2 replies to this topic

[chyke7]

 This sounds simple but i need some clarifications. I am using a hot plate to heat a solution  in an oil bath. The power rating and maximum temperature of the hot plate is 1520 W and 500 oC respectively. I set the hot plate temperature to 140 oC based on my experiment. How can i determine the exact/near exact power output (W) of the hot plate at 140 oC?

 

I attached the sample set-up.

 

Many thanks for your expected assistance.

Attached Thumbnails

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[MrShorty]

1st thought. Do you know what kind of control algorithm your hot plate uses? Those around our lab seem to use a "pulse width" type algorithm, where the hot plate controls the time that the heater is on. If you have a 1.5kW heater and it is on 1/3 of the time, then the average output of the heater is 0.5 kW. The challenge here would be to measure the "on time" and "off time" of the heater.

 

If the heater is being controlled by varying the voltage/current through the heater, then you would "simply" need to measure the voltage and/or current and/or resistance of the circuit and determine the power from Ohm's law and Joule's law.

 

Those seem to me to be the most direct ways to measure the heater output.

[curious_cat]

When we had a Linux Server whose Power draw we wanted to measure we used a small plug in type Wattmeter. That sounds about in the right range for your application. That server was rated around 2 kW. 

 

Essentially it plugs in into your socket and you keep it plugged for a certain time and it will tell you the kWhrs drawn through the socket in that much time. Not sure how accurate that is though.