How to mod a heat gun to blow cold?

My 1500 Watt heat gun has 2 settings, 630* F and 1000* F.

The fan motor is a 17 VDC motor and there is a 4 diode bridge rectifier
mounted on it.

On Low the AC plug measures ~ 15 Ohms

On High it measures ~10 Ohms.


I would like it to run on High when heat is needed, and when I switch
to Low, I would like the fan speed to remain high but with no heat (for
cooling).

How can I determine the fan motor current in order to calculate the
appropriate dropping resistor?


Am I missing something here?


Is there an easy way to do it?

 

[Homer J Simpson]

<stu@aaronj.com> wrote in message
news:1163865998.533318.86490@j44g2000cwa.googlegroups.com...

I would like it to run on High when heat is needed, and when I switch
to Low, I would like the fan speed to remain high but with no heat (for
cooling).

IIRC some of these use the heat element to drop the motor voltage via a tap
so you are SOL on this.

 

Homer J Simpson wrote:

stu@aaronj.com> wrote in message
news:1163865998.533318.86490@j44g2000cwa.googlegroups.com...

I would like it to run on High when heat is needed, and when I switch
to Low, I would like the fan speed to remain high but with no heat (for
cooling).

IIRC some of these use the heat element to drop the motor voltage via a tap
so you are SOL on this.

Yes, I understand whatg you are saying.

However, I have a hair dryer with a cold setting.

It should be the same principle.

 

Homer J Simpson wrote:

stu@aaronj.com> wrote in message
news:1163865998.533318.86490@j44g2000cwa.googlegroups.com...

I would like it to run on High when heat is needed, and when I switch
to Low, I would like the fan speed to remain high but with no heat (for
cooling).

IIRC some of these use the heat element to drop the motor voltage via a tap
so you are SOL on this.

Yes, I understand what you are saying.

However, I have a hair dryer and it has a cool setting.

It should be the same principle asmy heat gun.

 

[Michael Black]

(stu@aaronj.com) writes:

Homer J Simpson wrote:
stu@aaronj.com> wrote in message
news:1163865998.533318.86490@j44g2000cwa.googlegroups.com...

I would like it to run on High when heat is needed, and when I switch
to Low, I would like the fan speed to remain high but with no heat (for
cooling).

IIRC some of these use the heat element to drop the motor voltage via a tap
so you are SOL on this.


Yes, I understand what you are saying.

However, I have a hair dryer and it has a cool setting.

It should be the same principle asmy heat gun.

Why?

A hair dryer wants the cool setting, so they design it that way.

There is no conceivable reason why a heat gun would need a no-heat
setting. It's purpose is to generate heat, and nothing else.

If you want a fan with no heat, then use the hair dryer.

I would also suggest that no heat is not the same thing as cooling.
Turning off the heat element in a heat gun is just a fan, sort of
some cooling effect but nothing dramatic.

The opposite of a heat gun would be a bun with a fan and some sort
of cooling element.

Michael

 

Why?

A hair dryer wants the cool setting, so they design it that way.

There is no conceivable reason why a heat gun would need a no-heat
setting. It's purpose is to generate heat, and nothing else.

If you want a fan with no heat, then use the hair dryer.

I would also suggest that no heat is not the same thing as cooling.
Turning off the heat element in a heat gun is just a fan, sort of
some cooling effect but nothing dramatic.

The opposite of a heat gun would be a bun with a fan and some sort
of cooling element.

Michael

A conceiveble way; use the heat gun to roast coffee.

(Google heat gun roasting.)

The 'cool' setting allows one to cool the beans.


Cooling means to lower the temperature from where it is, not
necessarily below RT.

A helpful suggestion would be preferable to criticizing the question.

 

[Homer J Simpson]

<stu@aaronj.com> wrote in message
news:1163871656.976209.256590@h54g2000cwb.googlegroups.com...

A helpful suggestion would be preferable to criticizing the question.

Many times the most helpful suggestion is to criticize the question. However
try a 4.7K resistor and measure the voltage on the motor. That'll be a clue
to the best value.

 

Homer J Simpson wrote:

stu@aaronj.com> wrote in message
news:1163871656.976209.256590@h54g2000cwb.googlegroups.com...

A helpful suggestion would be preferable to criticizing the question.

Many times the most helpful suggestion is to criticize the question. However
try a 4.7K resistor and measure the voltage on the motor. That'll be a clue
to the best value.

That's a prett5y good idea.

Thanks.

BTW can you please explain how the heating coils control the
voltage/current to the motor?


I assume (perhaps incorrectly) that the 13 Amps going through the coil
do not also go through the motor.

 

[Homer J Simpson]

<stu@aaronj.com> wrote in message
news:1163873251.852366.107500@h48g2000cwc.googlegroups.com...

BTW can you please explain how the heating coils control the
voltage/current to the motor?

Yep

I assume (perhaps incorrectly) that the 13 Amps going through the coil
do not also go through the motor.

Yep. The heating coil drops 120 VAC over its length. There is a tap at, say,
15 VAC. This feeds the rectifiers and the motor. Older models used a 120 VAC
motor but this is cheaper.

 

[ian field]

<stu@aaronj.com> wrote in message
news:1163873251.852366.107500@h48g2000cwc.googlegroups.com...

Homer J Simpson wrote:
stu@aaronj.com> wrote in message
news:1163871656.976209.256590@h54g2000cwb.googlegroups.com...

A helpful suggestion would be preferable to criticizing the question.

Many times the most helpful suggestion is to criticize the question.
However
try a 4.7K resistor and measure the voltage on the motor. That'll be a
clue
to the best value.


That's a prett5y good idea.

Thanks.

BTW can you please explain how the heating coils control the
voltage/current to the motor?


I assume (perhaps incorrectly) that the 13 Amps going through the coil
do not also go through the motor.

Just like the dropper resistors in the heater chain of an old AC/DC tube
radio.

 

[Radiosrfun]

"ian field" <dai.ode@ntlworld.com> wrote in message
news:4OI7h.43964$163.22274@newsfe6-gui.ntli.net...

stu@aaronj.com> wrote in message
news:1163873251.852366.107500@h48g2000cwc.googlegroups.com...

Homer J Simpson wrote:
stu@aaronj.com> wrote in message
news:1163871656.976209.256590@h54g2000cwb.googlegroups.com...

A helpful suggestion would be preferable to criticizing the question.

Many times the most helpful suggestion is to criticize the question.
However
try a 4.7K resistor and measure the voltage on the motor. That'll be a
clue
to the best value.


That's a prett5y good idea.

Thanks.

BTW can you please explain how the heating coils control the
voltage/current to the motor?


I assume (perhaps incorrectly) that the 13 Amps going through the coil
do not also go through the motor.


Just like the dropper resistors in the heater chain of an old AC/DC tube
radio.

I have to check my heat gun - it's been a while since I've used it - due to
too many other projects not requiring it. Anyway, I "believe" MY heat gun
"did" come with a "cool" setting. I'll let you know. IF IT DID, I'll give
you the make of it. But in the mean time, I "think" I bought it from MCM
electronics, if I'm not mistaken.
Though they may not sell "that" model anymore.

 

[James Sweet]

I have to check my heat gun - it's been a while since I've used it - due to
too many other projects not requiring it. Anyway, I "believe" MY heat gun
"did" come with a "cool" setting. I'll let you know. IF IT DID, I'll give
you the make of it. But in the mean time, I "think" I bought it from MCM
electronics, if I'm not mistaken.
Though they may not sell "that" model anymore.

Mine has a cool setting which I've only ever used to cool down the heat
gun before putting it away, still I've managed to melt some stuff to the
metal barrel. It uses an AC fan motor.

 

Homer J Simpson wrote:

stu@aaronj.com> wrote in message
news:1163873251.852366.107500@h48g2000cwc.googlegroups.com...

BTW can you please explain how the heating coils control the
voltage/current to the motor?


Yep

I assume (perhaps incorrectly) that the 13 Amps going through the coil
do not also go through the motor.

Yep. The heating coil drops 120 VAC over its length. There is a tap at, say,
15 VAC. This feeds the rectifiers and the motor. Older models used a 120 VAC
motor but this is cheaper.

O.K. I understand the tap at ~15 Volts. The low current (~ 100 Ma)
does not load the parallel tap. However, how do you run the fan motor
with the coil not supplying heat?


I do not see a resistor in my 1600 Watt hair dryer which has a push
button cool switch.

AAMOF The cool postion of the hair dryer is a little warmer body temp
(some coil heat).

One way to achieve a cooler air stream is to series connect the 2
coils.

Higher resitance coil - low Heat.
Higher ressistance and lower resistance coils in parallel for max
heat.
(or just use lower resistance coil by itself)
Both coils in series for mostly fan.

 

[Homer J Simpson]

<stu@aaronj.com> wrote in message
news:1163890911.884132.279630@m73g2000cwd.googlegroups.com...

O.K. I understand the tap at ~15 Volts. The low current (~ 100 Ma)
does not load the parallel tap. However, how do you run the fan motor
with the coil not supplying heat?

I do not see a resistor in my 1600 Watt hair dryer which has a push
button cool switch.

Maybe you have an AC motor?

 

[James Sweet]

Homer J Simpson wrote:

stu@aaronj.com> wrote in message
news:1163890911.884132.279630@m73g2000cwd.googlegroups.com...


O.K. I understand the tap at ~15 Volts. The low current (~ 100 Ma)
does not load the parallel tap. However, how do you run the fan motor
with the coil not supplying heat?


I do not see a resistor in my 1600 Watt hair dryer which has a push
button cool switch.


Maybe you have an AC motor?

Or a 120VDC motor, I've seen them in paper shredders.

 

Homer J Simpson wrote:

stu@aaronj.com> wrote in message
news:1163890911.884132.279630@m73g2000cwd.googlegroups.com...

O.K. I understand the tap at ~15 Volts. The low current (~ 100 Ma)
does not load the parallel tap. However, how do you run the fan motor
with the coil not supplying heat?

I do not see a resistor in my 1600 Watt hair dryer which has a push
button cool switch.

Maybe you have an AC motor?

Nope. A 4 diode bridge.

 

[Dr. Anton T. Squeegee]

In article <1163865998.533318.86490@j44g2000cwa.googlegroups.com>,
stu@aaronj.com (known to some as stu@aaronj.com) scribed...

<snippety>

I would like it to run on High when heat is needed, and when I switch
to Low, I would like the fan speed to remain high but with no heat (for
cooling).

<snippety-two>

Point of interest: The Ungar 6966C heat gun has both 'Hot' and
'Cold' settings designed right in.

Happy heating.


--
Dr. Anton T. Squeegee, Director, Dutch Surrealist Plumbing Institute
(Known to some as Bruce Lane, KC7GR)
http://www.bluefeathertech.com -- kyrrin a/t bluefeathertech d-o=t calm
"Salvadore Dali's computer has surreal ports..."