Home Forums General Discussion Technical Questions Winding drum counterweighting?

Need help on a problem with a 20's vintage winding drum. A previous company came to the job and re-roped the car and counterweight. It appears to be correct. This is a overhead drum, single counterweight,straight over...except for the drum. My problem is that the car will only pick 800 lbs. on a 2000lbs capacity car. The motor was gone through and they say is ok. So I thought it was the machine binding in the up run. By the way the down run works great. So I picked the brake to see if the car would drift up....the car actually went down. I am baffled!! Is a winding drum not balanced at 40-50% like others? By the way nothing that I can see added to the car and the counterweights do not seem to have been disturbed. This company wants to use this car as a freight if I can get it to pass the 5 yr test. Any thoughts on the issue?

I would say you are under counter weighted. Many Drum Machines had 2 sets of counterweights, one to account for the weight of the car, and then another stacked on top to account for the load. If the car weighs more than the counterweight you have 2 choices. Add more counterweight and probably a bigger motor. You must also account for the Machine Beams and the overhead structure for the extra load. Or upgrade to a new Elevator. I personally would run away from anything except a Mod.

Take an AMP reading on the motor MT car down and see how close you are to full load AMP on name plate. It should be close to FLA with the problem your describing if it is not balance properly. But that is ALOT of weight to be off by if the car stalls with 800lbs or does it blow overloads? Either way drifting down with a brake pick tells you something is way out. Are you sure you have the original sling and platform? Cab ? I'm thinking your 2000 lbs off somewhere.

I would agree that i am under counterweighted. There is no second counterweight on this style....I do have one like that on my route. I am wondering about the motor part of it. I have taken meter readings on the motor and they are 15 amps on all 3 legs in the car down an d 25 amps on all 3 legs in the car up. Which also says that the car is too heavy. This is the original everything on this elevator. As I said previously the motor was gone through twice and they say that its OK. Not sure if this is how it was originally set up and the motor was just stronger then? It does not blow the overloads in either direction.

You are absolutely under counter weighted. If you pull more amps empty car up you do not have enough counter weight. To see how much, you have to either somehow, remove some weight off the car, or add some to the counter weight. When you achieve balance,the amps will be the same in both directions. That will give you some idea how much weight you have to add to the counter weight to have the weights be 40%-50% heavier than the car. These old elevators were not as precisely engineered as you would think. That said,who ever was doing the 5 year cat test was fudging the paper work.

I agree 100% but how the heck did this thing ever run to begin with? How the hell am I going to make it pass now? I can't really add that much weight to the cw because I would be afraid of structural issues. I was thinking of redoing the cab with lighter material for walls in order to remove some weight. Right now they are steel on the bottom 2/3 of the wall and wire mesh steel on the top 1/3. Don't know if I could redo this with something lighter? Its a wire mesh for a car top so I don't think I can change that. I could replace some of the cast CW's with lead but not enough to take care of the whole problem. Any more suggestions?

I dont know about your state but in mine nothing says you have to pick the load just stop it with the safties,and hold 125%.that doesnt fix them problem but ive seen cars with capacity reduced

Your choices are reduce capacity, or Modernize. The unit is 90 years old. It has served admirably. Give it a salute and replace it.