[LM240524], Letter from Thomas Alva Edison to New Jersey Zinc Co, James Bryant Tonking, March 29th, 1900
https://edisondigital.rutgers.edu/document/LM240524
Transcription
March 29th, 1900 Mr. J.B. Tonking, Supt., New Jersey Zinc Co., Franklin Furnace N.J. Dear Sir:-- In our opinion the greater height of your Elevator over those employed by us puts a considerably greater weight on the rope and this excess is the probable cause of the shortening of the life of the Ropes. Our ropes have run over three months and show no sign of any wires breaking. You can probably reduce the speed of elevator to 50 feet per minute by changing a pulley and this will cause elevator to probably run three times longer than it would at 150 feet per minute. We have one elevator that handled 70 tons per hour, running at 50 ft. per minute, which is the same kind as yours. We strongly advise this change of speed. This will give you time to order rope to get ready to put in new rope. We think, ordinary 19 strand steel hoisting rope will run about two thirds as long as the special rope; or you will probably have time to order the special rope. With enough men and rope splicers, the change can be made in about 48 to 60 hours, depending entirely, how the men are handles and the appliances used. We have always calculated that the rope should last one year, and think ours will, but the greater height and extra weight of your elevator has evidently strained the rope too much, and the only way, we believe, is to lighten the buckets and bottom wheel. If you desire, we will get out a plan for lightening the buckets and other devices to diminish the weight, and then you can change gradually, so that under your conditions, we think the rope will last one year. Yours very truly, Thomas A. Edison