wrote:
Mike Dodd wrote:
vairox wrote:

Hi, I'm working on a project and need a constant heat source (no open
flame) so an electric burner would be best, but from what I've read a
vast majority of them cycle on and off, is there a way to modify them
to make them run constant? like remove a resistor or something? this is
very similar to what I'm talking about

http://tinyurl.com/hoylu

any help would be awesome, thanks.

I'd expect any such source to use a thermostat to provide the "cycling"
- removing power from the element when the set temperature is reached,
then restoring power when the temperature drops below that temperature.
Often an embedded bi-metallic strip type device. If the device has a
variable temperature setting, this can be confirmed to a high degree of
confidence by adjusting the temperature setting with the device off, if
you get get the temperature setting down to room temp, and hear/feel the
contact open then you can be pretty sure it's a bi-metallic strip.

To bypass this type of device, simply short the terminals across the device.

Are you trying to hospitalise the OP?


Aha, I see you failed to quote my post that detailed the likely result
of what I suggested ("catches fire, melts, or goes bang"), despite
having clearly answered the OP's *specific* question as to how to modify
them to make them run constant.


Do not wire over the stat. Use a series impedance of some kind in
series with the heating element, keeping the fan on full mains voltage,
and set the stat to above the temp you want to get out. Use a
thermometer to measure what youre getting and adjust the impedance to
get the desired temp. This will give a stable temp once you've run it
for 5 minutes or so to stabiilse the temp of all the parts.

Suitable series impedances: _very_ big resistor, light bulbs,
capacitor(s), or suitably rated inductors. If tht heating elemnt is low
power (500w), a standard dimmer will work nicely.



Now that the OP has provided the proper statement of the problem, we can
progress. To be honest, at the temperature that he's citing I'd actually
recommend a variable-temperature immersion coil, into an oil bath, into
which the distillation vessel is submerged. That should provide a
reasonably controllable system, which, once up to temperature, the *slow
* addition of alcohol to the distillation vessel, and the relatively
slow rate at which the achohol boils off should not unbalance significantly.