Resistance Heating Wire-Designing a Round Wire Element

Tools

Resistance Heating Wire-Designing a Round Wire Element

Where:

V	Voltage (Volts)
W	Power (Watts)
S	Surface Area Loading (W/cm²)
R_t	Element Resistance at Operating Temperature (ohms)
R	Element Resistance at 20^oC (ohms)
F	Temperature-Resistance Factor
I	Wire Length (m)

Example:

1. To calculate the wire diameter and length required for a 750w/240v pencil bar fire element, operating at a maximum temperature of 1100^oC, the total resistance of the element at operating temperature (R_t) will be:

2. Using RW80 wire, the Temperature Resistance Factor (F) at 1100^oC is 1.071 thus the total resistance of the element at 20^oC (R) will be:

3. Knowing the dimensions of the pencil bar, the length of wire that may be wound round it may be estimated. Thus, the resistance required per meter of wire will be:

For example a length of wire of 9 meters -

4. RW80 of wire diameter 0.417mm has a resistance per meter of 7.91 ohms/m which is closest to 7.97 ohms/m.

5. To verify the actual wire length (L):

A change in wire length may mean adding or subtracting turns (altering the pitch of the wire) to achieve the total resistance value required.

6. To verify the surface area loading (S):

This surface area loading should fall within the range shown in the table for a pencil bar fire element noting that a higher value gives a hotter element. The surface area loading can be higher or lower if it is considered the heat transfer be better or worse, or depending upon the importance of the elements life.

If your calculated surface area loading is too high or low you should re-calculate changing one or more of the following:

- The wire length and diameter
- The grade of alloy

Pre Page: Resistance Heating Wire-Surface Area... Next Page: Resistance Heating Wire-Coiled or Spiral...

Product (745)

Product Forms (14)

Quality Certificate (11)

Learning Gallery (30)

Incoloy News (9)

Inconel News (22)

Molybdenum News (7)

Nikrothal News (4)

Nichrome News (13)

Titanium News (2)

Nickel News (8)

Alloys House (30)

Tools (27)

Nickel alloy News (30)

Latest Buzz (30)

nickel chrome copper iron alloys news (28)

Credit Report

Products Index

Company Info

Tools