Beninca Bob50ME Gate Operator

[awemawson]

The other day my electric gate actuator popped it's clogs - all a bit embarrassing with visitors on the wrong side now it's been growling for a while and I've been keeping an eye out for an economic spare, but none had surfaced. It tuned out that the final failure was in the starting capacitor for the 240 volt AC motor, and I jury rigged a replacement in as a temporary expedient - it was too large physically for the cover to go on but at least the gate worked.

Now I'm sure that the capacitor failed because the motor was growling and taking too much current through the capacitor so time to bite the bullet and buy a new actuator - only £384.40 

So having installed the new Bob50ME on the gate yesterday today it's time to investigate the faulty one. Mechanically reasonably straight forwards, a motor (that can be reversed by swapping where the start cap goes) drives a reduction gear train that incorporates a dog clutch that then drives the screw. A nut on the screw is attached to a pivot on the gate, and Bob's your Uncle - or in this case Bob50ME 

Pulling it apart wearing rubber gloves, as I've kept it as well greased as possible (not everything is accessible when on the gate) it is obvious that the wear is quite significant in the screw / nut combination, and in the gear cluster.

This gate was installed six years ago, and according to it's controller when it failed it had opened and closed 28,495 times in those years, or eleven times every day on average. Or 1.349 pence per open / close cycle just on the cost of this one item !!!

So are parts available? Well yes it turns out that they are but at a price - £195.60 including the VAT 

Repair or not to repair - that is the question - slight pressure applied to parts department and they are 'looking at the pricing' and coming back to me !

[awemawson]

The dealer came back to me with a slightly better price (£146.40) on the spares so rightly or wrongly I have ordered them.

But I took the precaution of powering up the motor on the bench and running it in both directions to make sure the growling wasn't internal - glad to say it ran very nicely and looking at those worn gears I'm sure that they were responsible for the lion impressions.

At least then I will have a known compatible working spare on the shelf to use in another six years !

[Brent Crude]

Any chance you could make the gearbox a more ‘sealed’ unit so you could have more of a grease bath in there to help prevent wear?

[awemawson]

The problem is that the entire works are sandwiched between two die castings, with the bearings all housed in  half circles, one half in each die casting so almost impossible to make oil / grease tight. I may be able to fit grease nipples leading thin copper pipes to each gear set.

[PekkaNF]

Well, you have 3D printer and CAD? Maybe to plastic containment compartmens for grease filling around the gears?

[nrml]

Would it be worth the effort of making (or buying) one or two sacrificial gears in a lubricant impregnated plastic material?

[awemawson]

The one on the end of the operating screw is double sided with only the out side actually used so could be reversed - looks to be only retained by peening with a spline coping with the torque which will be very considerable. The actuator has a push of 3500 decaNewtons (that's nearly 8000 lbF)- I don't think plastic gears would cut the mustard.

Imagine pushing a 12 foot heavy gate with your hand only about 12 inches away from the pivot when a howling gale is pushing in the opposite direction, and this gate does face the prevailing winds. Also a bit of snow on the ground gives quite a load !

[awemawson]

I was just picking up the 'phone to chase the spare parts when the DPD man brought them into the farm yard!

So, insert screw, nut, gear train, clutch locking mechanism, and motor - grease everything in sight including me, and screw the upper and lower shells back together avoiding trapping the wires. . . . ah . . that's what that little ty-wrap was for !

Once back together I tested it running in both directions - no more grinding noises 

Then wrap it up in the genuine Beninca box that the new actuator came in, and think where it can be kept for the next 6 years when the one I've just fitted fails