Homebrew_PCBs

The Ultrakeet super-fuser mods sounded interesting: https://ultrakeet.com.au/write-ups/superFuserV2

Especially since the Royal Sovereign CS-923 is of similar design and available for around $25 from Amazon. Problem is, the CS-923 has three thermostat switches instead of two, and Ultrakeet doesn't provide much technical information (or respond to emails). The 3 thermal switches are rated at 110, 120, and 140 deg. C and his modification is to replace one of the 2 switches in his Lowell unit with a new 160 deg. C switch to raise the operating temperature. Does anyone know which one should be replaced?

I think these switches have normally-closed contacts, but if the first one that opens breaks the flow of current (i.e. the lowest temperature), then what's the point of the others? (One of the two lower temp switches is selected by a rocker switch corresponding to 3 and 5 mil pouches). This might be a good solution for toner transfer, but simple as it is, I'm a little puzzled about how to increase the operating temp. Suggestions would be welcomed!

Bob

On Tue, 30 Apr 2013 18:53:39 -0000, you wrote:

>The Ultrakeet super-fuser mods sounded interesting: https://ultrakeet.com.au/write-ups/superFuserV2
>
>Especially since the Royal Sovereign CS-923 is of similar design and available for around $25 from Amazon. Problem is, the CS-923 has three thermostat switches instead of two, and Ultrakeet doesn't provide much technical information (or respond to emails). The 3 thermal switches are rated at 110, 120, and 140 deg. C and his modification is to replace one of the 2 switches in his Lowell unit with a new 160 deg. C switch to raise the operating temperature. Does anyone know which one should be replaced?

I'll guess the 140 degree one.

>
>I think these switches have normally-closed contacts, but if the first one that opens breaks the flow of current (i.e. the lowest temperature), then what's the point of the others? (One of the two lower temp switches is selected by a rocker switch corresponding to 3 and 5 mil pouches). This might be a good solution for toner transfer, but simple as it is, I'm a little puzzled about how to increase the operating temp. Suggestions would be welcomed!
>

The temperatures seem to be either 110 or 120 degrees selectable by
switch, with the 140 degree being an "OMG" switch to protect the
entire laminator. Just replacing the 140 with a 160 wouldn't help,
since the lower temp switches take precedence. I'd think you also
have to remove one of the lower temp switches (just take it out and
bypass it entirely, I'd think the 110 one. That way you have 120 and
160. If you want 140 and 160, then replace the 110 with the 160,
bypass the 110 position entirely, wire the 140 in place of the 120, so
you have:

1) in the 5 mil position, you have 140 degrees with a 160 safety.
2) in the 3 mil position, you have 160 degrees with no safety other
than that one switch.

May make sense to you to reverse the 3 and 5 mil position, so that 3
mil is the 140 and 5 mil is the 160 (only).

Harvey

>Bob

I've moded about 5 of the lowell/aldi laminators
as per ultrakeet.

There is a bimetalic and a thermal fuse.

The bimetalic is for normal opperation and
the fuse trips if something goes wrong and it
all gets too hot.

Does the royal sov. have the extra thermostat
instead of a fuse? Or is the 3rd thermostat
just in different spot?

Have you traced out the schematic and can
post for us?

--- In Homebrew_PCBs@yahoogroups.com, "w9ran" <w9ran@...> wrote:
>
> The Ultrakeet super-fuser mods sounded interesting: https://ultrakeet.com.au/write-ups/superFuserV2
>
> Especially since the Royal Sovereign CS-923 is of similar design and available for around $25 from Amazon. Problem is, the CS-923 has three thermostat switches instead of two, and Ultrakeet doesn't provide much technical information (or respond to emails). The 3 thermal switches are rated at 110, 120, and 140 deg. C and his modification is to replace one of the 2 switches in his Lowell unit with a new 160 deg. C switch to raise the operating temperature. Does anyone know which one should be replaced?
>
> I think these switches have normally-closed contacts, but if the first one that opens breaks the flow of current (i.e. the lowest temperature), then what's the point of the others? (One of the two lower temp switches is selected by a rocker switch corresponding to 3 and 5 mil pouches). This might be a good solution for toner transfer, but simple as it is, I'm a little puzzled about how to increase the operating temp. Suggestions would be welcomed!
>
> Bob
>

> Have you traced out the schematic and can post for us?

I have uploaded a copy of the wiring diagram into the Files Section under "Laminator Mods".

I'd appreciate comments from anyone who is interested in modifying this cheap (<$25) laminator that uses bimetal thermostat switches for temp control. Ultrakeet in OZ replaces the thermal protector (fuse) with a new 250 deg. one, and swaps a new 160 deg. thermostat for one of the existing ones. My question to the group was "which one" to replace, as the CS-923 has three of them instead of two as in the Ultrakeet example.

Here's how the laminator control system works: The heater elements (connected in series with the thermal fuse) are powered from either half-wave or full-wave rectified AC line voltage, depending on temperature. At power-up, both thermal switches are closed, which provides full-wave rectified voltage to appear across the heater element. Once the temp rises to either 115 or 125 deg and the low voltage thermostat opens, one rectifier will be disconnected and the heater will only see negative half-cycles, reducing the average voltage by about one-half. When the heat rises to the point where the 145 deg. thermostat finally opens, all power will be removed and the heater will begin to cool and the green LED will be off until the stat re-closes.

Thus in normal operation the temperature is controlled in the range of the selected lower-temperature stat and 145 deg. The behavior of this control loop is going to depend a lot on the thermal response of the heater-roller mass. If the temp were to drop below the threshold of the low-temp switch, it will close and again supply the higher average voltage to the heater to bring it quickly up to temp, but otherwise it seems that the 145 deg. thermostat will do most of the controlling. It's a pretty clever design, based on a few inexpensive parts.

So the answer seems to be to substitute the new 160 deg. stat for the 145 degree one, which will allow the laminator to reach a higher temperature before it shuts off. However, one could also replace one of the low-temp stats and thus reverse the function, so that the full voltage would be applied until the 145 stat opens, which would presumably maintain the temperature between 145 and 160 deg.

Thoughts? I guess its time to take some temperature measurements.

73, Bob W9RAN

I did a bit differently - did not replace existing thermostat, but added
another one, with a switch to choose between them. That way, laminator can
be used for original purposes too.
Even better way should be to add also the lower-temperature one, so the
half-power heating starts a bit later, otherwise it takes a very long time
to heat to 160C. But I did not have a small double-pole double-throw switch
handy at the moment...

On Mon, May 6, 2013 at 7:17 AM, w9ran <w9ran@...> wrote:

> **
>
>
>
>
> > Have you traced out the schematic and can post for us?
>
> I have uploaded a copy of the wiring diagram into the Files Section under
> "Laminator Mods".
>
> I'd appreciate comments from anyone who is interested in modifying this
> cheap (<$25) laminator that uses bimetal thermostat switches for temp
> control. Ultrakeet in OZ replaces the thermal protector (fuse) with a new
> 250 deg. one, and swaps a new 160 deg. thermostat for one of the existing
> ones. My question to the group was "which one" to replace, as the CS-923
> has three of them instead of two as in the Ultrakeet example.
>
> Here's how the laminator control system works: The heater elements
> (connected in series with the thermal fuse) are powered from either
> half-wave or full-wave rectified AC line voltage, depending on temperature.
> At power-up, both thermal switches are closed, which provides full-wave
> rectified voltage to appear across the heater element. Once the temp rises
> to either 115 or 125 deg and the low voltage thermostat opens, one
> rectifier will be disconnected and the heater will only see negative
> half-cycles, reducing the average voltage by about one-half. When the heat
> rises to the point where the 145 deg. thermostat finally opens, all power
> will be removed and the heater will begin to cool and the green LED will be
> off until the stat re-closes.
>
> Thus in normal operation the temperature is controlled in the range of the
> selected lower-temperature stat and 145 deg. The behavior of this control
> loop is going to depend a lot on the thermal response of the heater-roller
> mass. If the temp were to drop below the threshold of the low-temp switch,
> it will close and again supply the higher average voltage to the heater to
> bring it quickly up to temp, but otherwise it seems that the 145 deg.
> thermostat will do most of the controlling. It's a pretty clever design,
> based on a few inexpensive parts.
>
> So the answer seems to be to substitute the new 160 deg. stat for the 145
> degree one, which will allow the laminator to reach a higher temperature
> before it shuts off. However, one could also replace one of the low-temp
> stats and thus reverse the function, so that the full voltage would be
> applied until the 145 stat opens, which would presumably maintain the
> temperature between 145 and 160 deg.
>
> Thoughts? I guess its time to take some temperature measurements.
>
> 73, Bob W9RAN
>
>
>



--
KPL


[Non-text portions of this message have been removed]

correction, single-throw is enough, newly-added thermostat can be just
switched paralel to the existing one.

On Fri, May 10, 2013 at 2:04 PM, KPL <kpl.listes@...> wrote:

> I did a bit differently - did not replace existing thermostat, but added
> another one, with a switch to choose between them. That way, laminator can
> be used for original purposes too.
> Even better way should be to add also the lower-temperature one, so the
> half-power heating starts a bit later, otherwise it takes a very long time
> to heat to 160C. But I did not have a small double-pole double-throw switch
> handy at the moment...
>
>
> On Mon, May 6, 2013 at 7:17 AM, w9ran <w9ran@...> wrote:
>
>> **
>>
>>
>>
>>
>> > Have you traced out the schematic and can post for us?
>>
>> I have uploaded a copy of the wiring diagram into the Files Section under
>> "Laminator Mods".
>>
>> I'd appreciate comments from anyone who is interested in modifying this
>> cheap (<$25) laminator that uses bimetal thermostat switches for temp
>> control. Ultrakeet in OZ replaces the thermal protector (fuse) with a new
>> 250 deg. one, and swaps a new 160 deg. thermostat for one of the existing
>> ones. My question to the group was "which one" to replace, as the CS-923
>> has three of them instead of two as in the Ultrakeet example.
>>
>> Here's how the laminator control system works: The heater elements
>> (connected in series with the thermal fuse) are powered from either
>> half-wave or full-wave rectified AC line voltage, depending on temperature.
>> At power-up, both thermal switches are closed, which provides full-wave
>> rectified voltage to appear across the heater element. Once the temp rises
>> to either 115 or 125 deg and the low voltage thermostat opens, one
>> rectifier will be disconnected and the heater will only see negative
>> half-cycles, reducing the average voltage by about one-half. When the heat
>> rises to the point where the 145 deg. thermostat finally opens, all power
>> will be removed and the heater will begin to cool and the green LED will be
>> off until the stat re-closes.
>>
>> Thus in normal operation the temperature is controlled in the range of
>> the selected lower-temperature stat and 145 deg. The behavior of this
>> control loop is going to depend a lot on the thermal response of the
>> heater-roller mass. If the temp were to drop below the threshold of the
>> low-temp switch, it will close and again supply the higher average voltage
>> to the heater to bring it quickly up to temp, but otherwise it seems that
>> the 145 deg. thermostat will do most of the controlling. It's a pretty
>> clever design, based on a few inexpensive parts.
>>
>> So the answer seems to be to substitute the new 160 deg. stat for the 145
>> degree one, which will allow the laminator to reach a higher temperature
>> before it shuts off. However, one could also replace one of the low-temp
>> stats and thus reverse the function, so that the full voltage would be
>> applied until the 145 stat opens, which would presumably maintain the
>> temperature between 145 and 160 deg.
>>
>> Thoughts? I guess its time to take some temperature measurements.
>>
>> 73, Bob W9RAN
>>
>>
>>
>
>
>
> --
> KPL
>



--
KPL


[Non-text portions of this message have been removed]