How does an eddy current speedometer work?
How mechanical (eddy-current) speedometers work. As the speedometer cable rotates, it turns the magnet at the same speed. The spinning magnet creates a fluctuating magnetic field inside the speed cup and, by the laws of electromagnetism, that means electric currents flow inside the cup as well.
Do you know the answer to the speedometer?
If you were staring straight ahead, not looking at the dashboard, you might have only a vague idea what to say. If you were looking at the speedometer, on the other hand, you’ll know the answer exactly, possibly to within one or two kilometers or miles per hour. Have you ever stopped to think how a speedometer actually works?
How does the magnet in a speedometer work?
The magnet rotates inside a hollow metal cup, known as the speed cup, which is also free to rotate, though restrained by a fine coil of wire known as a hairspring. However, the magnet and the speed cup are not connected together: they’re separated by air.
When did Otto Schulze invent the speedometer?
Even that problem isn’t simple. Imagine how much harder it must have seemed in the early days of motoring, back in 1902, when German engineer Otto Schulze invented the first practical solution: the eddy-current speedometer. Here’s what we want out of our speedometer.
Is it possible to make your Speedo and odometer inaccurate?
You just made your speedo and odometer inaccurate. Here’s how to fix them both. If you’ve ever modified a car with smaller or larger tires or, perhaps, a different final-drive gear, you’ve immediately screwed up your speedometer. This is, of course, annoying, but for modern cars with a digital speed sensor, there’s a relatively easy way to fix it.
How do you check the odometer on a speedometer?
B—Check the odometer reading, in miles and tenths of a mile, as you pass a mile marker and then check it again as you pass the next mile marker. C—Check it again two more times to be sure that your reading is accurate. A—Unscrew cable end at the speedometer head.
Why is my speedometer not working on my new car?
If you’ve ever modified a car with smaller or larger tires or, perhaps, a different final-drive gear, you’ve immediately screwed up your speedometer. This is, of course, annoying, but for modern cars with a digital speed sensor, there’s a relatively easy way to fix it.
Where can I find a mile marker for a speedometer?
A—Find a measured mile. Use the mile markers on an interstate highway or a speedometer test zone. Interstate highways have markers for each mile and some state or county roads have markers that can be used if you pay close attention to the tenth-of a-mile markers.