyway, it's your fault, not mine.
Please send any feedback to me.
.
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