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Topic: WBI question (19 msgs / 324 lines)
1) From: AlChemist John
I have been rewiring a WB I and a WBII so that they both have on/off 
switches and independent heater switches.  Both had their thermostats 
adjusted (WBII ripped out) .  The WBII was a success and gives a nice 7-8 
min second crack.
The WBI WAS working well on the proto-wiring.  The fan came on with the 
main switch.  The heater came on when I flipped the other.  The heater was 
off if the main switch was off.  Well, I got everything hardwired, verified 
from my drawing and...nothing
Using a meter I have determined one of the two leads to the fan motor is 
not making a connection inside the motor.  I never touched this area.  Any 
thought what else could be wrong.  Does it sound like I need to get inside 
the motor (I really would rather not if possible) and check that lead.
I was really hoping to post a glowing hack report, instead,  Help please!!! :-(
--
John Nanci 
AlChemist at large
Roasting and Blending by Gestalt
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2) From: EskWIRED
<Snip>
How exactly did you determine that?  Might the lead itself have a problem,
like a broken solder joint where it meets the motor?
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3) From: AlChemist John
Sometime around 18:15 8/6/02, EskWIRED typed:
<Snip>
That is exactly what I mean.  Their is a continuous circuit until I reach 
the terminal end of one lead.  I just can not check that solder joint 
easily as it appears inside the motor.
--
John Nanci 
AlChemist at large
Roasting and Blending by Gestalt
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4) From: EskWIRED
<Snip>
Bummer.  If the break is inside the motor, I'd say you have some delicate
dissection ahead of you, followed by some coil (re)winding.
Can you possibly wiggle the wire with the power on, to try to find a break
somewhere in the wire before it hits the motor?  If you can find one, it
will be very easy to strip the wire back to the break and lengthen it with a
crimp connector.
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5) From: Dan Bollinger
<Snip>
John,  Before I respond, answer this: Do you mean you don't have a
continuous circuit between the two motor leads?  Dan
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6) From: Dick Heggs
AlChemist John!
There is a thermofuse in the blower motor of the WBI.  It is inside a
insulating fabric sleeve and held with a brass strip.  This is possibly
the cause of your problem.  It will blow if the motor is overheated.
Radio Shack usually has a replacement.  I have only had one blow and
that was one from a friend that allowed chaff to build up in the motor.
--
R.S. (Dick) Heggs
From the Okanagan Valley of Beautiful British Columbia
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7) From: Jeffrey A. Bertoia
Nice to see that you are still out there Dick!
jeff
Dick Heggs wrote:
<Snip>
-- 
Jeffrey A. Bertoia                      jbertoia
Slalom Services, Inc.                   www.SlalomServices.com
Telephone: +1 (810) 220 - 1174          Mobile: +1 (586) 854 - 7312
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8) From: AlChemist John
Sometime around 07:25 8/7/02, Dan Bollinger typed:
<Snip>
Yes, this is correct.
--
John Nanci 
AlChemist at large
Roasting and Blending by Gestalt
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9) From: AlChemist John
Sometime around 07:49 8/7/02, Dick Heggs typed:
<Snip>
I had a suspicion that that was what that was.  I wondered if it was the 
culprit but there is continuity between both sides of it.
Would that be the case if it had blown?
--
John Nanci 
AlChemist at large
Roasting and Blending by Gestalt
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10) From: Dan Bollinger
<Snip>
That's what I thought. There shouldn't be!  There should be a low resistance
not continuity (implies no resistance).  If you have an ohm meter, check it
for resistance as you turn the motor shaft.  Better yet, measure resistance
across oppossing commutators.  You should get a few ohms on each one.  Zero
reading means that coil is burnt out.  Contintuity means that coil is
shorted out. Also, check the brushes, the number one failure of universal
motors is worn brushes.  hope this helps.  Dan
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11) From: AlChemist John
Sometime around 04:48 8/8/02, Dan Bollinger typed:
<Snip>
OK, fair warning, I'm a chemist not an electrical "use proper term 
".  Please forgive me if I ask you to explain something you have already 
explained.
When I said there is continuity, what I mean by this is that I have  a 
feature ( don't know if a lot of meters have it) on my multi meter that 
gives an audible tone if a particular "circuit" is unbroken, i.e.  the 
leads of the probe touching, two ends of a wire.  What the motor gave me 
was a  tone from touching one terminal and virtually any metal piece of the 
motor except the other terminal.  The "other" terminal would not give any 
tones anywhere on the motor.
<Snip>
I will do that.
OK, it is about 80 ohms
Is this "low"?
<Snip>
What are commutators? Are these the 8 extensions on the shaft that rotate 
near the brushes.  If so they are also all about 80 ohms
<Snip>
<Snip>
Someone at work also suggested brushes.  What do I "check".  They "look" ok.
<Snip>
YES!  It gives me someplace to start (and may teach me something in the 
process) Thanks.
--
John Nanci 
AlChemist at large
Roasting and Blending by Gestalt
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12) From: Dan Bollinger
<Snip>
the
<Snip>
Yes, the tone reports continuity.  You should NOT be getting continuity
between the motor frame and one of the terminals.  There is a short
somewhere. :(
<Snip>
it
<Snip>
Yep.  Sounds right.
<Snip>
Yep, and this part of your motor (the rotor) checks out OK.
<Snip>
ok.
There should be enough of the brushes left that the brushes press against
the commutators. The spring should be applying a small force to keep them
there.  If the brushes are worn too low they cannot conduct electricity.
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13) From: AlChemist John
Sometime around 06:28 8/8/02, Dan Bollinger typed:
<Snip>
The key term there is "virtually".  My apologies, that was to 
ambiguous.  Actually the terminal to any of the housing (just checked it) 
has no tone nor ohms.  What I should have said was the terminal to any 
metal piece "that should be in the circuit" gave a tone.
The brushes again look ok and would seem fine since I am getting a 
resistance between the two.
I guess it is looking like that one lead is bad at some point.  I guess I 
will slit the insulation to check for breaks and otherwise get under the 
motor and see if I can find the solder connection.  Sound reasonable?
Thanks again.
--
John Nanci 
AlChemist at large
Roasting and Blending by Gestalt
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14) From: Dan Bollinger
<Snip>
John,  I think your motor is OK. Resistance between the terminals is a good
sign that your brushes are OK.  90% of the time an appliance fails because
of contacts.  Switches, wire connections, etc. Sounds like you are zeroing
in on the culprit. Dan
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15) From: Dick Heggs
Not the fuse then.  A blown fuse is like a broken wire.
John Alchemist wrote:
I had a suspicion that that was what that was.  I wondered if it was the
culprit but there is continuity between both sides of it.
Would that be the case if it had blown?
--
R.S. (Dick) Heggs
From the Okanagan Valley of Beautiful British Columbia
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16) From: AlChemist John
Sometime around 07:17 8/8/02, Dan Bollinger typed:
<Snip>
Well, I have zeroed in on the culprit and I am most unhappy as I am to 
blame.  It looks like when I slipped one of the times taking it apart I hit 
one of the outer wraps of wire and broke a wire.  I have not found the 
actual break yet but I have check ALL connections and  all are ok.  At some 
point I will rip the whole motor apart to see if I can find the break, but 
for the moment I goes onto the back burner until I find the time.
Great big sigh  :-(
Thanks for all the input folks.
--
John Nanci 
AlChemist at large
Roasting and Blending by Gestalt
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17) From: Dan Bollinger
John,  A break in the outer, stator windings?  I've never had any success
repairing windings. I'd suggest ordering an replacement motor or finding a
replacement on eBay.  Dan

18) From: AlChemist John
Sometime around 04:05 8/10/02, Dan Bollinger typed:
<Snip>
Yes, there.  Can you suggest where to get a very cheap (the whole popper 
was $2.00 remember) replacement motor?  Primarily I'm just going to keep my 
eye out for another WB1.
Nothing like a simple project :-}
--
John Nanci 
AlChemist at large
Roasting and Blending by Gestalt
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19) From: Dan Bollinger
John, Your best bet is a yard sale or thrift shop.  Dan
<Snip>
a
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my
<Snip>
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