Thread: METABO INDUSTRIAL DRILL & foto

When I first joined this forum I wasnt expecting to see such a fountain of well meaning knowledge, thoughts and ideas promulgated the way it is. And every so often a gem pops in (in this instance Gerhard particularly but all you other guys too ) and I'm blown out of the water. Previous attempts by me to obtain information from professionals on my drill problem has met with no reply at all and I guess it's like any intricate matter, you've got to know where to go.

So, before I order a part in i will reinspect my baby and look for any telltale signs of other symptoms but I am confident she hasnt had a hard life and cant wait to have her spinning again.

Thank you to all.

It may have been a while but it was worth the wait. From the info supplied by this thread I was finally able to obtain a current Metabo part number and (long but unnecessary story) ordered the condenser and received it a few days later. Interestingly, I note the "new" part was made in November 1993. Installation was a relatively straightforward affair and it was good to hear it going again. Such a long and drawn out wait for such a simplistic remedy. To all who responded, thankyou.






Incidentally, I decided to do a post-mortem on the older condenser, and here's what I found. Not sure what I was expecting, but it wasn't this.

Yes, it's just layers of foil, insulated by wax coated paper. When the layers are folded, they end up in an oblong cross-cut shape, and when they're rolled, they end up in a cylindrical shape. After years of use and submission to thousands of voltage spikes, a weak spot is bound to present itself. The spike jumps and arcs through the thinnest spot in the paper insulation. If it is a minor event, the molten wax seals the arc hole and the heat will not have been high enough to scorch the paper and to form carbon, which acts as a conductor. If the arc and the resulting heat are severe, the wax will vaporise or gasify, bulging the capacitor. When the wax is still able to seal off the leak and prevent further arcing, the capacitor will stay bulged but does not short-circuit any further. Bulged capacitors are sometimes known to survive for a few more years after such a mishap. But if the arcing is severe enough to melt several layers of foil and gasify enough of the wax, the capacitor may burst open and pop its contents.

When i buy a used machine, i always check the commutator, brushes and capacitor before i even plug it in. When the commutator and brushes have no burnt or frayed edges, the motor is usually okay, regardless if the capacitor is blown. When the cap looks bulged, i already replace it, just to be sure to have a reliable tool again.

Modern X/Y caps contain metallised polyethylene teraphthalate or polypropylene or polyester films (MKT, MKP, MKS types), with a much larger breakthrough resistance for arcing. The MKT polyethylene types are even "self healing", the plastic component melts the punctured hole between layers shut to prevent further arcing. The healing properties of molten PE are much more effective and reliable than those of molten wax. It is absolutely no problem (in fact it's an improvement) to replace a vintage wax paper capacitor by a modern plastic film one, as long as the rated voltage and Farad-value are the same. Nowadays is it even enough to replace an XY-cap by an X-only type, since radio receivers are less critical and dampen noise by themselves, and most TV-sets are cable anyway. I recently opened up a 1973 Festo orbital sander, which was already fitted with an X-only cap. Festo wouldn't have done that if it wasn't quite adequate for that machine.

greetings

gerhard