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I am working on a project with a mobile computer system which is installed in a vehicle. In the winter, the system can easily drop below the temperature specifications on the hard drive. I hope to find a solution that would warm the hard drive enough for it to start up, at which point the heater could be turned off, and the hard drive would then sustain it's own heat. Obviously thermostatically controlled, and 12vDC. After tirelessly searching the internet for heat strip solutions, I came across this site, which seems to have just what I need.

If anyone can offer a suggestion for my project, I would very much like to hear it. Contact information is also welcome. Feel free to email me at jesse_mccrostie@irco.com.

Thanks,

Minco has supplied a number of applications requiring the warming of the HDD in a portable computer. Most of these evolve to a custom design incorporating the control circuitry from the CT198 style sensorless controller to ensure the HDD is maintained above its minimum operating temperature. You should be able to accomplish roughly the same by selecting a heater strip that has one of the high TCR values and use it with a standard CT198 controller that operates from 12 vdc. Of course, you can also use a thermostat to turn the heater strip on or off, in which case it does not have to use the high TCR options.

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Vitreous Humor
"Eye can see clearly now..."

In a few of these HDD applications, the main concern has been heating the spindles from the top and bottom of the drive.  Use the online configurator to look for round Kapton heaters with the appropriate resistance and high TCR element (nickel or nickel-iron) for use with CT198 as Vitreous suggested.  Look at wiring them in series or parallel to get the correct resistance/power.  Also look at the power estimating engineering tool on this site which will help determine power requirements to achieve desired warmup time.  You can always get a custom heater designed for your application too.

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"A witty saying proves nothing."
-Voltaire

Thank you both for your assistance. I'm still a little lost, however. It seems like what I need isn't very complex, but with all the options available for each heater, I'm left a bit confused. You mention the Kapton heaters, but I wonder if they're a bit more than I really need. It seems as if the standard heaters with integrated sensors would work just fine. But there could certainly be something I'm missing or not thinking about.

A few more questions if you don't mind:

1) Why Kapton heaters instead of standard w/ integrated sensors?

2) What does a "high TCR element" mean? Is that the same as the sensor element?

3)What do the [CT198] controllers do? Is that in essence the equivalent of a thermostat?

4) How can I figure out what resistance I need? Heating up a 2.5" hard drive from just below freezing to above freezing shouldn't take very much I don't think.

I apologize for the mundane questions. I don't know much about this field or the technology involved. I suppose I wouldn't be here if I did though.

Thanks again,

-Jesse

1.  Kapton = polyimide.  The standard heaters with integrated sensors are Kapton Heaters.  I guess the reason for possibly choosing a  heater without a sensor (high TCR, to be explained) is the cost of the control system.   If you have a heater with a sensor integrated, you need a controller to read the input from the sensor and then regulate the heater.  This is one of the most precise and expensive ways to control your thermal system.

2.  It means that the heater element changes resistance with temperature, much like a sensor element does.

3. The CT198 reads the resistance of the heater and controls the heater to a setpoint, basically using the high TCR element as the sensor and the heater element.  The CT 198 is also usually less expensive than a traditional controller.

4.  Power = voltage^2 / resistance.  You need to first figure out how much power you need.  One of  the larger factor in this calculation is warmup time.  I have run a simple calculation for you with the following assumptions: 

Ambient Temp 0°F
Goal Temp 40°F

Warmup time (Watts Required):
1 minute (124 Watts)
3 minutes (41 Watts)
5 Minutes (25 Watts)

Resistance = voltage ^2 / Power

Now you know what resistance to look for!

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"A witty saying proves nothing."
-Voltaire