8
The control section consists of a temperature controller, a
current controller, a transformer, a contactor (relay), a
circuit breaker, and a pilot light.
The temperature controller senses the furnace temperature
(by means of the thermocouple) and adjusts electricity to
the heating elements by means of the current controller.
The current controller controls electricity to the heating
elements by adjusting the magnitude of the electrical
current (rather than turning the electricity completely on or
off). This is the preferred method of controlling electricity to
molybdenum disilicide heating elements.
The transformer supplies the proper electrical voltage to the
heating elements.
The contactor removes electricity from the heating elements
if the furnace temperature equals or exceeds the high limit
set point of the controller
The circuit breaker is used to turn the furnace on and off
and also protects the electrical supply in the event that the
furnace draws too much electrical current.
The pilot light indicates that the circuit breaker is ON and
that the controller is being supplied with electricity.
A fan is provided in each section of the furnace to provide
forced air cooling.
Types of Controllers
1. The automatic (single set point) digital model enables the
user to program a single set point temperature which the
furnace will heat and hold.
2. The 4 program, programmable digital model enables the
operator to program up to 8 ramp segments (heat-up or
cool-down rate) and 8 dwell segments (soak) for applica-
tions that require time and temperature relationship for
up to 4 separate or linkable programs.
3. The 15 program, programmable digital model enables
the operator to program up to 8 ramp segments (heat-up
or cool-down rate) and 8 dwell segments (soak) for up to
15 separate or linkable programs.
D
ESCRIPTION
