HomeRoast Digest


Topic: DC motor of WBII (13 msgs / 306 lines)
1) From: AlChemist John
I was experimenting with a WBII this morning.  I ripped it apart for its 
motor, wired it up to the plug, plugged it in and pop went my 20 amp 
circuit breaker.  I know there is a small aux heater to despeed the motor 
some, but I figured for a test run, it would be fine fan only.  Did I kill 
one of the diodes or the motor by not wiring it in also?  The first time I 
plugged it in, the motor started for a millisecond, arced the plug and 
tripped the breaker.  The next time, no fan, just arc and trip.  A third 
time I plugged in a 4.5 amp drill to the same outlet, ran it and then 
plugged in the fan, trip.  It is like I am short circuiting, but there are 
only two wires.  What am I missing please?
--
John Nanci 
AlChemist at large
Zen Roasting and Blending by Gestalthttp://www.dreamsandbones.net/blog/

2) From: Ken Mary
<Snip>
Probably both. You put 120v into something designed for 25v so something had
to give. The motor resistor creates a voltage drop across the motor/diode
circuit of about 20 to 25 volts. To operate the fan without the resistor,
you will need a 25v transformer.
--

3) From: Lowe, David
It's a 20 volt DC motor, with diodes on the back to make the AC into DC. =
I am sure you blew something. I run my WBII motor from the 25V side of a =
Radio Shack transformer, but 120V would be way high. You can get =
replacement diodes from Radio Shack, but if the motor is blown...:-( If =
you can easily find more thrift store WBII's (I can find them easily and =
cheaply) it might not even be worth the price of the diodes to check the =
motor.
Dave Lowe

4) From: Jim Schulman
On 4 Dec 2003 at 6:54, AlChemist John wrote:
<Snip>
apart
<Snip>
The DC motor (same in the WBII, WEPII, and FR) can only take 
about 25 volts. The drop down resistor in these units typically 
takes it down to around 14 to 18 volts. At 25 volt start ups, my 
FRs have lasted through at least a year's worth of roasts (250 
or so)
30 volts will slowly blow the diodes and short out the coils, 
with the usual smoke, sizzle, and tripped breaker. 110Volts will 
do it a lot quicker.
Jim

5) From: AlChemist John
Sometime around 14:41 12/4/2003, Jim Schulman typed:
<Snip>
That is the extra "heater coil"  that is wired in I assume.  Is it an 
actually heater coil (looks just like the other one) or resistor or is this 
one and the same no matter?
<Snip>
:-)
Upon further inspection in new light, on diode is black and crispy.  I now 
have two new ones for a whole $0.50 total.  Was not even worth replacing 
the diodes.
<Snip>
--
John Nanci 
AlChemist at large
Zen Roasting and Blending by Gestalthttp://www.dreamsandbones.net/blog/

6) From: Johnny Kent

7) From: Jim Schulman
On 5 Dec 2003 at 5:24, AlChemist John wrote:
<Snip>
Makes no difference. The FR has a ceramic case resistor that 
puts out just as much heat. The extra coil is a more elegant 
(i.e. cheaper) solution, since they're already setup for heating 
coil wire.
For the dual voltage hack: parallel the two coils for the heat 
circuit, and run the fan from a variable 25 volt source ( a 
stepdown transformer plus dimmer is cheapest)
Jim

8) From: AlChemist John
Sometime around 10:53 12/5/2003, Johnny Kent typed:
<Snip>
Interesting.  The one I have does not look like that exactly.  It only has 
coil around the out side, wired in two pieces.  The short piece corresponds 
to the inner coil of the picture shown, wiring wise.  No matter really.
<Snip>
--
John Nanci 
AlChemist at large
Zen Roasting and Blending by Gestalthttp://www.dreamsandbones.net/blog/

9) From: Ken Mary
<Snip>
Well, yes matter really. If your popper has a coil wired similar to the
Proctor Silex poppers, then the motor "resistor" is a part of the heater
coil and functions as a potentiometer or voltage divider. This design cannot
be wired with a simple heater switch, since the heater and "resistor" must
work together to provide the 20 volts. Are you sure you have a WB II? Maybe
it was repaired with a Proctor Silex heater.
--

10) From: AlChemist John
Sorry, WBII like.  I think it was a pumper.  It does not matter in that I 
have moved on to actual WBII's.
Sometime around 07:22 12/6/2003, Ken Mary typed:
<Snip>
--
John Nanci 
AlChemist at large
Zen Roasting and Blending by Gestalthttp://www.dreamsandbones.net/blog/

11) From: Lowe, David
That is exactly how my WBII is set up, its simple and it works well. 
Dave Lowe

12) From: AlChemist John
So those that have a split heater and fan, does the heat put out by the 
small coil get too hot for a fan motor as input air?  My measure about 140 
F.  Does anyone know if that is too hot for most motors, like a WBI thermal 
fuse?
Sometime around 10:23 12/8/2003, Lowe, David typed:
<Snip>
--
John Nanci 
AlChemist at large
Zen Roasting and Blending by Gestalthttp://www.dreamsandbones.net/blog/

13) From: Lowe, David
I roasted from some time in February to around September this year on a =
single WBII that was modified that way with no problem. Probably did =
about 4-5 roasts a week during that time. I had other WBII's available, =
but wanted to see how it would hold up. No indication of problems, even =
when I resurrected it after my WB1 blew its thermal fuse.
Dave Lowe


HomeRoast Digest