How To Make A Heating Coil

How to make a Heating Coil Chemical element Jig

Simple Build Jig for making Resistance Ringlet Heating Elements

Whilst I was making an electric foundry, I realised I needed resistance heating coil elements - those spring similar things you lot see in one-time electrical fires. Now these are cheap enough on the internet but I believe you go what you pay for and I wanted to use superior Kanthal wire. As such I came upward with a very unproblematic jig that anyone can brand from a couple of scraps of wood.

Practice The Jig

To be honest it's more complicated to explain than information technology is to testify, and so this is one of those occasions when I'd strongly recommend watching the accompanying video as this will explicate its uncomplicated structure and employ in just a couple of minutes.

How Do Resistance Coils Piece of work?

So what is a resistance coil and how does it work? Well the clues are in the proper noun.

Curl : A coil is a length of wire wrapped in tight circles. The purpose of the coil is to reduce the apparent length of the wire. The resistance wire involved in a curl may be surprisingly long but by coiling it, it'south possible to dramatically shorten the eventual length. For example, I made a ringlet containing 7 meters (23 anxiety) of wire, but the coil itself was quite short, maybe 15cm (6 inches) or so. That'due south quite a space saving and this allows the furnishings of the wire to be full-bodied in a smaller expanse.

RESISTANCE : The length and thickness of the wire decide how much electrical resistance the wire carries. Mostly, the thinner or longer the wire is, the higher the resistance. Similarly the shorter and thicker the wire is, the lower the resistance. Equally electrical resistance occurs within a wire, heat is generated. If the wire is capable of handling estrus for prolonged periods and the conditions are just right, it's possible to make the wire glow red hot - and that'southward what a resistance heating coil element is.

Ability : The strength of a heating curlicue is determined by its resistance, electric current and voltage. This strength is termed 'ability' and this is measured in Watts (or Kilowatts for e'er thousand Watts, and then 1000W is 1KW).

The pull a fast one on is to work out how long a length of wire is needed to determine these platonic conditions and this comes downward to maths.

Maths Involved...

Whilst the jig is very easy to brand and use, at that place are some maths considerations that demand to be looked at. Simply to brainstorm, we need some information...

Voltage : This is the mains voltage in your area or the voltage you know you lot are going to utilise to your coils. For instance, I live in the U.k. and hither the mains voltage is 230 volts, though it tin fluctuate very slightly between areas and suppliers. It'southward therefore useful to take a reading if you require accurateness.

Current Max : This is the maximum electric current you feel your outlet (and heating coil) can safely handle. In the U.k., the boilerplate outlet is rated at a maximum of xiii Amps and that's a lot of electric current. Personally I wouldn't desire to take my power consumption right to the limit, and then I punch downwards a little and opt to for a maximum usage of 10 Amps.

Resistance Per Meter : The wire you source to make your coil should be defended resistance wire intended for use in coil element manufacture. Every bit such it should be rated past the manufacturer and state the resistance the wire offers, commonly in Ohms per meter. For example, I purchased some Kanthal wire which had a diameter of ane.02mm (18 AWG) and a resistance of 1.73 Ohms per meter.

Inner Diameter of Curl : The terminal consideration when making a roll is the size of each circumvolve of the coil. This is of import data equally it helps decide how long the curl needs to be. Plain bigger coils will utilise more wire and thus reduce overall coil length - and vice versa of course.

Calculations

To make lifge easier, I've provided a Coil Making Computer that will do much of the folowing maths for you. But for those interesting in number crunching, let's starting time with Power.

POWER

Physics gives us the formula P = IV (ability = current x volts). So permit's say the Voltage is 230 and the current is 10 Amps. This would give us a potential power rating of (230 x 10) 2300 Watts (two.iii KW).

Physics besides gives u.s. another useful Power formula which is P = I² R (Power = Current Squared x Resistance). And so let'south say our current is still 10 Amps and our resistance is 23 Ohms. This would give us a potential power rating of (ten² ten 23) 2300 Watts (2.3 KW).

VOLTAGE

If we don't know the voltage, we tin can turn to Ohms Law formula V = IR (Voltage = Electric current ten Resistance). So with current of x Amps and resistance of 23 Ohms we could establish, in this example, a voltage of (10 ten 23) 230 Volts.

RESISTANCE

If the resistance of a excursion is unknown, we tin can again turn to Ohms Law and rearrage the formula to give us R = V / I (Current = Volts / Resistance). So as an example, Volts of 230 divided by a Electric current of 10 Amps gives the states (230 / ten) 23 Ohms.

Where could also rearrange the Power formula to calculate resistance, ie R = P / I² (Resistance = Power / Electric current Squared). So as an example, Power is 2300 Watts divided by a Current of 10 Amps squared gives us (2300 / 10²) 23 Ohms.

CURRENT

Merely as with resistance, we can use Ohms Law and rearrage the formula to give usa current with I = V / R (Current = Volts / Resistance). So equally an example, Volts of 230 divided by a resistance of 23 Ohms gives usa (230 / 23) 10 Amps.

Rearrange the Power formula to calculate current with I² = P / R (Electric current Squared = Power / Resistance). So as an case, Power is 2300 Watts divided by a resistance of 23 Ohms gives us (2300 / 23) 100 Amps - and when nosotros get the square root of this it gives united states of america 10 Amps.

WIRE LENGTH

The last thing we need to consider is the length of the wire. If you're making a coil, you'll demand to summate the resistance needed and from that it's a unproblematic matter of calulating the length. Fifty = R / r (which is a terrible made up formula significant Length = Resistance / Resistance per unit length). For example, nosotros know our resistance is 23 Ohms and I mentioned earlier the given resistance per meter on my wire is 1.73 Ohms (23 / 1.73) which gives the states a length of wire of 13.ii metres required.

Online Estimator

To make lifge easier, I've provided a Coil Making Calculator that will do much of this maths for you. To use it, click hither.

Stretching The Coil

Ane last matter - before using the coil it must exist stretched. If you neglect to stretch it you've basically got a solid length of metallic with no resistance.

Stretching is piece of cake enough. Simple securely grab each end and pull. You may need to do this a few times. It'due south generally considered a bad thought to stretch the coil longer than three times its original (unstretched) length.

Source: https://www.vegoilguy.co.uk/coil-making-jig.php

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