it | | il —_ wd | | fel = 58 roo OOc DQ e oc Q © i Et Ki | wa 6B eb EAU eae W INSTALLED IN THE R. E. OLDS HALL | Tame G.C. COLLINS C.R. STOUGH Shs = “+e “vr, ew owe eee ee ee ee 7 . . we wo ere CTT me ee ae : ° cee re —_ * mc 4 v ere , A AI “ *” PLACE IN RETURN BOX to remove this checkout from your record. TO AVOID FINES return on or before date due. MAY BE RECALLED with earlier due date if requested. DATE DUE DATE DUE DATE DUE JAB! fix? 405 6/01 c:/CIRC/DateDue.p65-p. 15 A General Test of the Otis Elevator Installed in the R. E. Olds Hall of Engin- eering. A Thesis Submitted to The Faculty of Michigan Agricultural College by \ - op 2 yy ’ Y © | G. c’ Collins C. R. Stough. Candidates for the Decree of Bachelor of Science June, 1917. THESIS A general Test of the Otis Elevator Installed in the R. E. Olds Hall of Engineering. It is well in a subject of this kind to first tell something of the history and development of elevators up to the present day. The first elevator was built by Archimedes in 236 B. C. It was operated by man power applied to a capstan revolving a drum on which the hoist- ing ropes were wound. Outside of this there was little development until 1850 when Geo. H. Fox and Co. of Boston built a worm gear elevator. From there on there has been a gradual development and today there is a type of elevator for nearly every class of service. The slow development of this means of transportation was be- cause there was no demand for it. There were no high buildings and consequently no means for vertical transportation was needed. But as civilisation advanced it became necessary to build higher buildings which opened a very large field for the development of elevators. One in- teresting feature is that the engineer has always been equal to the job and has built elevators which have met all needs in this class of trans- portation. One might think on first thought that as lonzgas the ele- vator safely carried the desired load nothing more need be considered, but if the best results are to be obtained it has to be designed for safety; reliability; durability; economy; control; comfort; speed; load and travel; and compactness. All of these are accomplished in 94914 many different ways which are beyond the scope of this subject and will not be discussed further. This test was run on an Otis Dual Control Elevator. It is aworm and gear type driven by a 15.5 Horse power 220 V. D. C. motor. The cage is about 6'10" x 6'3" and travels from the ground to the attic, a distance of about 54 ft. The mechanism is designed to lift a load of 3000 lbs. plus weight of car at a speed of 125 ft. per minute. The elevator is provided with two (2) lifting cables 3/4" diameter and four (4) 5/8" diameter counterweight cables especially adapted for elevator service. The car can be controlled either by push buttons or by the regular car switch commonly used in elevators. The series of push buttons in the car are numbered according to the various landings, and pressure on one of these will bring the car to the designated landing. The controller is an Otis Elevator Patented Full Automatic electro magnet controller which employs electro magnets throughout and thereby eliminates the use of all rheostats, slid- ing contacts or other easily deranged devices. With this controller the Current is gradually admitted to the motor enabling the operator to start and stop the car without shock or jar. This device is also constructed to secure the motor against damage from overload or excess current and is designed to prevent admigsion of more current.than is reqtred to perform the specified duty of the elevator. These devices are entirely automatic and independent of the operator. In addition to these buttons there is a safety button in the car which will stop the car at any point in ite travel. There is also a button outside each enclosure door which will bring the car opposite the landing provided that the doors are closed, and the car ks not in use, in which cage the call buttons will not work. Besides these there is an emergency call button located on the switchboard and connected with a push button in the car, There is an automatic non-interference system of control on the elevator which prevents the car being called by any one else until the person in the car dispatching it to a floor has opened and closed the car gate upon arriving at the floor designated. Each enclosure door is also provided with an automatic interlocking fixture to prevent the moving of the car unless the door is closed and locked. The regular car switch that operates the car without the push buttons is put in by a multipbe double throw kmife switch. When the car is controlled by the car switch the push buttons are inoperative, and the call push buttons in the halle become operative on the annunciator in the car, The annunciator is the electric single lock drop type consis- ting of a button for each intermediate floor, and single drops and buttons for terminal floors, The mechanism is provided with a slack cable switch designed and located to stop the motor immediately and prevent further unwinding of the cables shculd the latter become slack thru obstruction of the car in its descent. As stated above the machine is of the worm and gear type. The worm being cut from satk solid steel forging integral with the worm shaft and the gear being of phosphor bronze. The worm and gear are enclosed in an oil housing and run in oil. The end thrust is taken up by ball bearings which are backed by self alligning thrust blocks. The winding drum is connected to the worm wheel by means of a heavy iron collar bolted directly to the periphery of the drum thereby eliminating key connections between the drum and shaft, The worm shaft is directly connected to the motor, and these together with the worm gearing and drum are mounted on a heavy continuous iron bed plate. One of the most essential requirements of an elevator is safety. It has to be strong enough to safely carry the maximum load for which it is designed and there also has to be some sort of a safety device used to stop the cab for any reason it should start to fall. This particular elevator is provided with a car safety mounted under- neath the car frame which is connected by a cable to a safety speed governor which is designed to operate immediately in case the car attains excessive descending speed, either as a result of a broken cable, or any other reason, and causes the safety device to grip the guides se- curely and prevent further descent. Furthermore the motor is provided with a safety brake so arranged that when the elevator is stopped the brake is automatically applied to hold the car securely at the landing. This brake is accuated by spring pressure and is constantly in service exceptingwhen electrically released during normal operation of the ele- vator, end is therefore instantly applicd in case the current supply is interrupted from any cause. Besides these there is also an automatic device which cuts off the current when theelewator reaches the upper or lower terminal. The totel cost of the elevator installed was $3850.00. The work is along the nature of a general test of the whcle mechanism. However, nothing is attempted as regards the efficiency of the motor or the actions of the controlling magnets. The wiring dia- gram is far too complicated to be studied out here and so nothing is attempted along that line. The main idea of the experiment is to get a general idea of what the elevator is capable of doing and also to de- termine if possible how its performance compares with what is claimed of it in the specifications. Tests were run under loads varying from no load to full load, taking volts, amperes, speed of car, and time to accelerate motor, for each load. Pig iron was used to load the elevator, and was applied in 150 1b. increments, or as near that as possible. For each load the anm- peres required to start the elevator up and also those required to start it down, were taken along with the amperes required to run the car after it was started. Under light loads we found that when the elevator got near the top that the motor ceased to draw current and started generating, sending current back into the line. We concluded that it was the weight of the cables going over the pulleys that caused this. During the run a certain load was found which required as much power to run the elevator up as it did to run it down. This load is called the balancing load. The time required to go from one floor to the next was also obtained.for each load. The car was run from the basement to the top floor and back again, and the actual time of travel, between the first and third floor, and abso between the third and first floor, was obtained by means of a stop watch. This gives the time required to travel two floors and the time to travel one floor either way can easily be ob- tained from it. The time required for the motor to accelerate was obtained by ear and a stop watch. This was done by starting the stop watch as soon as the motor started and stopping it as socn as the sound of the motor indicated that it was up to speed. This was not done for every load because there was such a slight variation in the time for a small increase in load that one could not detect any appreciable difference in the time. Four or five readings were taken during the run and a curve was plotted which showed how the time of accekteration varied with a change of load. Another run was made taking the total time that elapsed from the time the button was pressed until the car stopped at the designated floor. This was done at no load, baianced load, and full load, using all possible combinations of floors. For instance we would go from the basement to the fourth floor and back again, from the basement to the third floor and back again, from the basement to the second floor and back again, from the basement to the first floor and back again, and then start in at the first floor and go to the fourth and back again and so on until we had taken all the combinations possible. The total time going each wap was recorded for each combination. This was done to show how the time of travel between certain floors compared with that between others. These results will show whether or not the car travels at a constant speed after it attains its maximum speed. Running Log of Time. Load Time from Time from Time required to los. Floor 1 to Flocr #3 to Accelerate Going Floor #3 Floor #1. Up_ 165 13.25 sec. 15.25 sec. 1.0 sec. 315 13.5 15.5 455 14.1 15 .5 605 13.75 15.2 755 13.8 15.01 1.2 907 14. 15.0 1060 13.95 15.0 1215 14.5 15.0 1355 14.8 15.0 1.25 1506 14.6 14.8 1654 14.7 14.8 1801 14.9 14.7 1946 15.1 14.5 1.55 2106 15.1 14.2 2254 15.15 14.2 2400 15.2 14.0 2551 15.4 13.9 Zed 2693 15.9 13.7 2850 15.9 13.4 3000 15.9 12.8 3.1 - 7 « Time required to Accelerate Going down, 2.0 sec. 1.9 1.9 1.6 1.3 Running Log showing total time from pressing button until car stops. Car Time with Time with Time with Travel No_ Load car balanced Full Load, B to #4 28.6 sec. 31.4 sec. 34.7 #4 to B 32.0 31.5 27.4 B to #3 C200 24.2 27.3 #3 to B 26.0 24.1 21.0 B to #2 15.0 16.8 19.9 #2 to B 18.1 16.8 14 4 B to #1 8 9.1 10.5 #1 to B 9.6 9.0 8.1 #1 to #4 21.5 24.7 26.5 #4 to #1 25.6 24.5 21.3 #1 to #3 14.8 16.8 19 #3 to #1 18.0 16.7 14.4 #1 to #2 8 1 9.1 10.4 #2 to #1 10.2 9.2 8.1 #2 to 14.6 16.3 18.1 #4 to #2 17.7 16.3 14.3 #2 to #3 8 8.9 11 #3 to #2 9.8 9 7.8 #3 to #4 8 9 9.8 #4 to #3 9.8 9 7.7 Running Log of Power Input. Load Volts Amperes Amperes Amperes Amperes to lbs Going Up Going Down to Start Start Down i 1 2 Up 165 220 25 -5 0 42.0 40.0 48 55 315 220 3.5 -3.5 38.0 35 .0 48 55 455 220 6.5 1.0 37.0 35.0 50 54 605 219 8.5 4.0 35.0 30.0 49 52 755 218 10.5 5.0 32.0 29.0 50 52 907 218 12.5 7.0 30.0 26.0 51, 52 1060 218 16.0 9.5 26.0 23,0 50 52 1215 218 17.5 10.5 21.0 20.9 50 52 1355 218 20.5 15.0 20.0 15.5 51 51 1506 218 23.0 17.0 17.0 15.0 51 51 1654 218 26,0 19.5 14.5 12.0 51 50 1801 218 28.0 21.0 12.0 9.0 ol 50 1946 219 30.5 24.0 9.5 6.5 52 50 2106 219 33.0 26.9 8.0 5.0 53 49 2254 218 36,0 28.5 6.5 4.0 54 49 2400 217 39.0 31.5 5.0 220 55 48 2551 216 43.0 36,0 eed 0.0 56 48 2693 218 45.0 37.0 1.5 82.0 57 47 2850 218 49.0 42.0 5 -6,.0 59 45 3000 218 52.0 45.0 0 =9,9 59 45 Tabulated Results showing car speeds for different loads. Load Lbs. 165 315 455 605 755 907 1060 1215 1355 1506 1654 1801 1946 2106 2254 2400 2551 2693 2850 3000 Car Speed Up Ft, per Min, 122.5 120.0 215.0 117.5 117.0 115.5 116.0 111.5 109.0 111.0 110.0 108.5 107.0 107.0 106.8 106.5 105. 102 102 102 Car Speed Down. Ft. per. Min. 106 104 104 106.5 107 108 108 108 108 109 109 110 111.5 113 114 115.5 116.5 118 121 126 Tabulated results showing average Power Input for different loads. - ji- Load Avg. Amps Avg. Amps. K. W. K. ¥. los. Going up. Going Down. Going Up. Going Down. 165 - 1.25 41 0275 9.01 315 0 36.5 0 8.04 455 3.75 36 .0 0825 7.92 608 6.25 32.5 1.37 7 15 755 7.75 30.5 1.69 6.70 907 9.75 28.0 2.12 6.15 1060 12.75 24.5 2.78 5.37 1215 14.0 20.75 3.06 4.55 1355 17.75 17.75 3.87 3.90 1506 20.0 16.0 4.36 8.51 1654 22079 13.25 4.96 2.91 18021 24.5 10.5 5.34 2.31 1946 27.25 7.75 5.94 1.77 21.06 29375 6.5 6.52 1.47 2254 6-82.25 5.75 7.05 1.31 2400 35.25 3.5 7.68 076 2551 39.5 1.75 8.55 38 2693 41.0 - .25 8.85 - .054 2850 45.5 - 2.75 9.91 - 99 8000 48.5 - 4.5 10.56 - 97 -12- Tabulated results showing foot pounds of work put in and its Ft. lbs. put into Motor Going down distribution. Load lba Going up 165 - 2,690 315 455 8,570 605 13, 900 755 15 , 600 907 21, 750 1060 28, 600 1215 83 , 700 1355 42,150 1506 46900 1654 53700 1801 58600 1946 66100 2106 72600 2254 78600 2400 86200 2551 97000 2693 103500 2850 116100 3000 124800 101100 91900 88700 80000 74500 68100 399300 50300 43250 88200 31700 29100 18950 15500 13700 7340 3900 - 545 -5820 -9150 Ft .Los.work in load carried 4460 8500 12280 16400 20190 24500 28600 32800 36600 40600 44650 48600 52500 57000 60800 64850 68800 72600 77000 81000 plus plus Ft .lbs.work on actual weight lifted 82740 28700 24920 20800 16100 11700 8600 4400 600 3400 7450 11200 15300 19800 23600 276506 31600 35400 39800 43800 Car moving twenty seven feet at normal running speed. atus she ) Ase Th rs ' 3 Pamere: —4 : ~4 | i. a Lt} ares 44 ups eee: , + i sane 288 eae See 4 ones ie n ee ees ‘ouee es et one ' LF HH eauet cane a ' | } | | t t ; } | ‘ a )Taesah | " Snes ; ea ee / ; | Bees bi / ' =" bay. e: | a zaus r ; afessstees } + + - | 1 ree : 4 pag | | EK ORBEA SD : : SB ra ; ew i re 5 a 2 Svirri ts eet 19 SEE RSOe CHa ee: t bas i eS 2m S514 AN SRLSSOWY hee EE Ss Spit — . eRDe8 6 ‘ es 95504 PUNSbx eas &: 998 pawn ee eae: ve ered: ime : f Tift re aan . t { : - ttt oem as 5 H pysrus: | a | ' | / ' e: och ’ | | | i oe a t ; | } I | ' Hl : | t t ; } | : } | ; ; | . ee! nt 4 poe Se } pa jtet > oo eee aaa eens! eeeese ev? a iene ee RTope: ap rm a ie } } besa, Sane bene: (+s eg! | } : | esc | | eeeets tee rs as : t aan ff pf fe ’ ee Dede SOK OVS Wes HAG EWE HNKs eae Be 3 i sebebes: Tete eeeel i i oy ee de i \ i cs » + i ++ ri a 5 : re ; anal ee 4 She TER sires? oh ‘tT PP cee een A772) 2) ae Be ot sad +++ bogons 6 rH anaet! oN a ag Le he i Hissitt A omer 3 abe, i aeseage eu pow Mitt ; T hy 2 ban ous ©! ater its sueascuve “th teecaeh bane ER Hy gpascaghae Seman ae Sea gaadan ocx; iguadgnend 2, lenses naneep ae Fr 2a BEB ag GueEeaueay Cuana tae: Saeeeseos tecuse eas ceensseats been Coutts. © faced Saaeee hea eat teas eonee. ¢Ge1) be! a eu beEg ss eee: ngeegees reeds. 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The curves showing the relation between car speed and load are interesting in that they show that the performance of the elevator does not come up to the guarantee. The car is guaranteed to carry three thousand pounds at 125 feet per mintue. ‘The car reaches this speed only on the lightest load, going up, and on the heaviest load, going up, and on the heaviest loads coming down. The average car speed for all loads is about 112.5 ft. per minute. The falling off of the voltage is very little and is not enough to warrant the low speed of the car. The time required for accelerating the car varies from about one second to about three seconds according to the load carried. On the very greatest loads the motor seexs to be slow in starting at all. Curve No. 3 shows the relation between the power input and the net load carried. Owing to the fact that the car is over balanced, there is no power required to raise the light loads. The point of intersection of the two curves gives the amount of "over balance " given the car for at that point the same amount of power is required to raise the car or lower it. This amount is 1380 lbs., a little more than would be expected from the fact that the general practice of counter balancing is to over- balance the car by about forty percent of the rated capacity. This would give a value of only 1200 pounds. "Curves No. 4 and No. 5 show the distribution of the work put in at the switch board. These values were taken for the car going from the first to the third floor,a distance of twenty seven feet. The weight carried in the car lessl380 lbs. (the amount of Overbalance) gives the actual unbalanced weight to be moved, This value times 27 ft. gives the foot pounds of work put to actually lifting weight. The foot lbs. of work supplied to the elevator to raise the car 27 ft. was found by takihg volts, amperes and time. The difference between the curve showing actual work of lifting and the input curve gives the third curve showing the friction and electrical losses. At point A on Curve Sheet #4 and at point B on Curve Sheet #5 there is no electrical loss as the motor does not draw current at those points. By means of these two points the friction curve was plotted on Curve Sheet No. 6. The friction curve taken from the combined electrical loss and friction curves of sheets #4 and #4 give the electrical loss curves of Sheet No. 6. Efficiency in the usual sense of power output divided by power input is hardly applicable to the elevator. The efficiency found in this manner would vary all the way from a negative quantity to infinity. Take the case of a very light load. Owing to the over balancing of the car no current is drawn after the car is once started. Power output over power input in this case would give an efficiency of infinity. Again take the case of a light load being lowered. The power output is nega- tive, yet due to the counterbalance, the motor draws quite a large current. In this case pover output over power input would give a large regative ef- ficiency. The. only way ther, to get an understanding of the economy of the installation or to compare it with other elevators is to study the input = load curves and compare losses directly. In conclusion it is well to note that the general public is interested more in the safety devices and fool proof construction of an elevator than in the economy of its maintainance and operation. This idea is emphasized by the fact that no data from similar tests could be found with which this work could be compared. NVI UO Mie mT