Help finding resistor

[elvislives]

Hi, i have a 240v 120w set of Liveryman horse clippers that have broken. One of the two motor brushes snapped off causing the resistor that connecs it to snap. I have got new brushes but now need a new resistor. Looking at the colour coding it is Gray, Red, Gold and Silver which i think is an 8.2 ohms 10% resistor. However, as it is 240v 120w, i am not sure what to buy.

Can anyone send me a link to a resistor in the UK? I presume that a 1/4w resistor wont be man enough, but i dont know that much about electronics.

The picture shows the resistor next to a ruler for sizing.

[David]

8.2 ohms 10% is correct. If the whole current is passing through the resistor, it will be dissipating something like 2watts. As long as the resistor is rated for more than this, the actual rating is not really significant. A good option would be to get (say) a 5w resistor if it will go in the space available.

Resistors are ubiquitous, and if you have a local Maplins they will have a good stock. Otherwise Google will be an obvious starting point. Take care when you are working with mains appliances.

[elvislives]

Thanks for the reply David.

I have searched around, and all I can find are 1/2 watt 8.2 Ohm 10% resistors. I had a look on Maplins website and couldn't find anything rated as 2 or 5 watt.

Am I missing something here? Would you be able topoint me in the right direction, because Google isn't being my friend on this one.

[David]

Maplins certainly seems to have a poorer selection of resistors than I expected. However they do have a 10 ohm 10 watt wirewound resistor. As the actual resistance of low value resistors in small motor circuits is not usually very critical, I suggest you get one of these and try.

Let us know how you get on!

[elvislives]

Thanks again David.

So if the actual resistance isn't too much of an issue, will a 10 ohm 2 Watt 2W 1% Metal Oxide Film Resistor be okay? I found this one on Amazon http://www.amazon.co.uk/Watt-Metal-Oxid ... stor+10%25.

[David]

Try one. Should be OK. Even if it burns up it won't have cost much.

[elvislives]

Hi David, I found an 8.2 ohm 2w resistor online and so bought 5. However, they are massive in comparison to the one it is replacing. Based on the image below, would you say that it should be a 1/4w, or 1/2w one, or is the size not important? The one that I bought will be to big to fit into the clippers.

image.jpg (137.15 KiB) Viewed 6909 times

[David]

I was not aware that space is so very tight around your motor, so your only option would seem to be to get some smaller resistors and try them. It could be that the motor is arranged such that the whole of the current does not go through these resistors. Try to find a 1W size, and ask for the dimensions before you buy.