# Tag Info

25

A motor with 1 kg.cm torque is capable of holding a 1 kg weight at a radial distance of 1 cm. Here is a diagram to explain. Torque is the cross-product of force and distance: $\tau = F \times d$. So the same weight, at twice the radial distance, will require double the torque. Note that the measurement 'kgcm' is 'kilograms-force × centimetres' and ...

13

After 4 years using and studying electrical vehicles I figured out that "gradeability" (ability to raise a slope of specific grade) depends on motor torque, and torque depends on current. Voltage instead "regulates" how fast a motor can run: the maximum speed a motor can reach is the speed at which the motor generates a voltage (named "Counter-...

11

Conceptually, you have to think about this slightly differently. The way I think you are thinking about this is kind of like torque in a vehicle. A car with more torque is going to accelerate more quickly and is associated with an increase in speed. In other words, you press on the gas pedal to increase the speed and you need torque to do that. However,...

11

Fix a lever of a precise known length to the specimen and add calibrated masses. Measure the deflection with a dial gauge. Perpendicularity might be a concern and could be addressed with geometry... However, the error that introduces is probably small compared to other sources. The sources of errors may well be worth checking. I know that for the ...

10

When the armature of a dc motor rotates , we call it torque because of rotational movement about the fixed axis. So where is speed? We don't call it torque, we call it speed aka rpm or rotational speed. The force that it takes to spin at a certain speed we call torque and usually, for a dc motor high speed means low torque and high torque means low speed....

10

The data is all given on the page you linked. The relevant quantity is the "Stall Torque", which is the maximum torque the motor is able to exert. Note - as the warning text, below the table, says, you should not plan to operate at this stall torque for more than a few seconds at a time. To convert stall torque to "a weight", take the stall torque in ounce-...

9

Torque is how hard you push, and speed is how fast it goes. In a electric motor, torque is proportional to current, regardless of the applied voltage. Think of a motor as the coils that cause the torque in series with a voltage source. The coils are always the same, and the torque produced by the magnetic interactions inside the motor are always ...

7

Since the table already has a crank, it's pretty easy: just use a spring scale to measure the force on the crank as you pull it through a complete cycle. Be careful to keep the axis of the scale at right angles to the crank arm at all times, and record the highest value you see. The torque is the value on the scale, multiplied by the length of the arm.

7

The short answer: they were both designed to do what they needed to do. One just cost more to do it. The long answer: Horsepower is proportional to speed. If you could spin that industrial motor as fast as the Tesla motor could spin, it might get close to the same horsepower - just before it shatters into a thousand flying pieces. The industrial motor was ...

7

The motor controller acts as a buck type switching regulator with the motor windings acting as the inductor. Since the voltage across the windings when stalled is only the resistive drop from the current passing through them, there's no back EMF to overcome from mechanical work being done, the controller will be switching at a (fairly low) duty cycle that ...

7

The Visible bit of bright copper is part of a shading ring .Your motor is single phase and relies on the shading rings for starting torque .When you strip the motor check the integrity of all the shading rings because you want rated torque .Also check the bearings ,they must be really free to turn .Starting torque of these types of motors is useless but they ...

6

In any motor, the basic principle is very simple: rotational speed is proportional to voltage applied torque is proportional to current pulled A 100 volt motor is a motor that can take a maximum of 100 volts, and a 50 volt motor a maximum of 50 volts. Since the 100 volt motor can take more volts, if all else is equal, it can give you a higher maximum ...

6

Note that your question states that you want to reduce the starting torque, but you actually want to reduce the starting current. There are a few ways to reduce the starting current of a three-phase induction motor. In rough order of cost: Reduced Voltage starters These methods apply a reduced voltage (say 50%) to the motor on first starting. This reduces ...

6

It depends most on what and how you are fastening. Many different materials will have different properties. For example, the compressive strength of FR4 material is at least 460MPa, or 460N/mm^2. That number is one you want to stay well clear of, especially if you have multi-layer boards (since you don't know the exact specs of the prepreg your fab uses). ...

6

The braking options are mechanical, dissipation, and energy recovery. However when the vehicle is at a stop, braking can only be via mechanical static friction or via electrical dissipation generating static counter-torque. Current in the windings is highest when the motor is not turning, because there are motoring coils and generating coils. When shaft ...

5

Of course having the generator produce electrical power puts a load (torque in opposition to rotation) on the shaft. Without such load, there would be no mechanical power transferred into the generator, and it would violate conservation of energy by producing electrical power. Electric generators, which can be thought of as mechanical to electrical power ...

5

You seem to be confused about what you want. If you want to decrease the motor speed, but you still want maximum torque, then you must apply full rated electrical power to the motor, and put a mechanical brake on the motor until it slows to the speed you desire. Or, you must somehow make your motor less efficient. I don't think that's what you want. Think ...

5

Calculate separately the powers you need for acceleration (simple Newtonian physics) hill climbing (ditto, once you decide what speed you want up what gradient), rolling resistance (you'll need to research that, for the ground surfaces you're crossing. It depends on speed, ground surface, type of tyre, wheel size etc, you'll find plenty of info online to ...

5

I think you don't fully understand the specs of the motor. Stall Torque = 20 Kg/cm The unit is Kg*cm. And when a wheel of 4" diameter, i.e. 2"=5cm radius is directly mounted to the shaft, the "force" is 20Kg*cm / 5cm = 4kg. This means: If you put a string around the wheel and use it as winch, it could lift a weight of almost 4kg (8.8lbs) before it stalls....

5

In a permanent magnet or shunt-wound DC motor torque is directly proportional to current, and the torque constant (Kt) is the inverse of the velocity constant (Kv). If your motor does 12000rpm at 12V unloaded, then (assuming no-load current is 'small') Kv = 1000rpm/V or 105rad/s/V. The inverse of that is 1/105 = 0.0095N-m/A or 97g-cm/A. At 1.2A it would ...

5

What do I have to search for? "Gearmotor" or "gear motor" are the most likely search terms. Products like the one pictured are made in huge quantities and are made with gear motors that are likely either designed and built by the product manufacturer or designed and manufactured under contract with them by another company. There are relatively few gear ...

5

I like your thinking on this. You see something about it that bugs you so you ask a question. Those little things that bug you because they don't fit, and the curiosity to pursue them are very positive traits in engineering and science. But I think you are mixing up a few different motor types. Induction motors are the ones that have slip. If you run an ...

4

simulate this circuit – Schematic created using CircuitLab This is a steady-state approximation of a dc motor that works fairly well with some types of dc motors(see comment by supercat). Since steady-state, the armature inductance $L_a$ is neglected. We have the following: \begin{align} V &= \text{input dc voltage}\\ R_a &= \text{...

4

Assuming you are referring to the motor slowing when you increase the field current (in a motor with a separate field winding, rather than a permanent magnet motor: Remember what controls the speed of a lightly loaded motor : the speed increases until the back-EMF approximately equals the driving voltage. The back-EMF is generated by the motor acting as a ...

4

Relating a motor's current to a fan output airflow requires you to know details about the motor, the fan, the mechanical system surrounding the fan, and the ambient atmosphere. The motor current depends on the motor speed, as shown by a speed vs. current curve. The motor speed depends on the motor's speed-torque curve vs. the fan's speed-torque curve. The ...

4

I use a TackLife 1-4 Nm adjustable electric torque screwdriver. 1 Nm is too much torque for standard PCB material to handle before cracking if your screws don't strip. I'm assuming most PCB material is similar in composition. 0.6 Nm torque adjuster is required at work when assembling PCB components, 1 Nm for body/frame connections (metal on metal). Our ...

4

A rectangular 9v "transistor radio" battery is entirely unsuitable for powering motors. Not only would it run down in no time and be expensive for the amount of energy provided, it has such a high internal impedance that the voltage would sag beyond the point of effectiveness when connected to the low impedance load of a motor. For the motors you have, you ...

4

During half of a cycle of the power frequency, the position of a rotor pole moves from one stator pole to the opposite pole of the same pair. If the motor has only two poles, that rotor pole moves back to the original position during the next half cycle. So there is one revolution per cycle of the power frequency. If there are more than two poles, the rotor ...

4

V = IR To the first order, stall current = Applied drive voltage divided by the DC resistance of the coil. The stall current occurs when the motor is stalled (not moving), so there is no reactance and no "back electromotive force (EMF)". It's literally only the resistance of the wiring in the servo motor that is resisting the flow of current... just like a ...

4

Keep it simple. To measure the torque simply create a transversal arm attached to the motor using a known length. Let the whole motor free to turn (not the shaft, the outside case) along with the attached arm. The arm tip, opposed to where it's attached to the motor, can then be placed on a balance. You can measure the torque now using the balance measure ...

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