Datasheet

21
Introduction
Design
Guide
Polyimide
Heaters
Silicone
Rubber
Heaters (foil)
Standard
Polyimide
& Rubber
Rubber
Heaters
(wire-wound)
Mica Heaters
Thermal-Clear
Heaters
All-Polyimide
Heaters
Sensors,
Controllers &
Accessories
Reference
|
Flexible Heaters Design Guide | www.minco.com
Specifications subject to change
Mica Thermofoil™ Heaters
Specifications
Temperature range: -150 to 600°C (-238 to 1112°F).
Lead tab area: 538°C (1000°F) max.
Resistance tolerance: ±10% or ±0.5 Ω, whichever is greater.
Dielectric strength:
0.010" (0.3mm) insulation: 1000 VRMS.
0.020" (0.5mm) insulation: 2000 VRMS (recommended for
over 250 V).
Mounting: Must be clamped to heat sink using bolt holes
provided in heater and backing plate. See the mounting
diagram below. Please refer to Minco Engineering
Instruction #347 for detailed installation information.
Burn-in: Organic binders will burn off, producing small
amounts of smoke, when heaters are first powered. After this,
layers can separate so heaters should not be reinstalled.
Leadwire: Mica/glass insulated, stranded nickel-clad copper,
potted over termination with high temperature cement.
Maximum heater thickness:
Mica insulation Over heater element Over lead termination
0.010" (0.3 mm) 0.030" (0.8 mm) 0.200" (5.1 mm)
0.020" (0.5 mm) 0.050" (1.3 mm) 0.220" (5.6 mm)
Current capacity (based on 100°C max. ambient temp.):
AWG 22 - 8.0 A
AWG 20 - 9.0 A
AWG 18 - 11.0 A
Installation instructions
Minco Engineering
I
nstruction #347
describes mica heater
installation in detail.
Contact Minco for a
copy or download
the document at
www.minco.com
Backing plates
Backing plates are 0.0625" (1.6 mm) thick stainless steel with
pre-drilled holes matching the bolt pattern of the specified
model. These backing plates do not have cut out areas for the
lead bulge and may require modification.
How to order backing plates
Order part number AC6800 for HM6800, etc.
Ceramic paper and mica sheets
Each mica heater is supplied with two pre-trimmed sheets of
0.125" (3.2 mm) thick ceramic fabric paper for use as a resilient
pad between the heater and backing plate. This paper does not
have a cut out area for the lead bulge. If the backing plate
being used does not have a cut out area for the leads attach-
ment you must use two pieces of this paper and make this cut
out in each. Contact Minco to order additional ceramic paper.
Mica sheets
Additional layers of 0.010" (0.3 mm) mica trimmed to the
heater size are also available. Using an additional layer of mica
will increase the dielectric strength, but it will also reduce the
watt density limit by up to 50% across the temperature range.
If used on the lead bulge side of the heater then the mica must
be cut to allow for the ceramic and wires bulge on that side.
Contact Minco to order mica sheets.
0
10
20
30
40
50
60
70
80
90
100
110
120
-200°C -100°C 0°C 100°C 200°C 300°C 400°C 500°C 600°C
Maximum allowable power:
Watts/square inch of effective area
0.0
1.6
3.1
4.7
6.2
7.8
9.3
10.9
12.4
14.0
15.5
17.1
18.6
-328°F -148°F 32°F 212°F 392°F 572°F 752°F 932°F 1112°F
Watts/square cm
0.020“ (0.5mm) Mica
0.010” (0.3mm) Mica
MOUNTING METHOD:
Clamped
HEATER:
Example: At 300°C, the maximum power of a 0.010" mica heater is
70 W/in² (10.9 W/cm² ).
Rigid metal
backing plate
Ceramic paper
Mica
heater
Heated
piece
Mounting diagram
Mica Heaters
Maximum Watt Density