I have a 13 month old Beko WM6167 that is now on it’s third set of brushes. Each time on replacing the brushes, one brush is completely worn and the other is about 15mm to 20mm in length. After fitting the latest set, I ran the machine on a spin cycle and watched the motor as it gained speed. On the lowest and itermediate speeds everything appears fine but, as soon as the motor switches to the highest speed, the brushes start arcing and crackling. Can anyone suggest what the cause is likely to be?