What is Dynamometer: Definition and 20 Discussions

A dynamometer or "dyno" for short, is a device for simultaneously measuring the torque and rotational speed (RPM) of an engine, motor or other rotating prime mover so that its instantaneous power may be calculated, and usually displayed by the dynamometer itself as kW or bhp.
In addition to being used to determine the torque or power characteristics of a machine under test, dynamometers are employed in a number of other roles. In standard emissions testing cycles such as those defined by the United States Environmental Protection Agency, dynamometers are used to provide simulated road loading of either the engine (using an engine dynamometer) or full powertrain (using a chassis dynamometer). Beyond simple power and torque measurements, dynamometers can be used as part of a testbed for a variety of engine development activities, such as the calibration of engine management controllers, detailed investigations into combustion behavior, and tribology.

In the medical terminology, hand-held dynamometers are used for routine screening of grip and hand strength, and the initial and ongoing evaluation of patients with hand trauma or dysfunction. They are also used to measure grip strength in patients where compromise of the cervical nerve roots or peripheral nerves is suspected.
In the rehabilitation, kinesiology, and ergonomics realms, force dynamometers are used for measuring the back, grip, arm, and/or leg strength of athletes, patients, and workers to evaluate physical status, performance, and task demands. Typically the force applied to a lever or through a cable is measured and then converted to a moment of force by multiplying by the perpendicular distance from the force to the axis of the level.

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  1. L

    DIY Simple analog engine dynamometer -- How to do it?

    Hi, I have to measure the HP of a small engine at the crankshaft. The only usable things are. A dinamometer A brake disk An rpm meter The brake caliper is floating so when we apply de load it pull the dinamometer. The rpm meter show the revolution during the load apply. It can works? How I...
  2. E

    Calculate the mass when not hanging it in dynamometer

    Homework Statement Hello! I have a physics problem that I can't solve. I'm supposed to describe how I can calculate the mass when knowing the µv (I don't know the english term but I'm guessing friction...something (friction when the object is not moving)). You are allowed to use a dynamometer...
  3. marellasunny

    Automotive Calculating the angular acceleration of a swivel seat

    We have an automotive swivel seat that turns from the initial seating position to the final position outside the vehicle (90 degree swivel in 15 seconds). We would like to calculate the torque required for rotating the seat along with the person. We have calculated the inertia of the movable...
  4. Omkar Bhalerao

    Engine & Dynamometer Coupling

    Can I use a Clutch Plate assembly along with drive shaft to connect Engine & dynamometer? I am facing an issue where in CRDi engine, at a position of accelerator pedal RPM is increasing from 1300 to 2000 without any change in accelerator pedal position. And a lot of vibrations takes place at...
  5. T

    Single cylinder engine dynamometer

    i am working with a Honda Gx-35 engine (1.2kw and 1.9 N-m) for a project and wish to make a dynamometer to measure its torque and hp.Was wondering whether an electric motor or an alternator should suffice my needs? wont the voltage regulator in the alternator keep my o/p constant? please help
  6. P

    Weighing with A 400 N Scale and 80 N Spring Dynamometer

    Homework Statement A former student of mechanics wishes to weigh himself but has access only to a scale A with capacity limited to 400 N and a small 80 N spring dynamometer B. With the rig shown he discovers that when he exerts a pull on the rope so that B registers 76 N, the scale A reads 268...
  7. F

    How does an electric dynamometer measure friction power?

    So I read that in a motoring test (to test the engine power), the engine is run to the desired speed by its own power. The power is absorbed by an electric dynamometer. Then, the fuel supply is cut-off and the dynamometer is converted to work as a motor to drive the engine at the same speed...
  8. B

    Help with calculation for dynamometer build?

    I'm looking for someone who can help me calculate the torque there will be transferred to my couplings between the rollers and to my belt connecting the 2 set of rollers. I have drawings of it all including inventor pro 2011 drawings/file of it all putted together without the belt and couplings...
  9. H

    Determine Torque Data Without Dynamometer

    Hi, this is my first post here. I have come across this site many times when looking for help and have found the most helpful information here. Thanks! I am creating a spreadsheet that you can input your vehicles Cylinders, Piston Diameter, Stroke, Displacement, HP, Torque, Size, Weight, Tires...
  10. F

    What does the Dynamometer show?

    Homework Statement What does this dynamometer show? http://imageshack.us/photo/my-images/826/0uqz.png/ That's pretty much the entire problem, I realize that this is utterly pathetic to post here but I lack the very foundations in physics and after googling this "problem" I still...
  11. T

    I am wanting to create my own Dynamometer for my physics class. (Im a

    I am wanting to create my own Dynamometer for my physics class. (Im a student by the way.) I want to leave something behind. This teacher has really helped me get through this class and make it very enjoyable at the same time. And for the class we are suppose to make a project or test a...
  12. R

    Using a timing belt for a Dynamometer

    Hello, I was wondering if someone could help me understand this situation. I am designing a motor/generator dynamometer, which is to be arranged as shown in the attached picture. There is a fixed high power DC motor transmitting power via a Syncronous / Timing belt to a motor which is...
  13. L

    What is the weight of an object with a mass of 0.5kg on a dynamometer?

    Homework Statement I am trying to help my lil bro (12 yo) with some physics. I've never been good in physics and now it's been more then 10 years that I've been to elementary school. I've helped him with some stuff but there's this one question that i don't understand and there's very little...
  14. O

    Amsler Pendulum Dynamometer PM103

    Please help We have an old Amsler Pendulum Dynamometer type PM 103 tensile testing machine which has been working admirably for many years - recently we started having problems with slight variations in loading rate and a tendency for the pendulum to bounce when loading is applied/removed...
  15. V

    Build Your Own Homemade Dyno for Small Engines

    Hi guys. I'm interested in building a dyno to test modifications to small engines (lawnmower engines). I've found this old topic: https://www.physicsforums.com/showthread.php?t=117800 But I'm having some trouble picturing the design. I like the idea of using an electric motor and an...
  16. R

    Does alternator work as dynamometer?

    does alternator work as dynamometer?? i'm doing small engine test rig to analyze it performance characteristic. then,i connect the pulley to alternator.thing that i need to considered is power that can produced from alternator must be larger that small engine.from engine specification, it can...
  17. E

    Tachometer for Inertia Dynamometer.

    Hi, I'm currently involved in a project designing an inertia dynamometer. Were looking for a suitable tachometer that we can use to measure the rpm with, it should give a voltage output in the form of an analogue sinusidal signal. This is so we can interphase it with a p.c. Does anyone have...
  18. A

    How can I design a homemade dynamometer for small engines?

    hey all, as you may or may not know, I am playing around with some different engine designs for a project, and I am using small engines, under 5 HP, and I was wondering if anyone had a suggestion about how to get a reading so I could determine what gave me more power vs what could hurt...
  19. I

    Solving the Weight of a Meterstaff with a Dynamometer

    A meterstaff who weights 0,12 kg is moveable around of it's ends. In the other staff it hangs a weight of 0,50 kg. The staff is hold in a line by a dynamometer, who is fastened in the middle of the staff. What does the dynamometer show? I take 0,12*0,50*6,67*10^-11 =4,002*10^-12 / 1^2...
  20. K

    What force does the dynamometer display?

    Hi! Really simple question: Two people are pulling on the ends of a dynamometer, each with a force of 25N. What force does the dynamometer display? Textbook answer: 25N I'm having a difficult time understanding this conceptually. Could anybody explain why the answer is 25N? Thanks...