Adjusting appliance temps w/ no rheostat
 

OK all you home-handypersons, mechanical geniuses and electrical
wiring experts, have i got a question for you!

I got a new yogurt maker at a yard sale (lady had a failed
kitchen store business, it was brand new in the box sealed
etc.) First batch came out grainy (probably my fault)
so I made the second batch under closer observation.

Finished product was just over 130 degrees, which is
the high end for yogurt cultures.

Is there some way i can build a temperature control into
the electric wire to reduce the temperature, or do I need
to count this up to the usual yard sale failure?

maxine in ri, soldering iron at the ready

Adjusting appliance temps w/ no rheostat
 

maxine in ri > wrote:

>OK all you home-handypersons, mechanical geniuses and electrical
>wiring experts, have i got a question for you!
>
>I got a new yogurt maker at a yard sale (lady had a failed
>kitchen store business, it was brand new in the box sealed
>etc.) First batch came out grainy (probably my fault)
>so I made the second batch under closer observation.
>
>Finished product was just over 130 degrees, which is
>the high end for yogurt cultures.
>
>Is there some way i can build a temperature control into
>the electric wire to reduce the temperature, or do I need
>to count this up to the usual yard sale failure?
>
>maxine in ri, soldering iron at the ready

Sure. Although the classy way would be to use a rheostat or variable
autotransformer, but can guesstimate the value (in ohms) of
a fixed resistor to wire in series with the unit as follows:

R = ((130 - T)/(T - 70)) * (14400 / W)

where W is the actual wattage of the unit (which is probably a value
somewhat lower than its rated wattage), 130 is the observed
temperature now, 70 is the ambient temperature, T is the desired
temperature, and 14400 is the square of the line voltage.

So for example, let's say the unit is rated at 100 watts. Probably,
it consumes 90 watts, and you want the temperature to be 120
instead. In this case you need a 32 ohm series resistor. It better
be rated at 15 watts or more (in this example).

(Of course don't do this unless you're confident you can do
a safe job of wiring it up and insulating it and protecting
it from any mechanical trauma. Having a second person check your
work is always a good idea. Etc.)

Steve

Adjusting appliance temps w/ no rheostat
 

Steve wrote on Thu, 26 Jun 2008 17:23:26 +0000 (UTC):

>> OK all you home-handypersons, mechanical geniuses and
>> electrical wiring experts, have i got a question for you!
>>
>> I got a new yogurt maker at a yard sale (lady had a failed
>> kitchen store business, it was brand new in the box sealed
>> etc.) First batch came out grainy (probably my fault)
>> so I made the second batch under closer observation.
>>
>> Finished product was just over 130 degrees, which is
>> the high end for yogurt cultures.
>>
>> Is there some way i can build a temperature control into
>> the electric wire to reduce the temperature, or do I need
>> to count this up to the usual yard sale failure?
>>
>> maxine in ri, soldering iron at the ready

> Sure. Although the classy way would be to use a rheostat or
> variable autotransformer, but can guesstimate the value (in
>

It depends a lot on the design but you can be quite low-tech! If the
yoghurt is made in a removable container, you could put some sort of
insulation like cardboard below the pot. We used to do this quite a lot
when using a warming tray and in this case the insulation was a
dishtowel!
--

James Silverton
Potomac, Maryland

E-mail, with obvious alterations: not.jim.silverton.at.verizon.not

Adjusting appliance temps w/ no rheostat
 

Adjusting appliance temps w/ no rheostat
 

James Silverton <not.jim.silverton.at.verizon.not> wrote:

>It depends a lot on the design but you can be quite low-tech! If the
>yoghurt is made in a removable container, you could put some sort of
>insulation like cardboard below the pot. We used to do this quite a lot
>when using a warming tray and in this case the insulation was a
>dishtowel!

Yet another possibility is to set the yogurt maker somewhere where
the ambient temperature is lower.


Steve

Adjusting appliance temps w/ no rheostat
 

On Jun 26, 1:41 pm, (Steve Pope) wrote:
> James Silverton <not.jim.silverton.at.verizon.not> wrote:
> >It depends a lot on the design but you can be quite low-tech! If the
> >yoghurt is made in a removable container, you could put some sort of
> >insulation like cardboard below the pot. We used to do this quite a lot
> >when using a warming tray and in this case the insulation was a
> >dishtowel!
>
> Yet another possibility is to set the yogurt maker somewhere where
> the ambient temperature is lower.
>
> Steve

You mean like outside in an Alaskan winter? ;-)

I've got a funny feeling that the heating element's strength varies
between the sections that hold each of the 8 cups, since the first one
I measured was 130.5 and the second was closer to 120 (it was 5am and
I was not retaining all these numbers)
so I might have to consider something compromised between James', and
Steve/Alan's recommendations.

Plenty of time, since I'm mom-sitting this weekend.

maxine

Adjusting appliance temps w/ no rheostat
 

On Jun 26, 12:26�pm, maxine in ri > wrote:
> OK all you home-handypersons, mechanical geniuses and electrical
> wiring experts, have i got a question for you!
>
> I got a new yogurt maker at a yard sale (lady had a failed
> kitchen store business, it was brand new in the box sealed
> etc.) �First batch came out grainy (probably my fault)
> so I made the second batch under closer observation.
>
> Finished product was just over 130 degrees, which is
> the high end for yogurt cultures.
>
> Is there some way i can build a temperature control into
> the electric wire to reduce the temperature, or do I need
> to count this up to the usual yard sale failure?
>
> maxine in ri, soldering iron at the ready

It's no big deal to install a potentiometer into the unit (should fit
neatly into the chassis right next to the on/off switch)... probably
cost less than $5 for parts... bring that puppy down to your nearest
Radio Shack, they will sell you the parts and advise you for free.

http://tinyurl.com/43k5j9

http://www.radioshack.com/search/ind... iometers&sr=1

---

Adjusting appliance temps w/ no rheostat
 

Sheldon > wrote in news:7d1ead24-81d7-4e0f-8b1f-
:

> http://tinyurl.com/43k5j9

err Sheldon the rated power for this is 0.5 watts...not suitible for
kitchen appliances; fine for speakers though...good chance the yogurt maker
is rated over 500 watts. Can you say poof in the first usage.

--

The house of the burning beet-Alan

Adjusting appliance temps w/ no rheostat
 

On Thu 26 Jun 2008 11:45:50a, hahabogus told us...

> Sheldon > wrote in news:7d1ead24-81d7-4e0f-8b1f-
> :
>
>> http://tinyurl.com/43k5j9
>
> err Sheldon the rated power for this is 0.5 watts...not suitible for
> kitchen appliances; fine for speakers though...good chance the yogurt
> maker is rated over 500 watts. Can you say poof in the first usage.
>

Many yogurt makers use relatively low wattage.

http://www.healthgoods.com/shopping/...omparison_Char
t.htm

--
Wayne Boatwright
-------------------------------------------
Thursday, 06(VI)/26(XXVI)/08(MMVIII)
-------------------------------------------
-------------------------------------------
A new standard in obfuscation,
ambiguity, & equivocation.
-------------------------------------------

Adjusting appliance temps w/ no rheostat
 

On Jun 26, 2:45�pm, hahabogus > wrote:
> Sheldon > wrote in news:7d1ead24-81d7-4e0f-8b1f-
> :
>
> >http://tinyurl.com/43k5j9
>
> err Sheldon the rated power for this is 0.5 watts...not suitible for
> kitchen appliances; fine for speakers though...good chance the yogurt maker
> is rated over 500 watts. Can you say poof in the first usage.

Err, there was more than one on that page, and it would have been easy
to search further (why didn't you do that).... I only supplied the URL
at all in case the poster had no knowlege of what's a Radio Shack.
That's why I said to bring that puppy along... Radio Shack will sell
you the correct hardware and will offer free advice. I've always
found that there is someone at any Radio Shack that is very
knowlegeable and helpful. Helping the little guy with electronics
projects is the cornerstone of Radio Shack. There's a Radio Shack in
most every neighborhood so no one has to travel very far... that's the
very first place I go for any ald all electronics related issues...
need a new rechargeable battery for a Sony cordless phone, go to Radio
Shack, they'll have it in stock so no waiting and it'll cost far less
than directly from Sony.

http://www.radioshackcorporation.com/history.html

---

Adjusting appliance temps w/ no rheostat
 

In article >, says...
> maxine in ri > wrote:
>
> >OK all you home-handypersons, mechanical geniuses and electrical
> >wiring experts, have i got a question for you!
> >
> >I got a new yogurt maker at a yard sale (lady had a failed
> >kitchen store business, it was brand new in the box sealed
> >etc.) First batch came out grainy (probably my fault)
> >so I made the second batch under closer observation.
> >
> >Finished product was just over 130 degrees, which is
> >the high end for yogurt cultures.
> >
> >Is there some way i can build a temperature control into
> >the electric wire to reduce the temperature, or do I need
> >to count this up to the usual yard sale failure?
> >
> >maxine in ri, soldering iron at the ready
>
> Sure. Although the classy way would be to use a rheostat or variable
> autotransformer, but can guesstimate the value (in ohms) of
> a fixed resistor to wire in series with the unit as follows:
>
> R = ((130 - T)/(T - 70)) * (14400 / W)
>
> where W is the actual wattage of the unit (which is probably a value
> somewhat lower than its rated wattage), 130 is the observed
> temperature now, 70 is the ambient temperature, T is the desired
> temperature, and 14400 is the square of the line voltage.
>
> So for example, let's say the unit is rated at 100 watts. Probably,
> it consumes 90 watts, and you want the temperature to be 120
> instead. In this case you need a 32 ohm series resistor. It better
> be rated at 15 watts or more (in this example).
>
> (Of course don't do this unless you're confident you can do
> a safe job of wiring it up and insulating it and protecting
> it from any mechanical trauma. Having a second person check your
> work is always a good idea. Etc.)
>
> Steve
>

If I may, R = ((130-T)/(T-70)) *(V^2 / W) since 120V isn't normal in
some places.

For example for me I'd have to do R = ((130-T)/(T-70)) * (125^2 / W)

I've measured it, and it's definitely 125V service where I live.

Adjusting appliance temps w/ no rheostat
 

T > wrote:

>In article >, says...


>> R = ((130 - T)/(T - 70)) * (14400 / W)

>> where W is the actual wattage of the unit (which is probably a value
>> somewhat lower than its rated wattage), 130 is the observed
>> temperature now, 70 is the ambient temperature, T is the desired
>> temperature, and 14400 is the square of the line voltage.

>If I may, R = ((130-T)/(T-70)) *(V^2 / W) since 120V isn't normal in
>some places.
>
>For example for me I'd have to do R = ((130-T)/(T-70)) * (125^2 / W)
>
>I've measured it, and it's definitely 125V service where I live.

Of course. Neither is 70 degrees the ambient temperature
everywhere.

But the biggest unknown is the value of W, if you don't have
a multimeter. Hence my use of the term "guestimate".


Steve

Adjusting appliance temps w/ no rheostat
 

"maxine in ri" > wrote in message
...
> OK all you home-handypersons, mechanical geniuses and electrical
> wiring experts, have i got a question for you!
>
> I got a new yogurt maker at a yard sale (lady had a failed
> kitchen store business, it was brand new in the box sealed
> etc.) First batch came out grainy (probably my fault)
> so I made the second batch under closer observation.
>
> Finished product was just over 130 degrees, which is
> the high end for yogurt cultures.
>
> Is there some way i can build a temperature control into
> the electric wire to reduce the temperature, or do I need
> to count this up to the usual yard sale failure?
>
> maxine in ri, soldering iron at the ready

Adding a temp control to the wire would require a temp sensor probe going
into the area that heats the yogurt. That would not be so practical --
however you could splice in a heavy duty dimmer switch, such as for a
ceiling fan (the kind you replace a light switch with) and you could use
that to adjust the heat -- all you would need to do then was heat some water
at varied settings and measure the temp with a thermometer until you find
the temp you want, then just leave it at that setting. Don't use a dimmer
that is only for lights, as that would be too small current -- one for a
fan (motor) would be OK for something that only warms to 130°.

If you have a permanent place for the yogurt maker, you could simply splice
the dimmer switch into the wires by twisting them together and screwing on
those splice caps (same as electricians do with ceiling fans and lights). If
you plan to move it around a lot you would want to solder the connections or
tape them securely, or do both.


pflu

Adjusting appliance temps w/ no rheostat
 

Phluge wrote:

> Adding a temp control to the wire would require a temp sensor probe going
> into the area that heats the yogurt. That would not be so practical --
> however you could splice in a heavy duty dimmer switch

> Don't use a dimmer
> that is only for lights, as that would be too small current -- one for a
> fan (motor) would be OK for something that only warms to 130°.
> pflu

I definitely do not recommend using a fan speed control. They're
designed for inductive loads, and are at least overkill, and may not
work right at all. Almost any lamp dimmer is rated for more than the 100
Watts *max* a yogurt maker might run...

Dave

Adjusting appliance temps w/ no rheostat
 

Dave Bell > wrote:

>Phluge wrote:

>> Adding a temp control to the wire would require a temp sensor probe going
>> into the area that heats the yogurt. That would not be so practical --
>> however you could splice in a heavy duty dimmer switch

>> Don't use a dimmer
>> that is only for lights, as that would be too small current -- one for a
>> fan (motor) would be OK for something that only warms to 130°.
>> pflu

>I definitely do not recommend using a fan speed control. They're
>designed for inductive loads, and are at least overkill, and may not
>work right at all. Almost any lamp dimmer is rated for more than the 100
>Watts *max* a yogurt maker might run...

I agree with Dave. The fixed heating element in a yogurt
maker is a resistive load, more or less like an incandescent
bulb. A light dimmer should work fine.

Steve

Adjusting appliance temps w/ no rheostat
 

For simplicity, I like the light-dimmer idea. It's true that, to a
light dimmer, a heating element looks like a group of lamp bulbs.
Therefore, it should work just fine.

At Home Depot, the largest, readily-available dimmer will handle about
a 600-Watt load. Although you didn't state what the wattage of the
device is, if the nameplate say 600 Watts or less, thad HD dimmer will
do the job!

I suggest that you buy a dimmer with a rotary control—not a slider.
The rotary control is easier to manage and remember (for example, it's
easy to change from two o'clock to four or five on the rotary
control—a little difficult on the slide control.

The HD clerk can tell you what you need once you explain your problem.
If you're confused, come back here and we'll help you.










On Thu, 26 Jun 2008 09:26:10 -0700 (PDT), maxine in ri
> wrote:

>OK all you home-handypersons, mechanical geniuses and electrical
>wiring experts, have i got a question for you!
>
>I got a new yogurt maker at a yard sale (lady had a failed
>kitchen store business, it was brand new in the box sealed
>etc.) First batch came out grainy (probably my fault)
>so I made the second batch under closer observation.
>
>Finished product was just over 130 degrees, which is
>the high end for yogurt cultures.
>
>Is there some way i can build a temperature control into
>the electric wire to reduce the temperature, or do I need
>to count this up to the usual yard sale failure?
>
>maxine in ri, soldering iron at the ready