Electric Heater works under high temperature. Normally an Electric Heater would fail, when its heating wire melt down. So to get your heater deliver its intended job done for an appreciated long time, some precautions should be taken. The very important thing to be taken into consideration is the heater sheath watt density. A sheath watt density can be defined as the total rated power divided by its exposed surface area from which heat is to dissipated. It Should be noted that for a given size Heater (for instance a
Tubular Electric Heating Element), the watt density depends upon the medium to be heated and its surrounding environment. For Example a heater designed to heat water can not be used in open air, if, when used, will burn sooner it reach its failure temperature. Other Precaution Required to be taken is to check with the connection. Since an electric heater works in a high temperature environment, the heater terminal are usually equipped with post terminals (screws and nuts). If the connection wire is not tightened properly or loosely held, it would then result in arching at the terminal. This arching have two effects:
1. Because of arching the voltage surge can be around thousands volts which is enough to create a breakdown for heater insulating material.
2. Terminal will Burn Resulting in an open ended circuit.
The Above discussion is valid to a single phase and a three phase connected heater. But for a three phase connected heater, especially for a star connected heater, it have been seen that if the heater connected are not balanced, then it can, again be a cause of heater failure. For that reasons it is suggested by heater manufacturer not to mix old heater with a new one.
Conclusion: It is to be noted that, for an electric heater, proper watt density should be selected rather than total wattage depending upon the operating environment. Also check with the proper connection and the fashion (star or delta) in which these heater are to be used with. By ensuring these little things you can expect a long heater life and with desired results.
