Heater controller?

[mr.z]

Howdy all..

This maybe a weird one or one you've seen before..

http://www.astro.uwo.ca/~rasc/HEATER.pdf

This is the controller i was thinking of useing.. would this be suitable for whats needed below? + it will be closer to 14v not 12, presumeing that makes a significant differeance

supposedly...

Up to 10-12 W per hand, so 12-14 Ohms per length of wire
For a continuous 5 ft length, we'd need 2.4-2.9 ohm/ft.

Ive got some Nichrome resistance wire, 0.9mm tickness, how would this compare? how much would i need to get 11watts worth of heat (or there abouts, more is ok provided i can reduce it with the above)


Eventually these would be going in some motorcycle gloves, or heated muff type things, depending.. so i dont want them seting on fire as you can imagine! i was even considering an overglove the attaches to the back of the gloves insulateing and adding heat where its needed..

Anything i should know? :P (its only getting colder here!)

[ante]

Hello mr.z,

It’s OK to use up to 14 volts. What decide the maximum voltage for the circuit is the 555 and the electrolytic capacitor (16V).
When it comes to bikes, usually the heaters are built into the handles not in a pair of gloves. The NiCr wire will probably break off due to movement fatigue in a glove.

I hope this helps.

[mr.z]

Thanks for the reply very much appreciated!

Yeh i think your right about the constant movemnt stress (specially since is such a small diameter) the slightly revised plan is to use the wire in a overall hand covereing (commonly known as muffs! )

Is there anywhere in the uk where suitable complete pwm units can be gotten? i'm struggleing to find the parts! (namely the mosfet part)

Thanks again..

[ante]

I don’t believe you can buy this circuit ready built , perhaps something similar or you could use a simple light or DC-motor PWM controller. . The Mosfet used in this circuit can be replaced with many other n-channel types, ask you local parts dealer for a similar one. A few equivalent types are mentioned in the part list, there are many more.