User Manual

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Thermal Solutions Design Guide | Specifications subject to change
All-in-one Heater: A heater which incorporates the func-
tions of an external sensor and controllers.
Anti-reset windup: Turns o integral action outside the
proportional band to prevent false accumulation of error
during warmup.
AP (All-Polyimide): Flexible heaters with adhesiveless
substrate and covers. High temperature capabilities to
260°C.
AWG (American Wire Gauge): An indicator of wire
diameter. The larger the number, the smaller the diameter.
Carbon-Silicone Matrix (CSM): SmartHeat’s silicone layer,
embedded with carbon particles.
Conduction: The transfer of thermal energy between
adjacent bodies (usually solids) or parts of the same body.
Convection: The transfer of thermal energy in fluids
and gases by mixing warmer areas with cooler ones.
Convection currents can form, due to differences in
density. Generally, warmer fluids (or gases) are less dense
and tend to rise.
Coverage: Heater coverage is the percentage of the
available area within a heater that is covered with heater
element strands. Most of Minco’s heaters are designed
with 50% coverage but reduced or increased coverage can
offer advantages in some designs.
Creep action: A switching method, often used in
thermostats, in which a temperature-sensitive bi-metallic
element causes slow make and break of electrical
connections. In contrast to snap action, this method
results in tighter temperature control, but greater electrical
noise and usually shorter life.
Cycle time: The duration of an on/off cycle with time
proportioning. With cycle time of 10 seconds, for example,
80% power would give 8 seconds on, 2 seconds off.
General rule: Shorter times give better control and less
oscillation, but require solid state relay.
Damage-Tolerant: The characteristic of SmartHeat that
allows it to continue functioning after sustaining breaks in
one or more layers of the heater.
Deadband: The temperature difference between full
“on” (when temperature is falling), and full “off” (when
temperature is rising), for an on/off controller. The
deadband is intentionally designed to reduce oscillation.
Derivative: Adjustment to output based on the process’s
rate of change, usually to allow faster recovery from
upsets. Also expressed as “rate.” General rule: Increase
derivative time if system frequently overshoots; decrease if
system acts sluggish.
Dielectric strength: The maximum voltage (typically AC)
that an insulation material can withstand before material
break down occurs.
Droop: An error inherent in simple proportional control
where the temperature reaches equilibrium at a point
other than setpoint, but still within the proportional band.
Dual-element Heater: A Thermofoil Heater that contains
two heating elements within the same unit.
Etched-foil: A method of producing pre-determined
electrical paths, by chemically removing (etching) the
areas which will not carry electric current. This process
can be used to manufacture heaters, flex-circuits, and
temperature sensors.
FEA (Finite Element Analysis): A numerical method used
to predict the behavior of a heater/heat sink design. It is
typically employed only if actual modeling is not practical.
FEP (Fluorinated Ethylene Propylene): A thermoplastic
adhesive in the PTFE family of polymers.
Flex circuit: A printed circuit made with flexible materials
for compact electrical interconnects.
Heat sink: The body to which a heater is affixed.
Heat transfer: The transfer of thermal energy between
bodies of different temperature.
Heater Backing: A material applied to one or both sides of
a heater. A sheet adhesive, such as a PSA, can be used to
affix a heater to an object that must be heated. A foil layer
bonded to the surface can serve a variety of purposes. But
most often, it serves as a lateral heat spreader.
Heaterstat: A Minco temperature controller that uses the
heating element as a temperature feedback sensor.
Hysteresis: The temperature difference between full
“on” (when temperature is falling), and full “off” (when
temperature is rising), for an on/off controller.
Insulation resistance: The actual resistance of an
electrically insulating material. Measuring devices typically
use high DC voltage to perform the measurement.
Glossary
Minco’s heater terminology defined