Auber WS-1500ES Betriebs- und Gebrauchsanleitung - Seite 17

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Appendix 1

Managing the heat generated by the controller

The heat dissipation of the controller is directly related to the electric current drawing

power of the heater. If your cooker consumes less than 10 ampere of current or your pot

is less than 5 gal (19 liters), you do not need to worry about the heat generated by the

controller.

Sometime, the AC current requirement might not be marked on the cooking appliance.

To find out how much current it will draw, divide the power (in wattage) by the line voltage,

for example, an 1800 watts 120V heater will draw 15A. A 2000 watts 240V heater will

draw 8.3 Ampere.

Why the heat becomes an issue?

The solid state relay (SSR) used in the controller is a critical component for the precision

temperature control. With SSR, the power can be switched at high speed with no noise

and no life time limitation. Compared with electromechanical relay, however, SSR has

one drawback. It generates heat when passing the current. SSR is made of

semiconductor that has a limited conductance. When passing current, the heat will be

produced from the resistance. Each ampere of current will produce about 1.3 watts of

heat. When 12 Amp is passing through the controller, 16 watt of heat is produced in the

controller. As more heat is produced, the temperature inside the controller will rise. If it

reaches to higher than 70 °C, it can shorten the life or even damage some the

components in the controller. The temperature inside of the controller depends on the

amplitude of the current, how long the controller needs to run at full power and the

ambient temperature.

The heat is only an issue during the start of the heating when the heater is running at full

power. Once the temperature is close to the set point, the controller will probably need

less than 50% of the power to maintain the temperature. Since the heat is directly related

to the current passing the controller, the heat produced at steady state will be

insignificant and can be ignored.

When the heat becomes an issue?

This controller can run at 10 A continuously without worry of the temperature of the

controller. At 12A, the temperature of the controller will increase with time. The bottom of

the controller where the heat sink is located can rise by 63 °F (35 °C) from ambient if

running at full power continuously for 90 minutes. For this reason we don't recommend

running the controller at full power for more than 90 minutes. For 120 VAC, 15 A for 90