The Dover Generator, or as I like to think of it, “The Teenager” of MG’s
Let me try and explain that as I believe it will help the Mechanics that have not the experiences with it as I have had.
While many mechanics like myself have come and gone, there are many more who have inherited these units and have to try and keep them “behaving”. Saying that, I would like you to think of the development of the Traction elevator like this. The Grand Daddy Otis got into this business from the traction end. They have a much better and quality MG. Dover, on the other hand had to play catch up as they got into the business on the Hydraulic end and never caught up. The Dover generator is not a bad one, it’s just has some charatoristics that cause it to “misbehave” on occasion. That’s why I call it the Teenager of MG”s.
Let me mention some things that contribute to this misbehavior.
Firstly; the resistance to ground of the armature is too low. There in no other way to say it. If you meg one that has been in operation, you will probably find it far below one meg. Maybe like one thousand to two thousand ohms to ground. But, strangely, it still works pretty good.
Secondly, the brushes that are sent in it are SA-45. It’s a soft brush and produces much dust which causes the resistance of the armature to sink even lower as the dust penetrates the windings of the armature.
So, with this problem, one must routinely try to blow the dust out. Very messy stuff. The entire room suffers from black dust and when you get home, your spouse looks at you in fright and asks, where in the hell did you get so black.? But Sadly, if you don’t try and keep the dust from accumulating, you will eventually have more trouble calls for leveling issues.
OK, so we put in a harder brush, right? Been there done that, they eat the commentator and now you have copper dust with the black dust. But I have found that there is a brush that will produce much less dust and not eat/sand the commentators. It was produces by a good brush company and costs more than most but it is worth the couple bucks to keep your Dover MG in the pink. It is called the E-41/C brush. The C part is a component that Helwig added just for this generator.
http://www.helwigcarbon.com/
Thirdly, the Dover MG can and will be susceptible to environmental effects like the changing of the season, fumes from the surroundings, this sort of thing.
The outcome of the behavior of this MG is critical in nature as it produces leveling problems with the elevator. Nothing more critical than that. Law suits galore. Customer loosing confidence in you and your company. Yea, I’d say the E-41/c is worth the money.
Last edited by mjm; 10/07/16 04:13 PM.
