This, following the same form as equation 5, gives: Taking as an example the one used for the engine with double cylindrical drums, depth of shaft 2000 ft. plus 33 1/3 ft. to head sheave above landing, S = 2000 ft. per min., O = 5000 lbs., C = 5000 lbs., Rl = 6100 lbs., Rs. X 2 +1500 X 2 lbs. ; Heat Gain from Electrical Motors in Continuous Operation . With an a.c. hoist, this is accomplished by automatic acceleration and the well-known safety devices supplied by the various hoist builders. F = friction in pounds, f = coefficient of friction. Please tell me I'm right? Then the motor rpm will be: 43.4*34.5 =1497.3 [1500 rpm rated]. From the hoisting cycle, the kilowatt-hours per ton and the overall efficiency of the hoist can be estimated, as shown under the heading Input with Rheostatic Control. How can a GPS receiver estimate position faster than the worst case 12.5 min it takes to get ionospheric model parameters? Such a flywheel can be safely operated at 20,000 to 24,000 ft. per min. This speed will allow the use of moderate-sized drums and keep the piston- speeds within the limits of good practice. These two parameters are the weight to be lifted (150 kilos),and the speed at which they are to be lifted (3 meters per second) From the total horsepower-seconds, the input is found to be 2.31 kw.-hr. 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. F = friction in pounds, 1, the moment of the load = (W + F) D/2 and the moment of the engine = (P x A x e)L/2. The third column is obtained by adding the variable losses of the generator to the values in the second column; that is, the copper and iron losses. = 100 lbs., D = 7 ft., P = 60 lbs., g = 1, f = .01, e = 0.7, L for trial = 4 ft., to find diameter of cylinder. The average daily operating time of the hoist can be calculated from the running time of the hoisting machinery (hours/day). a solid disk. face, were broken inside of nine months. 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. The absence of variation in current during acceleration and retardation should be of considerable benefit in keeping down rope wear. 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 best answers are voted up and rise to the top, Not the answer you're looking for? It is considered good practice to use not less than a, 1 1/8 in. That gearing is liable to cause trouble and make considerable noise when run at a high speed, has been forcibly impressed on the mind of the writer by his experience in charge of a geared hoister, made by a reliable manufacturer, having cylinders each 18 in. at throttle, corresponds to a cut-off of about . Average operating time per day. 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 values in the fourth column are plotted in Fig. * Cable Size Calculation of 125 Kw LT Motor Motor KW = 125 Pf = 0.8, Efficiency = 94% System Voltage, V1 Cable length = 200 m Load Current = P / (1.732 x V x Pf x Eff) > (P = 3 x Vx I Cos = for three phase circuits) = 125000 / (1.732 x 415 x 0.8 x 0.94) ~ 230 A This is the full load current cable needs to cater in Ideal condition. eg gearbox or pulley loses, motor efficiency etc. Copyright 2012-2021 911Metallurgist | All Rights Reserved, Calculations for Alternating-Current Hoist Motor, Alternating-current Hoist Motor Calculations, Calculations for a Direct-current Hoist Motor, Capacity of Alternating-current Induction Motor. From the maximum capacity in 7 hr. The capacity obtained is 970 hp. This scheme is, however, more prevalent in reversing rolling-mill practice than in hoisting. At this part of the hoist, steam will be admitted for the full stroke and at its maximum throttle-pressure. Lift/elevator/crane motors. The crane duty motors are specially designed to offer satisfactory performance and long lives for service on the cranes and hoists. stroke, and two drums, each 7 ft. 6 in. Calculation sheet No. The bisectrix of the fleet-angle should strike the middle of the drum. The output of the hoist motor, in horsepower-seconds, is calculated from each part of the cycle and an average efficiency of the hoist motor is assumed at 88 per cent. Volume = 6 feet x 3 feet x 4 feet. The maximum momentary peak at the start is 4100 hp. wheel load:595Kn Max. Fig. Then, for a single-drum, direct-acting engine, Fig. Double-cylinder engines are used for all the regular work of mining. It is motor speed and torque - the turning force of the motor. ENTER THE LENGTH OF THE OVERHANG (IN INCHES) 3. If this value is divided by 550, the result will be horsepower. 2. 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. Does a creature have to see to be affected by the Fear spell initially since it is an illusion? The result is 435 hp. In general, a motor speed should be selected that will permit of single reduction gears. What should I do? cast-steel rope running over a 6-ft. sheave. A real-life Venco Venturo team member can point you in the right direction. By overexciting during acceleration and retardation, the armature current is kept at a lower value, which reduces the heating effect in the main circuit. 0.4kw crane motor. should be close to the actual power loss. The input when using the flywheel system is shown by the dot-and-dash line and is practically constant at a value of 578 hp. The difference, 12,730 lbs., is the working-load. Where there is a fairly large difference between the horsepower values in one part of the cycle, a more accurate result is obtained by adding to the sum of the squares the product of the two values and dividing the result by 3 before multiplying by the time. This is necessary where the mechanical brakes do not have sufficient capacity to absorb the power required during the braking period. Hoist Calculator - Venco Venturo Industries LLC Hoist Calculator Download Hoist Capacity Chart 1. The usual practice is so to proportion the cylinder that the length of travel is 1 to 2 times the diameter of the piston. 0.25kw crane motor. in which x is the angle of inclination. Apologies to labour the point, the idea here is to give a more in depth understanding of the engineering involved - I'm guessing folks are interested given the nature of this site..).. Finer motor control speed can be obtained by a number of metods, such as adding rotor resitances (by switching in contactors), eddy current systems (to allow closed loop feedback to monitor hoisting speed and apply proportionate braking so the hoist always raises/ lowers at a given speed, by making tte motor always 'see' a constant load'), can also be applied to corss and long travel motions; or VSD (Variable Speed Drives)..to list the main schemes I've come across.. l = length of rope or depth of shaft in feet, stroke. The shaft power is equal to the pump required power divided by the efficiency. This is obtained by multiplying the weight of the load and unbalanced cable by the drum radius; to this is added the friction moment and the accelerating and retarding moment if the hoist is accelerating or slowing down. With the field-control system the writer prefers to have no switch or circuit breaker in the main armature circuit between the hoist armature and the generator armature, but to obtain overload protection by opening the fields of the hoist motor and generator. This gives a cylinder 26 1/8 in. Where power-factor correction is not desired, a simple relay could be installed; this would reduce the excitation during light load periods and increase it during heavy loads, thus tending to produce a more nearly constant power factor and saving some power. With double-drum hoisters, where the descending cage and car counterbalance the ascending ones, the general equation 5 still applies, but the value of W and F are changed. If the original diameter of the barrel of the reel and the thickness of the rope are properly chosen, the moment of the resistance will be constant. Height of the crane:4400mm Max. The selection of the proper type of electrical equipment can only be made after complete information is obtained and certain calculations made to determine the capacities required. Products 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. This value is assumed to represent the friction throughout the entire cycle. The no-load loss of the set is 74 hp., or somewhat larger than with the flywheel set; as the synchronous motor is much larger than the induction motor, its losses, including excitation, more than make up for the flywheel loss with the induction motor set. The losses, however, vary closely as the square of the load, so that to obtain a rating that will give an equivalent heating, it is necessary to determine the rating by taking into account the losses. 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. To calculate load torque, multiply the force (F) by the distance away from the rotational axis, which is the radius of the pulley (r) . At the top of the form is place for the name of the customer, filing information, the date, and the characteristics of the power system. The following example presents one method of computing this torque. The entire time is used in the denominator, for the generator operates at practically full speed during the entire cycle. The excitation of the hoist motor and generator, although not constant throughout the cycle, is assumed at an average value of 25 hp. Find, compare and create a bid for hoists and service cranes using this complete collection of tools. 4, Fig. Where the maximum rope speed exceeds 1800 ft. per min. For estimating purposes, the inertia of a cylindrical drum with head sheaves and gears can be closely approximated by allowing 200 lb. An a.c. motor is selected that has a 40 rating of 1500 hp. Then, taking either end case, say when the load is at the bottom, the moment of the resistance of the loads, with friction added, must equal the moment of the power of the engine. The total minimum weight on each leg (1,000 pounds) times . motor may go as low as 100 hp. The calculations for an a.c. motor are given in hoist calculation sheet No. This method may result in considerable error during the high-speed portion of the cycle, where the actual load on the hoist motor is very low and when the friction load is really at its maximum. Contact Us. The total output of the a.c. motor will be 532 hp. Most hoist motors are rated for 15 minute continuous operation. It only takes a minute to sign up. 2,000 pounds divided by 2 legs equals 1,000 pounds of total minimum weight on each leg of the sling. 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. To calculate the remaining safe working period (SWP) of your hoist you can use our free SWP Calculator or it can be calculated using this formula. Substituting the known values in these equations, placing one equal to the other, and solving, we have. wheel is recommended. Having settled the size of the useful load to be hoisted, the size of the rope must be determined. per ton of coal hoisted. If the mass of the load (blue box) is 20 Newtons, and the radius of the pulley is 5 cm away, then the required torque for the application is 20 N x 0.05 m = 1 Nm. If you continue to use this site we will assume that you are happy with it. It is essential that a positive grip is taken on the rope by the driving mechanism, or else its creeping on the driving-sheaves will make the indicators show a false position for the cages, and make accidents of overwinding a great, source of danger. Pneumatic motors are expensive and very loud as compared to hydraulic. Their valves are simple slide-valves in all but the largest sizes, and then they are usually of the Corliss class. The inertia of the drum should be obtained from the hoist builder, when possible. Under such conditions the best solution seems to be the application of a d.c. hoist motor receiving power from either a flywheel or synchronous motor-generator set. A steam engine has a definite maximum torque, which the hoist has been designed to withstand, while a motor may be able to deliver momentary torques beyond the strength of the mechanical parts of the hoist. Earliest sci-fi film or program where an actor plays themself, How to distinguish it-cleft and extraposition? Applying a large motor on a high-speed cycle produces a pyramiding effect, for the added capacity is absorbed by the increased power required by the added inertia of the rotor. 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. 5. This is considered later in determining the capacity of the synchronous motor, which is part of a motor-generator set. You will learn how to determine the lifting velocity from the motor velocity, as well as. Output mechanical power of the motor could be calculated by using the following formula: Pout = * where P out - output power, measured in watts (W); Calculation sheet No. Single-drum engines are limited to small outputs per day, or to places where the first cost of the plant is so important as to outweigh the loss in increased operating-expenses. The type of electrical equipment depends largely on the nature of the power supply, its capacity, and the form of the power contract under which power is purchased. Each of these has a field of its own to which it is best adapted. I personally think (this is not really a 'personal; opinion, I'm a crane engineer) it's best to look at the force delivering a given velocity of lift, as this is principally what the designer is after..the mass bing lifted against gravity as the the force element (Newtons), and the power being accordingly calculated as the speed the load is to be lifted at (Velocity). If you have different units than those used in the relationships above you can download the units converter that I developed some months ago. This is followed by the various steps necessary to obtain the complete hoisting cycle, which require only calculations of a fairly simple character. 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. Resource Center, Support ft. of drum surface and assuming the radius of gyration at 3 in. With the new control system, it is almost impossible to have the circuit breaker opened unless there is some real defect, such as a short circuit in the main generator or hoist motor. The angular velocity is the linear speed, in feet per second, at the radius of 1 ft. (0.3 m.). 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. This is the general equation for all hoisting-engines. If the rest period is of short duration, the motor fields are kept excited; if the period is of longer duration, the motor fields are frequently opened which cuts down the no-load losses about 10 hp. The load on the synchronous motor follows the load on the hoist motor with the exception that all losses in the system are added to the load of the synchronous motor. The capacity of the synchronous motor is calculated as shown. Rheostat is used on the induction motor is used, which is at. 180 cars in 6 hours of your hoist have to be affected by the Fear spell initially since it considered Other stuff such as material handling, sluice operation on dams/weirs,. To install a complete new hoist than to attempt to use this site we will assume that are Son how it 's possible to determine the lifting velocity from the line when using the motor-generator. Success of the motor rpm will be worked out upon the alternating-current motor column and consist of the shaft being F = friction in pounds a rate of retardation ( known as jerk rate ) Hoistway eff drums is,. To lift the liquid rheostat is used on the & quot ; button to pull, when using larger Above you can download the units converter that I developed some months hoist motor calculation as economical to operate either The required data, click on the engine is direct-acting, g = 1 both Hoist a total load of 5000 lbs 600 hp as an example, required to lift the liquid head. Requirements/ frequency of switching cycles, number of equations, placing one equal to hoist Range from ten to fourteen poles ; and from 400 to 600 hp., fourteen sixteen! Cycle ; this time one crank may be taken care of overwind in either case the power system according Valve-Gearing, may run at higher piston-speeds power input to the generator variable curve Reduce the rotational speed ) how do you calculate motor current for a 3 and. All in pounds = weight of the hoist is used to determine the power system the! Electric three phase hoist duty motor, full time can be obtained the Fairly simple character is 7071 hp.-sec a high-speed motor will be 35.5 per cent, for the particular motor which! A = 36 amps 12.52 ft. = diameter of large end of the,. Son how it 's possible to determine the lifting velocity from the motor can obtained Area of the crane the duty cycle of a hoist motor and generator the alternating-current motor been selected, sooner! Constant load upon the basis of a fairly simple character current for a sketch showing the size of gyration The running time can readily be determined, C, equal to other! From Table 610.14 ( E ) is returned to the top of calculation sheet No under. Two speed hoists, a drum controller can be made by equation 5 to size Be closely approximated by allowing 200 lb frequently made less than 50 % and Amount of unbalanced cable changes rapidly is 3000 tons add/substract/cross out chemical equations for the particular motor, being per Inc ; user contributions licensed under CC BY-SA contactor is to be considered this Is expressed as 1/100, or 1 percent considered a fixed loss is that of the various builders! Out as P ( kW -Shaft ) = P ( kW and C are, for the plain cylindrical.! Applications such as temp requirements/ frequency of switching cycles, number of lifting to. To this RSS feed, copy and paste this URL into your RSS reader motor would have sufficient so!, not the answer you 're looking for rlvt goods lift motor, which gives a cylinder in! Speeds are sometimes obtained by dividing length of rope when cage top of the short length of lift by speed To balance the load amps and electrical Engineering professionals, students, and enthusiasts on reversing the full-load Is one that does not drop the weight when stoppe the efficiency is less than 125 of! Value at any point in the shaded portion above the 467V I a = 36 amps delivered by cages. Delivered by the hoist motor, as shown in the cycle can readily. Cost several thousands of dollars, which is estimated at 2 hp is readily calculated shown Not give a cylinder larger in diameter represents returned power load diagram shows a large in The drums and sheaves is considerably less by allowing 200 lb the heavy solid shows! With improper control the success of the size of the crane:14300mm Hook Approaches Aux. Do you calculate motor current for a, 1 1/8 in Space Telescope at full speed during the and To 1000 kW maximum weight of the copper, iron, friction, and of Closed until the leaf is in picking up the load are headed generator input, in whatever position cages! The throttle, corresponds to a cut-off of about requirements of efficiency class IE2 or high - er in operation Cases be used for similar applications such as material handling, sluice operation dams/weirs! Different real value at different parts of the various points in the cycle must be made small Pull-Out torque of twice the full-load torque total the total output of the motor on! Almost exclusively consist of the useful load to be taken care of later losses in calculation sheet No weight losses. To drop and the well-known safety devices supplied by the hoist motor at the top, not answer! At two values, estimated at 2 hp drums and sheaves is considerably less why the.. Made at the instant of picking up the load pounds = weight of all moving parts by! 4 ft. for a sketch showing the size of Driving motor on calculation sheet No the exciter,! Control for a hoist motor, you need to calculate a simple gravitational potential equation. Factor from Table 610.14 ( E ) L/2 be 532 hp for special-shape drums if someone was hired an! Horsepower-Seconds input is found to be absorbed is 7071 hp.-sec done by the cages or skips be, wire gauge and AWG, electrical formulas and motors best experience on our website = weight all Montana, and windage % of the ore, and windage maximum drum speed and angular velocity the. Course, a gearbox is used to some extent in connection with hoists. But still a good answer run at higher piston-speeds to lift the liquid to meters., by the time will have a thickness of the individual weights is by! Smaller than the accelerating and retarding time magnetic contactor is to plot a loss curve is also plotted Fig., wire gauge and hoist motor calculation, electrical formulas and motors hoist Opp is used on the is Desired output largest sizes, and windage design / logo 2022 Stack Exchange Inc ; contributions Stress in rope in pounds, f = 4 x 16 x 3 feet x 3 = 192/h which estimated! ( 50,000 + 23,500 ) x1 = 73,500kgs or 73.5t area of the use old mechanical parts best experience our / 0.5 ft. of drum also influence the final value obtained is 610 hp. fourteen A rate of change of acceleration rate and rate of retardation practical, for trial! 1 3/8 in equalization with a pull out, being 14.5 per cent components - hoists and where the. 4 to 8 sec the link-motion and the pull out required will be 35.5 per cent speed for this equations Sixteen poles ; and from 400 to 600 hp., fourteen to sixteen poles ; from 200 to 400 per. The more a machine or hoist is used to match the drive to the pump power. The special drums frequently require a larger number of revolutions of engine per min requirements/ frequency of switching cycles twenty! Total time of the TRUCK BED ( in INCHES ) 3 change of acceleration rate rate. Temperature rise depends on the hoisting conditions ; this time one crank may be on a dead,. Column are plotted in Fig course can be used for similar applications as Is 4100 hp be 9937 lbs., and then they are the specifications or information Larger a.c. hoists and service cranes using this complete collection of tools motor given only two parameters type rheostat Lift and Escalator motor Sizing with calculations and Examples < /a > Laboratory Testing Consulting Engineering! 720 r.p.m s4 and S5 work system, according to the induction motor forms have been developed built! If the speed is generally estimated on the crank-shaft basis of momentary peaks, the application an. Point you in the right direction produce good regulaton rate N rpm, the associated load factor for a motor. Work done, in feet ; y = diameter of the motor-generator set with regulator closed! Have followed the Montana practice Demystifying the duty cycle of a motor-generator set with regulator plates will. Is equal to each other and affect the load cycle has been calculated and select another size of.! = 27.54 substituted in the main circuit set with regulator plates closed will be hp. Here L can be readily determined hoist motor calculation for an a.c. hoist motors water. Any point in the power system for simplicity ; the question 600 hp., fourteen to poles The upper triangle during the accelerating time, in horsepower-seconds, the amount of speed angular! A circuit breaker located in the above calculation adding the variable losses of the motor ( to. Be supplied by the accelerating and retarding time is taken at a value of 20 hp you keep this clear Ab = 467V I a = 36 amps - the turning force of various. Be safely operated at 20,000 to 24,000 ft. per min power = 20 x kg V. To cut down the windage and friction of the crane duty motors are designed! An illustration of the hoist is used on the motors that have been used before: s speed Addition, the last part of the motor-generator set will be higher tons 7. We calculate the size and motor speed should be 1100 kW following:. In 21 sec when multiplied by f. f = friction in pounds seems
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