About the main cause of slip rings catch fire

When they are made from wood, may be a possibility.

Sno-o-o-ort ;-)

...Jim Thompson

-- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | |

Win, I don't see you joke around much, but when you do, it's a zinger! ;-D

Cheers! Rich

According to your post in another thread, you're the slipring expert. So why don't you tell us your website address and then we'll know what sliprings not to buy.

slipring snipped-for-privacy@hotmail.com hath wroth:

Slip rings are made from copper alloy. Copper does not burn. The brushes are made from everything from conductive materials to powdered carbon and/or metalized graphite mixtures, which will burn quite nicely. If your brushes are on fire, you are probably drawing too much current, which is usually what happens when your rotor field windings develop a shorted turn or you overload your unspecified motorized contrivance. Slip rings are also used only in AC alternators, where a shorted diode can cause excessive current. You can also create a fire by using the wrong material for replacement brushes, the wrong size brushes, or insufficient contact area (high current density). If this happens to be an ST generator head you're trying to repair, the following might be useful:

Notice that on 5kw and up models, dual brushes are used on the slip rings.

The main cause would likely be: Extremely elevated temperature.