question about pilot light on an electric heater

Dec 07, 2005 6 Replies

Hello all,



I'm buying a home electric heater accumulator, but it doesn't have a pilot light, so I won't be able to know when it's charging



The heater accumulator solution is being promoted by the local utility supplier, in order to use more power at the night hours of the network



I would like to know when it's charging, so I'm thinking on joining, in serial, some sort of pilot light



Could somebody inform if there's a simple product that already does this? Other solutions?



The heaters' power is 1,7KW, on a 230V installation



Thank you, João


You may be able to install a switch w/ pilot light in the circuit. I seem to recall seeing pilot lit switches with an option of having the pilot light on current. Sorry if I'm sending you down the garden trail. If you are getting a switch make sure it is rated for whatever duty it's going to see.

j

A lamp in serial (assuming you mean series) will not do anything but prevent "charging" . The question is, how is it switched on to "charge" ? Is it some sort of time switch? If so, a small neon light (with appropriate resistance) or even a night light in parallel with the heater (and on the heater side of the switch) will do the job.

One posted solution was to use a small indicating light - a neon or a nite lit - in parallel with the heater. Here's another: use a CT (current transformer) with a burden resistor, a diode and an LED with a limiting resistor. This has the added benefit of telling you the heating element is working, not just receiving power.

TR-3025-S (Toroid Corp. of Md.) ========= Mains wire --------| CT |------------------ heater ========= | | [150R] | | | 1N4001 +-------+--[D1]--+ | | [47R] | | | +------[LED]-----+

One (and only 1) of the mains wires passes through the hollow center of the CT. When current is drawn by the heater element, a current is induced in the CT. The 150 ohm 1 watt burden resistor provides a path for the induced current, and an AC voltage of about 3.7 volts is created across that resistor. The 47 ohm 1/2 watt resistor limits the current to the LED to about 25 mA. The diode rectifies the AC to DC that the Red LED needs so that it is not exposed to reverse voltage.

Different CT's would require different calculations.

Ed

Thanks. That's seems to be a good simple solution

Thanks for the answer. There's in fact a time switch, activated at night hours. However, the resistances are active only until the refractory material reaches some high temperature (I think 650=BA Celsius). I wouldn't like to mess inside the heater, that's why I was thinking "series".

Thanks for the answer. The current transformer seems to be the more elaborate solution, but is very interesting. Maybe I'll pick it up if I can't find a simple swtich with a pilot light activated on current. In the end I can always feel the heat rising out of the chassis, or look at the power meter on the installation and figure out if the think is working or not. Thanks all for the answers.=20

Best regards, Jo=E3o

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