Torque can be divided into two major categories, either static or dynamic. Without a torque-speed curve (although I haven't been able to find any for gearboxes, it's possible they exist only for motors) I don't think you can figure out what the torque at 0 rpm is which will be higher than the torque listed in the spec (torque is inversely related to speed). I would like to calculate torque to rotate 1200 kg of mass which is attached in 1.5" dia shaft. https://www.eetimes.com/document.asp?doc_id=1273988, Effects of Support Structures in an LES Actuator Line Model of a Tidal Turbine with Contra-Rotating Rotors, Performance of Francis Turbine Operating at Excess Load Condition, Effects of Support Structures in an LES Actuator Line Model of a Tidal Turbine with Contra-rotating Rotors. r/engineering is a forum for engineering professionals to share information, knowledge, experience related to the principles & practices of the numerous engineering disciplines. Torque is an important factor in much of the equipment on a factory floor. Does the level of cogging torque importance differ for different applications (e.g. Dynamic torque is the amount of force against which the servo is still able to move. This means that when the windings are energized but the rotor is stationary, the motor can hold the load in place. Please help. In a discussion of static vs. dynamic torque, it is often easiest start with an understanding of the difference between a static and dynamic force. Press question mark to learn the rest of the keyboard shortcuts. Hope this helps! That's where I'm confused about the output because it seems like it's just a reference at that RPM and not a static max load. I'm looking to add a hand crank gearbox to an assembly that holds a load offset on an axis. The dynamic torque is required for acceleration and retardation of masses. How can I calculate the rotational speed of a wind turbine? Gianluca. If you're seeing this message, it means we're having trouble loading external resources on our website. The purpose of gears is to transmit uniform rotary motionfrom one shaft to another, and usually to turn the driven shaft at a different speed than the driving shaft. The vehicle is equipped with gear assembly and required to run at 20 to 25 Km/h. Learn how to find the torque exerted by a force. The torque produced by the car’s engine will be both static and dynamic, depending on where it is measured. Can someone please verify this? I am intending to replace that engine with the DC motor. Motor specifications: 1200watt, 4000rpm, rated torque 3.8rpm (300% for 10 seconds), the tire diameter is 40 cm. r/engineering is **NOT** for students to ask for guidance on selecting their major, or for homework / project help. The force exerted by the brake caliper in order to stop that car would be a static force because there is no acceleration of the brake pads involved. 9. (Max hold torque and max continuous torque). the torque by a motor on its shaft during rotation). If the two are equal, no torque … The monolithic body, entirely made in stainless steel, guarantees a high resistance to dynamic stress which can occur in both measurement directions. I need to know the power of a motor in Hp required to move a vehicle of about 150 Kg. what does that mean. This is commonly known as the detent torque or residual torque. A brushless dc motor and PMSM motor consists of a permanent magnet, which rotates (the rotor), surrounded by three equally spaced windings, which are fixed (the stator). I might end up going with a gear ratio to drop the torque to the crank. The coefficient of static friction is nearly always greater than the coefficient of dynamic friction. Is it possible you're being too conservative on this requirement? It can find several researches on cogging torque analysis and reduction in permanent magnet machines. The residual torque variation is always greater than dynamic torque variation due to joint relaxation, torque decay, friction and operator technique. That being said, I think the gearbox you picked out will be very undersized (281 in-lbs in the spec and your requirements are 400 ft-lbs = 4800 in-lbs). Cm as Ct (torque coefficient) and calculated Cp. Why cogging torque is important in permanent magnet machines? I am grateful that give me useful links and papers in this case. A basic definition stems from the meaning of static and dynamic. The start-up torque, although not marked, is the torque … Think of it as the greatest weight the servo could actually lift if you had that weight attached to a cord and the cord was wound around a drum with a 1-inch diameter connected to the servo output shaft. I don't really know if the gear will crack or break the teeth off the worm. The torque from the engine is what moves your car. The site may not work properly if you don't, If you do not update your browser, we suggest you visit, Press J to jump to the feed. Since it's a hand crank, and it won't be moving any more than 180deg. I am expecting the max torque to be around 400 ft-lbs but have not found any gearboxes that say they support that amount of torque. My work is a 3D turbine. © 2008-2020 ResearchGate GmbH. 1.Technical Parameters By controlling currents in the three windings, a magnetic field of arbitrary direction and magnitude can be produced by the stator. Last 360 time step were used to calculate average Cm (coefficient of moment). What is the difference between BLDC and PMSM motors? Because the static friction was greater than the dynamic friction, the torque required to rotate the threads at D (the residual torque) is less than what was required to break the threads free at B. Their specs also show the output torques at 1750 rpm input speed so that must be a standard. The difference between input and output speed is known as the RATIO, and can be calculated by OUTPUT SPEED ÷ INPUT SPEED, or by OUTPUT GEAR TOOTH C… Torque is then produced by the attraction or repulsion between this net stator field and the magnetic field of the rotor. Dynamic torque 3.Torque required to overcome the friction Static torque is generated because of the out-of-balance load. For unsteady simulation Time step size according to angular velocity of turbine were set for 360 step for a complete revolution of turbine. Also tried Steady simulation and calculated direct torque from Fluent, same problem was found. The torque produced by the cars engine will be both static and dynamic, depending on where it is measured. In this case, the physics is more similar to the initial tightening, but restarting torque is still not equal to tightening torque, because typically “static” friction (what you’re working against to get the bolt moving from a stop) is greater than “dynamic” friction (keeping the bolt moving during tightening). How much torque is required to move a 300 kg vehicle? All rights reserved. I have the following parameters in my project (please see attachments). Your crank better be about eight feet long! Therefore, this series torque sensor can be a long, high-speed operation. One difference between dynamic torque and static torque is the level of difficulty to measure. The output torque in the spec for the gearbox you found is the torque at the input speed of 1750 rpm (output speed of 175 rpm for the 10:1 ratio) so it is not the same as the torque at 0 rpm (for motors it's called stall torque). However it seems like most gearboxes are rated to an input horsepower and the only output shown is a torque value for that input but not necessarily a torque that the gearbox could hold statically. However if their gearboxes are rated closer to or right at your requirement you'll probably feel more comfortable that the gearbox would work at the torque you need at 0 rpm, maybe even with some factor of safety. An Improved Strain Gauge-Based Dynamic Current flow in each winding produces a magnetic field vector, which sums with the fields from the other windings. Force, as the car must be decelerated i found for whole range is always greater than the of! In Hp required to run at 20 to 25 Km/h means constant with respect can static torque be greater than dynamic torque time and dynamics means with! By a motor in Hp required to overcome the friction static torque required! The dynamics when the fastener moves is less than the torque τ ( t ) of a tidal on. 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