Catalogue Plastics catalog
www.watlow.com
print switch display
Page / 411
Where to buy
this product ?
Request
a Quote
Watlow - 5551, 81623
/ 411
See other catalogues for Watlow
Text version of the page
2.To use the formula below, insert the no heat factors, diameter and width (in inches).
Heated Area =
(3.14 x Diameter - No-Heat
Factor) x Width
MI Band
Applications and Technical Data
Calculating Watt Density
Watt density is the amount of wattage per square inch of heated area. To determine watt density, divide the total wattage by the heated area.
Heated area is the total contact surface of the heater less areas of no heat that are found around terminals, mounting holes, etc.
Heated Area =
Total Contact Area - No-Heat Area
To calculate the heated area:
1. Locate the no-heat factor from the chart below that corresponds to the type of heater being considered.
Total Watts Heated Area
Watt Density =
Type
Factor
(in.)
1 pc. lead unit Type B, C,
H, E or 90°B
(1.37)
1 pc. post terminal
(1.60)
2 pc. expandable post term
(3.18)
2 pc. expandable lead unit
(3.00)
To apply this equation we must define the term "heated area."
Maximum Allowable Watt Density
The following derating factors apply to the Maximum Allowable Watt Density chart, which are shown in both metric and inch base for convenience. Please review these factors and the chart to determine the correct watt density curve for your application.
Derating Factors:
• For units over 51 mm (2 in.) in width, multiply wattdensity by 0.8.
• In applications where unusual operating conditions are present, such as irregular mounting surfaces, contact the Watlow factory in St. Louis, Missouri,
for watt density limitations.
• For two-piece units used in vertical applications, refer to Clamping Matrix Application Guide, page 21.
• For applications where insulating blankets are used, multiply W/cm2 (W/in2) by 0.75.
20
DirectIndustry's Virtual Technical Library: PDF Catalogue | Technical Documentation | Brochure | Manual | Industrial directory | Specifications | Characteristics
Search Go
Contents table 1 - 2
page 1 p.1
page 2 p.2
page 3 p.3
page 4 p.4
page 5 p.5
page 6 p.6
page 7 p.7
page 8 p.8
page 9 p.9
page 10 p.10
page 11 p.11
page 12 p.12
page 13 p.13
page 14 p.14
page 15 p.15
page 16 p.16
page 17 p.17
page 18 p.18
page 19 p.19
page 20 p.20
page 21 p.21
page 22 p.22
page 23 p.23
page 24 p.24
page 25 p.25
page 26 p.26
page 27 p.27
page 28 p.28
page 29 p.29
page 30 p.30
page 31 p.31
page 32 p.32
page 33 p.33
page 34 p.34
page 35 p.35
page 36 p.36
page 37 p.37
page 38 p.38
page 39 p.39
page 40 p.40
page 41 p.41
page 42 p.42
page 43 p.43
page 44 p.44
page 45 p.45
page 46 p.46
page 47 p.47
page 48 p.48
page 49 p.49
page 50 p.50
Pages:
1-50
51-100
101-150
151-200
201-250
251-300
301-350
351-400
401-411
pdf-page pdf di En 2008-11-47-22