Hi

I’m thinking to build an Eddy current retarder capable of handling around 120kW perhaps a CC80 or CC100 would be a good choice. I’m undecided about the Chinese units and tried searching for a second hand unit here in Thailand but this is not so easy to find, the only one that pops up is a Telma Focal unit FN72-00 (F2000) that’s gearbox mounted and would require fabrication to provide a bearing support.

Are there any advantages / disadvantages to using a Telma retarder that’s too big for the job ?

If I do roll with the DIY version one feature I’d like to implement is a water cooled disc.

The one area I have no idea about is the coil specs, I guess I could buy Coils or a DIY option to wind your own. If anyone has any experience and knowledge with rewinding a coil I’d appreciate your input to my questions below?

1. What was the wire diameter used
2. How many meters of wire per coil.
3. Coil Resistance
4. Dimensions of the coil ID x OD x Height

I found this on the tractor Sport forum…maybe it’s a good starting point. http://www.tractorsport.com/forum/viewtopic.php?f=22&t=1297

The central iron magnetic core was 80mm in diameter and 90mm long (face to face). The coil consisted of 380 turns of 2.0mm diameter copper wire. Outside diameter of this coil 125mm. This is a twelve volt coil, the electrical resistance ends up being around 0.695 ohms, and it draws 17 amps at 12 volts. This is for a fairly large retarder. Sixteen of these coils will hold 900 Ft/Lb of torque at 4,000 rpm (685 Hp)

Thomas