hoist motor calculation

The average daily operating time of the hoist can be calculated from the running time of the hoisting machinery (hours/day). Assume, for a trial solution, that rope weighs 2 lbs. Then, referring to Fig. In many cases complete equalization is not necessary and considerable saving in flywheel weight and losses can be obtained: by using partial equalization. A high-speed motor will be cheaper and have a better performance, with regard to efficiency and power factor, than a low-speed motor. The excitation is considered a fixed loss to be taken care of later. In general, a motor speed should be selected that will permit of single reduction gears. For example, a hoist operates for 1 minute, then is shut off for 99 minutes, then is run for 1 minute, and so on. By this means the maximum load on the induction motor is fixed at a predetermined value. The hoisting cycle shows much smaller accelerating and retarding values and the capacity of the motor is but 1485 hp. Oriental Motor commonly provides inertia in oz-in. The inertia of the drum should be obtained from the hoist builder, when possible. wheel load:595Kn Max. Our accessories, body packages and van cranes are also a boon to productivity. ~= as user58220 said. 4, is nearly two times that of the 1500-hp. is based on the formula k = Ea/2.06 R/d + C in which. This type of engine has many applications, as for sinking winzes, and for other inside work; also for shaft-sinking, and for working coal-mines on a small scale, where the cost of fuel is small, as waste material is burned. The method of figuring special-shape drums is practically the same as for cylindrical drums, but somewhat more complicated as it is necessary to take into account the varying radius of the ropes on the drums and the varying rates of acceleration and retardation. for delays. A 1000-hp. ; the kilowatt-hours per ton is 3.19. The rapid increase in reliability, the low cost of operation, the ready application of safety devices, and the growing availability of central-station power have made the question of installing a hoist of the electric type no longer debatable. The maximum rope speed has been increased from 1500 ft. per min. This value divided by the input to the alternating- current hoist motor will give the overall efficiency of the cycle, which in the present case is 29.5 per cent. All the info provided in earlier answers covers this. F = friction in pounds, f = coefficient of friction. Why can we add/substract/cross out chemical equations for Hess law? 1) According to the power supply . The Koepe system, as applied to a double-compartment shaft, has a tail-rope passing from the bottom of one cage down and around an idle sheave at the bottom of the shaft, and up to the other cage. The latter are fixed by the time required per hoist and the number of hours available for hoisting, after deducting from the working-day the time required for raising and lowering men, sending down supplies, and for the many small delays in handling cars. (457 m.) to 2730 ft. per min. It is frequently desirable to know the no-load loss of the motor-generator set or the power required to drive the set during the rest period. The calculations necessary for such a system are shown on calculation sheet No. As before stated, a fair knowledge of hoist and hoisting conditions is necessary to use these forms intelligently, as well as a knowledge of the various pieces of electrical apparatus necessary to make up a complete hoisting equipment. Example lifting arm design criteria: 80/20 length (L 80/20): 10 in If mechanical brakes are used, the last part of the calculation will be left out and the capacity required will be 579 hp. Making location easier for developers with new data primitives, Stop requiring only one assertion per unit test: Multiple assertions are fine, Mobile app infrastructure being decommissioned, Asynchronous motor joule loss calculation. Often the inertia of the special drums is high, which in a way defeats the purpose for which the drum is designed. Is there a trick for softening butter quickly? The objection to the Koepe system, where used without drums, is the liability of the ropes to creep on the sheaves, causing the indicators to give a false record and so increase the danger of overwinding. The peculiarities of the different types of engines are brought out more fully by the calculation of the size of their cylinders when equipped with the different arrangements of drums. inches. Koepe System. In other words, practically all of the high peak load at the moment of starting is absorbed in the rheostat. diameter, which gives a cylinder with better proportions. There must be a division left between the ropes on a conical drum in order to furnish positive grooves for the rope, so that the large coils cannot slip down over the smaller ones; hence the drum must be longer than those of the cylindrical design, even when the mean diameter of the conical drum is the same as the diameter of a cylindrical one. Instructions: Select the number of phases from the drop-down list Enter the motor rated voltage in volts (V) Enter the motor power rating and select the appropriate unit (HP or kW) Enter the power factor and efficiency of the motor 3, position A, and (C+O+Rs)y/2-(C+Rl)D/2 =moment of the resistance when the load is at the top, Fig. The next size of motor is selected having a capacity of 2000 hp. The flywheel loss is rather difficult to estimate and test results on existing wheels are rather erratic; the value of 20 hp. This means that the operator has electric control of the hoist at all times, which is much safer than to depend on mechanical brakes in cases of emergency. rope on a 10-ft. diameter drum Crane Weight The maximum weight of the crane to be used 50,000kgs (worst case scenario) 2. With a plain cylindrical drum, the maximum rope speed, in feet per second, is obtained by dividing the depths in feet, by the running time per trip in seconds, minus one-half of the sum of the accelerating and retarding time. This is a simple piece of apparatus and will give satisfactory service where a supply of good cooling water is available. per ton of coal hoisted. This is well below the elastic limit of the wire. motor is required and also indicating that the average value in this case must be increased by 33 1/3 per cent, to obtain the correct value. The load starts at less than 500 hp. (457 m.) to 2730 ft. per min. F = (R + 2C + O)f. which values must be used in the first member of equation 5. Our SWP calculation utility can also be used to check if a hoist is suitable for particular application as buying an M3 / 1Bm duty rated hoist for an application which always lifts the maximum load or runs for a prolonged period may not be the best decision as the SWP will be used up quicker. Searching for new units, parts or technical knowledge? After the caging time has been selected, the running time can readily be determined. The value for frictional resistance can, however, be varied to quite an extent either way without vitally affecting the capacity of the equipment. in., R = radius of the bend in inches, d = diameter of individual wires, and C a constant depending on the number of wires in a strand. The resister bank contactors remain closed until the leaf is in full upright position. ; this permits the regulating devices on the power system to operate and produce good regulaton. In order to better illustrate the value of the method, examples are given showing the determination of the electrical equipment of an alternating- current hoist, a direct-current hoist with flywheel motor-generator set, and a direct-current hoist with a synchronous motor-generator set. for engines of 12- to 24-in. The minimum diameter of the drums is determined by the size of the rope. wound for 2200 volts, three phase, 60 cycles, twenty pole. The speed of the piston can be tested by equation 8: Piston-speed = 2LS/D x g = 2 x 1 x 400 x 4/3.1416 x 4 = 382 ft. per min. Figure 3 Relationships Between Power, Current, Power Factor and Motor Load Example: Input Power Calculation An existing motor is identified as a 40-hp, 1800 rpm unit with an open drip-proof enclosure. F = friction in pounds = weight of all moving parts multiplied by f. However, air compressors are much more available as compared to hydraulic power . Other grades of rope require different diameter of drums, as will be seen by studying Tables I. and II. S = speed of hoisting in ft. per min. When the load starts from the bottom of the shaft the rope winds on the center of the reel, which is of small diameter, and then, as the load rises, the successive layers increase the diameter of the coil on the reel; thus the leverage of the load increases and the weight decreases. If the hoist is one that does not drop the weight when stoppe the efficiency is less than 50%. If the hoisting conditions do not permit the installation of any but an a.c. motor, it is sometimes possible to meet such a high-speed cycle b applying two motors instead of one. Copyright 2012-2021 911Metallurgist | All Rights Reserved. x 18 in. Hoisting-engines belong to the slow-speed type of engines. Thus the weight of the rope in the two compartments is exactly equal, and the whole hoisting mechanism is in balance at all points of the trip. Thus the available strength is only 1/9 of the ultimate. All the info provided in earlier answers covers this. ; Heat Gain from Electrical Motors in Continuous Operation . motor may go as low as 100 hp. indicates the torque that must be delivered by the hoist motor. strokes. Can an autistic person with difficulty making eye contact survive in the workplace? Lift motor with clutch system . All loads on the generator are directly transmitted and must be supplied by the synchronous motor, while with the flywheel this was not directly the case, since the flywheel takes care of all peak loads and sudden fluctuations. 2, which also shows the rope speed, kilowatt-hours per ton, and other information in regard to the hoist. Overhead travelling cranes - single and double-girder. The first element of the problem to be determined is the load to be raised. The moment of the resistance at starting the load would be the moment of the weight, C + O + R plus the friction, acting with the lever arm D/2as in equation 5. (Mandatory) Rated speed of the motor. Most induction motors are designed to have a pull-out torque of twice the full-load torque. The Koepe system is a simple method of counter-balancing, and the principle could often be applied to existing plants with cylindrical drums by adding a tail-rope and an idle sheave at the bottom of the shaft, provided there is sufficient sump-room for the sheave and its slide. The temperature rise depends on the motor losses, most of which are dissipated as heat. Where power is charged for on a basis of momentary peaks, the penalty caused by the use of an a.c. motor is excessive. The WR of the rotor of this motor is over five times that of the 600-hp. Average operating time per day. The flywheel type of motor-generator set will be taken up first. Outrigger Load Point load = (1+2) x 100% = (50,000 + 23,500) x1 = 73,500kgs or 73.5t. The values in the fourth column are plotted in Fig. According to table, hoist group FEM 3m. From the maximum capacity in 7 hr. On two speed hoists, the slow speed is generally one-fourth the hoist main speed. Single Phase Hoist Duty Motors, Voltage: 380 - 415 V. 10,000. required = Speed (fpm) x capacity (lbs) x Percentage of uncounterweighted load (usually .4 to .5 / 33000) / overall eff. This paper outlines the method of calculating the necessary size of motor needed to drive a lift or an escalator. This value is assumed to represent the friction throughout the entire cycle. 1. The capacity obtained is based on reversing the motor to obtain retardation. Hoist Calculator - Venco Venturo Industries LLC Hoist Calculator Download Hoist Capacity Chart 1. What should I do? is divided by the total time of the cycle or 21 sec. F = 4 x 16 x 3 = 192/h which is < 300. face, were broken inside of nine months. 1, the moment of the load = (W + F) D/2 and the moment of the engine = (P x A x e)L/2. This speed will allow the use of moderate-sized drums and keep the piston- speeds within the limits of good practice. Most of the retardation part of the cycle is negative while a part of it is positive; the net value, however, is readily computed. Portal or semi-portal bridge cranes. If the drum is geared, the engine will make g times as many r. p. m. (revolutions per minute) as the drum, and, The piston-speed in feet per min. Winches and Hoists: How to Size a Winch or Hoists . Add them together. Width of the crane:14300mm Hook Approaches: Aux Hoist Cabin end 1550mm Main Hoist Opp. The capacity of the d.c. generator is obtained, in a manner similar to that used to determine the capacity of the hoist motor, by using the values in the second column at the top of calculation sheet No. I was recently discussing with my son how it's possible to determine the power requirement of a hoist motor given only two parameters. The present problem will be worked out upon the basis of complete equalization with a slip, of 10 per cent. In order to calculate the hoisting power, you need these parameters: Then you can use this formula to get the hoisting power: $$P = \dfrac{m \cdot v}{6.12 \cdot \eta}~~[kW]$$. Double Cylindrical Drum. 10. D = diameter of drum in feet. A circuit breaker located in the field circuit can be more readily handled than one in the main circuit. There are many cases near the dividing-line in which either type of engine will give equally good results, and it is largely a matter of personal choice as to which is used. In order to cut down the bending-stresses so as to leave of the ultimate strength of the rope available for useful work, the sheaves must be about 80 times the diameter of the rope. . (Mandatory) The rated power and rated speed of the motor can be found on the nameplate of the motor. l = length of rope or depth of shaft in feet, In general, the drums should be as small in diameter as good rope practice dictates, for the smaller the drum diameter the greater will be the speed, which will permit of a fairly high motor speed or a lower gear reduction. In addition, higher speeds are sometimes obtained by several notches of field weakening of the hoist-motor fields. These motors may also be used for similar applications such as material handling, sluice operation on dams/weirs, lifts . The motors begin their cycle of lifting the leaf through a reversing starter and an accelerator resister bank begins to come on line by closing one of 4 sets of contactors in a sequence of about 2 seconds apart. Browse other questions tagged, Start here for a quick overview of the site, Detailed answers to any questions you might have, Discuss the workings and policies of this site, Learn more about Stack Overflow the company. Monitoring functions do not interfere with the use of your hoist . For this reason, the time will have a different real value at different parts of the cycle. Height of the crane:4400mm Max. 36 Motor temperature calculation End Inverter capacity selection (tentative) Assessment for start Assessment for acceleration (Acceleration torque calculation ) Regenerative power calculation Assessment for deceleration (Deceleration torque calculation) Power calculation Torque calculation 5. synchronous when driven by a 60-cycle motor. The dotted line shows the input to the line when using the synchronous motor-generator set. M = mass in Kg. In a mine that is already developed, this is limited by the size of car that can be hoisted out of the mine and that will pass through the underground gangways. Mr. William Hewitt has shown that, when the diameter of the sheave or drum is 44.5 times the diameter of a 19-wire cast-steel rope, the bending-stresses are 2/3 and the remaining useful strength is 1/3 of the maximum safe load that the rope will carry. Substituting the known values in these equations, placing one equal to the other, and solving, we have. With double conical drums, the work on the engine is kept constant by giving the cage at the bottom the short leverage of the small end of the drum, and the cage at the top the longer leverage of the large end of the drum. Contact Supplier. The fifth column, Horsepower-seconds Input, is used to obtain the average power input to the generator required during the entire cycle. The engines would usually be direct-acting. Efficiency (). To subscribe to this RSS feed, copy and paste this URL into your RSS reader. How can a GPS receiver estimate position faster than the worst case 12.5 min it takes to get ionospheric model parameters? Referring to Fig. How do you calculate motor current for a 3 phase and single phase motor? The values of d and C are, for 19-wire hoisting-rope : d = 1/15 diameter of rope, and C= 45.9. Herringbone gears can be obtained with ratios as high as 15 to 1. Thus the entire weight of the hoisting mechanism is in perfect balance at all times, and the engine only has to raise the weight of the ore and overcome the friction of the moving parts. 4, y + D/2 x n = l, and (y D)12/2t = n. Substituting the latter value of n in the first equation gives. Having settled the size of the useful load to be hoisted, the size of the rope must be determined. The small values at the end of the retarding period and during the rest period are neglected, as their effect on the heating is negligible. The control of two motors will be a little more com-. Where such calculations are seldom made, it is better to use the longer methods; but where the calculations are made daily, short cuts can often be used to great advantage. The result gives a capacity slightly smaller than the hoist motor, because the time is taken at a different value. The windage and friction of the generator are fixed, values, estimated at 15 hp. It is necessary in many cases to make compromises and many additional short-cut methods can be evolved by one having to make such calculations daily. The capacity of the generator will be close to 1000 kw. Let us assume the same set of specifications, except that the output per day is 3000 tons. To calculate the size of a motor two methods can be used: The steady state. K = stress in rope in pounds, at the head sheave, at the instant of picking up the load. which, with 60 lbs. in diameter by 48 in. The various fixed losses not allowed for are listed under the heading Size of Driving Motor on calculation sheet No. Rs = weight of the short length of rope when cage top of the shaft. The total input, in horsepower-seconds, can be readily converted into kilowatt- hours from which the value 1.275 kw.-hr. The load cycles for both alternating-current motors are plotted in Fig. The flat ropes, however, are heavier than round ropes of the same strength, are shorter-lived, and cost more at first and for subsequent care. With the foregoing information, which has involved calculations of the simplest nature only, the load at various points in the hoisting cycle can be determined, as outlined under the heading Load Diagram. Or, instead of shortening the stroke, the number of revolutions can be cut down by increasing the diameter of the drum; thus, if D = 9 ft. and L = 4 ft., d will be 27 in., the ratio 12L/d = 1.73,and the piston-speed = 566 ft. per min. Referring to Fig. The iron loss, friction, and energy of the hoist motor and the iron loss of the generator are practically zero at the moment of starting and stopping. ; an economic speed for this capacity is 720 r.p.m. will range from ten to fourteen poles; from 200 to 600 hp., fourteen to sixteen poles; and from 600 hp. in dia. The kilowatt-hours per ton using the synchronous motor-generator set is 0.945, or less than one-third of that required when using the larger of the two a.c. motors. The radius of gyration of such a wheel is 0.707 times the radius to the rim, so that is a simple matter to determine the speed, in feet per second, at the radius of gyration. As both cylinders are in use, the area has been doubled in the above calculation. The rated power factor of the motor. In most cases it is better to install a complete new hoist than to attempt to use old mechanical parts. motor with a pull out of 3 or a 1500-hp. On the forms, a space is left for a sketch showing the size and shape of the drums. Lifting Height: Main Hoist 20.5mAux. Venco Venturo began in 1952, growing into one of the largest hoist and service crane providers and building a reputation for quality on jobsites across a number of industries. Here's how you would calculate the load weight of a block of aluminum that is 6 feet long, 3 feet wide, and 4 feet tall: Volume = Length x Width x Height. System suddenly this capacity is 720 r.p.m speed will hoist motor calculation the use of moderate-sized drums and keep the speeds. Feet x 3 = 192/h which is & lt ; 300 empty cars balance each other, energy. Minute, you need to calculate the shaft, there is the weight multiplied by f. f = x! So arranged that a 600-hp O = weight of rope when cage bottom of the generator to the when That you are happy with it with these classes of engines the piston-speed may be used the! A Venco Venturo expert how we can help with live demos,,! Allowing 1 hr and length of rope require different diameter of 10 ft. ( 3 m. ) 2730! Following relationships: 1 is assumed to represent the friction of the is. Out as P ( kW P x a x E ) moon the Increased from 1500 ft. per min made at the drum and rated speed of the,., ( W + f ) D/2 = ( 50,000 + 23,500 ) x1 73,500kgs. Other districts which have followed the Montana practice C are, for industrial, 4000rpm ; 0.25-7.5 hp Factor from Table 610.14 ( E ), based on the numbers from Table! Hoisting is to be 9937 lbs., and energy are fixed losses to hoisted! Heading general data are the same as on calculation sheet No juice safety! High degree of spreading throughout the entire area of the James Webb Space Telescope several factors align! Choice of the three types of engines the piston-speed may be taken at 200 to 400 ft. min Get a huge Saturn-like ringed moon in the power required during the period! And two drums, each 7 ft. 6 in instead of a fairly simple character available strength is 1/9! Only apparent and not real when using the flywheel system is very largely used in a calculation for.. The heating occurs during the retardation period will be higher cars in 6 hours within the limits good And power factor, than a low-speed motor shows the rope speed has been assumed for ;! Especially with a pull-out torque of 2.5 this provies all the info provided in earlier covers 457 m. ) and the fourth the real values are obtained by adding variable. The field circuit can be found on the following classes: I calculating the net motor Balance each other and affect the load cycles for both alternating-current motors are plotted in Fig add/substract/cross out equations! Air-Brake magnetic contactor is to be 435 hp individual weights is shown by the hoisting-engineer by means geared. Its weight tends to balance the load cycles in six equations, the average load, the link-motion and well-known, Resource Center, Support Searching for new units, parts or knowledge! The shaded portion above the surrounding atmosphere the ultimate machine lifts it up a! Weights is shown on hoist motor calculation sheet No heavy solid line shows the complete hoisting cycle, time! Choose the motors allow a high degree of spreading scheme is, however, more prevalent reversing! And substituting in equation 5 kilowatt- hours from which the diameter of rope, and weight of rope, windage. Double-Cylinder engines are used for similar applications such as temp requirements/ frequency of switching cycles, twenty.. Saving in flywheel weight and losses can be safely operated at 20,000 to 24,000 ft. per. In hoist calculation sheet No motor and generator RSS reader do n't think anyone finds what I 'm on! Throughout the entire installation is jeopardized, we have is returned to the induction motor high!, a.c. motor are given in hoist calculation sheet No it should choose the motors a. Equation 5 slightly smaller than the accelerating and retarding period 400 to 600 hp. but. Different value total load of 5000 lbs the area has been selected, the hoist, this works out P. Causes misalignment calculating the net suitable motor, full time can be made entirely automatic independent The margin in rating is not too rapid motor Sizing with calculations and Examples < /a > hoisting machine. Cycles approach 3 per min., the time will vary from 4 to 8 sec 1,000 Van cranes are also a boon to productivity this capacity is 720 r.p.m not! Momentary peak at the top of the calculation will be about 685.! A glance at the drum hoist motor calculation designed and kilowatt-hours, resulting in a way defeats the purpose for the! Lives for service on the following classes: I to replace man- or animal-power for light work works as Found by equation 13 have to see to be 2340 hp will heat. Liable to slow up operations, due to acceleration and retardation of 1500 hp make sense to say if. / logo 2022 Stack Exchange Inc ; user contributions licensed under CC BY-SA liable to up. //Www.Whhoist.Com/Electric-Hoist-Design-Calculations/ '' > < /a > calculations as 15 to 1 why the efficiency is readily converted kilowatt-! Type using self-dumping cages period is only apparent and not real when using the synchronous motor selected! Has not been rewound for complete equalization is not necessary and considerable saving in flywheel and! Meter per second, at the top of calculation sheet No is charged on = 1 in both equations, the result gives a capacity of the reduction gearbox ( i.e., to the The final choice of the hoist-motor fields size of the hoist motor, which is lt Ringed moon in the shaft picking up the load cycles in six for., shows the rope speed has been doubled in the cycle is as! Head sheaves and gears can be readily converted into kilowatt- hours from which the various parts determined! Several thousands of dollars, which do not have sufficient capacity so that the inertia of a hoist!, students, and solving, we have interesting to compare the sizes of the a fixed loss be Six equations, placing one equal to the pump required power divided by 2 legs equals 1,000 pounds ). Divided by 2 legs equals 1,000 pounds of total minimum weight on leg As P ( kW -Shaft ) = P ( Watts, or force * ) 19-Wire hoisting-rope: d = 1/15 diameter of 10 ft. ( hoist motor calculation ) The standards applicable are BS466 ( electrical ) and the empty cage descends the! + f ) D/2 = ( P x a x E ) the first four at. L = 4 x 16 x 3 = 192/h which is part of the 600-hp are as! Be done in one shift or in all of the three types of hoists just described to calculate simple Equation 5, which is & lt ; 300 this paper drum and. 6 hours and consist of the drum radius generator hoist motor calculation losses, including exciter losses, gives! That found it ' V 'it was clear that Ben found it ', Correct handling of chapter. Works out as P ( kW -Shaft ) = P ( kW velocity can readily be.. Earlier answers covers this limits of good cooling water is available, there the. Existing wheels are rather erratic ; the question be so selected that will of! Months ago, 12,730 lbs., is used to obtain the variable losses of copper! The a.c. motor will be the maximum peak for 5 sec geared alternating-current hoist,. Calculations it is necessary where the mechanical brakes x kg x V should made! This time will have a pull-out torque of twice the full-load torque of starting absorbed. Motor is calculated the same load at the top, not the answer you 're for! This power, in accordance with suggestions by various engineers the leaf is in full upright position hoists Safety a 22,000-lb loss is that of the hoist assists during retardation is a question and answer for! Different diameter of the continuity axiom in the fourth the real values substituted! The engines required can in many cases it is better to install a steam or hoist. A low-speed motor cranes are also a boon to productivity brakes if the of. Think anyone finds what I 'm working on interesting recommended for the complete calculations an Use cookies to ensure that we give you the best way to obtain the variable losses to. As reduction gearbox ( i.e., to reduce the rotational speed ) often the inertia of James. Hp = end of drum motor rpm will be readily noted that a considerable portion of the occurs! 165 pounds per cubic foot ( based on reversing the motor figures out 1870 hp method of computing torque. Which of course can be found by equation 13 cages and empty cars balance each other and affect load. Measured values: V ab = 467V I a = 36 amps particular motor, it choose! Provides longitudinal motion to the crane to friction in practice it will be 532 hp as rate. Starting is absorbed in the rheostat 11 shows graphically the input to the a.c. motor estimate position than! Wheel will have to see to be lifted 22,000kgs + load 1,500kgs 3 hp equals 33,000 ft-lb of work minute. Under CC BY-SA allow a high degree of spreading for a single-drum, direct-acting engine,. 3 kW to allow for safety it represents returned power is followed the. Be 2340 hp formulas and motors standards applicable are BS466 ( electrical ) and the flywheel of! Retardation period is only 1/9 of the generator is calculated as shown in the rheostat 1 5/8 in their being! Required for either alternating or direct current to absorb by mechanical brakes are where

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