User Manual

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What are the size limitations for your SmartHeat
product line (i.e. the biggest and smallest heater
you can produce)?
The maximum size heating element that Minco is capable
of manufacturing is 7 in. x 22 in. Larger heaters can be
manufactured by combining (stitching) multiple heating
elements on a common polyimide substrate and cover.
The maximum size stitched heater Minco is capable of
manufacturing is 22 in. x 42 in.
The minimum size heating element that Minco is capable
of manufacturing is 0.5 in. x 1 in. Smaller heaters can be
manufactured by locating the termination area on an external
tab, or by using surface mount or pin-header connections.
Does SmartHeat take any longer to design or
build than a traditional etched-foil heater?
No, SmartHeat is built with the same methods and equipment as
a traditional etched-foil heater. Leadtimes between traditional
products and SmartHeat products are comparable. In cases
where the thermal load is significant or highly dynamic, multiple
prototype iterations may be required to achieve the designed
set point for the system. This is a normal part of the design
process that can be discussed up front with Minco Engineering.
What is the maximum power density that can be
achieved with SmartHeat?
SmartHeat strives to maintain a constant temperature and will
produce as much power as is necessary to maintain equilibrium.
Each heater will adjust its resistance, and in turn wattage based
on the heatsink, contact method, and environment temperature.
Minco designs heaters for a constant temperature. It is then up
to the surroundings to determine what the wattage and warm
up time will be when the heater is turned on.
The maximum power density is both application and design
specific. For new applications, it is recommended that customers
work with catalog/standard heaters for proof of concept testing.
This is the most reliable means to characterize SmartHeat’s
power density for a specific application.
What is the maximum current draw that should
be expected from SmartHeat during a cold start?
Is there any way to limit or reduce the startup
current?
Start current, similar to power density, is application and design
dependent. As a rough approximation, the start current can
range from 5x to 20x the steady state current. The exact value
is dependent on various parameters including the design
formulation, supply voltage, heater size, coverage, insulation,
and environment temperature on startup.
In cases where design strategies do not fully address startup-
current concerns, there are simple electrical components that
can be added to the heater design. Both fixed inductors and
negative temperature coefficient (NTC) thermistors can offer
a cost effective way to lower the startup-current while still not
adding the cost, weight, and complexity of an external control
system. The addition of the thermistor significantly reduces
the peak startup-current, but does slightly increase the time
required to get to steady state.
What is the difference between set point
temperature, element temperature, and safety
temperature?
Set point temperature is measured at the heatsink. It is the
desired temperature that the heatsink should be warmed to.
This value is generally customer driven and varies based on the
application and condition of the heatsink at equilibrium.
Element temperature is measured at the internal heating
element. This value is Minco driven and depends on the
connection method, environmental conditions, heatsink
type, and relative size of the heater to the heatsink. The
element temperature will always be higher than the set point
temperature due to thermal losses between the heating
element and the heatsink.
Safety temperature is the upper shutoff point for a SmartHeat
device. Above this temperature, the heater will produce
minimal power. This built in shutoff point is integrally tied to
the set point and element temperatures. SmartHeat devices
are designed to prevent thermal runaways and to protect
surrounding materials that are prone to thermal damage.
What temperature set points are available for
SmartHeat? Is the set point adjustable in the
field?
Minco is capable of designing SmartHeat for temperature set
point between 10°C and 70°C. Please consult your local sales
representative for applications outside of this range, or for
applications with high thermal loading (subzero climates or
dense metallic heatsinks).
Set point is established during manufacturing and cannot
be adjusted in the field, except through the use of a variable
voltage power supply.