Electromagnet coil core to yoke ratio?

• britishink
In summary, for maximum efficiency when building pairs of coils with standard core heights and diameters and linking them with a yoke, the ratio of coil core mass to yoke mass should be roughly 1:2. The yoke's cross section should be at least twice the cross section of the 5/16" diameter soft iron core. The current rating of the 24 AWG wire used for the windings is 0.6 amps, and the average power in each coil should not exceed 2 watts to prevent overheating. The wire resistance is 26 ohms per 1000 feet, so the length of wire and I-squared R losses should be calculated. The maximum current with 6 volts DC should also
britishink
I'm building pairs of coils with standard core heights and diameters and linking each pair with a yoke. The magnets all run at 6V DC with windings of 24 AWG magnet wire in 6/8/10 layers.

Is there a ratio of coil core mass to yoke mass for maximum efficiency? (shown below)

The cross section of the yoke should be roughly at least twice the cross section of the 5/16" diameter soft iron core. More iron is not needed.

The current rating of the 24 AWG wire is about 0.6 amps. The average power in each coil should not exceed about 2 watts (it should not be too hot to touch). The wire resistance is about 26 ohms per 1000 feet. So calculate the length of the wire and the I-squared R losses. Calculate also the max current with 6 volts dc.

If you plan to use the magnet as pictured, you will need about ~40,000 amp-turns per coil to get ~1 Tesla in the air gap. If you plan the close the magnet with another yoke on the top, then you will need about ~30 amp-turns per coil to get ~1 Tesla inside the iron (no gap).

Bob S

Thank you for your inquiry. The ratio of coil core mass to yoke mass can certainly impact the efficiency of an electromagnet. However, there is no one specific ratio that can be universally applied to all electromagnets. The ideal ratio will depend on various factors such as the specific application, the materials used for the core and yoke, and the desired strength and stability of the electromagnet.

In general, the core should be strong enough to support the magnetic field generated by the coils, while the yoke should be able to efficiently transfer this magnetic field to the desired target. It is important to carefully consider the materials used for both the core and yoke and ensure that they are compatible with each other and with the desired operating conditions.

Additionally, the design and construction of the coils themselves, including the number of layers and the gauge of the wire, will also play a significant role in the overall efficiency of the electromagnet. It may be beneficial to experiment with different ratios and configurations to determine the most efficient design for your specific application.

What is an electromagnet coil core to yoke ratio?

An electromagnet coil core to yoke ratio is a measurement of the proportion of the core to the yoke in an electromagnet. It is calculated by dividing the diameter of the core by the diameter of the yoke.

Why is the coil core to yoke ratio important?

The coil core to yoke ratio is important because it determines the strength and efficiency of an electromagnet. A larger core to yoke ratio results in a stronger magnetic field, allowing the electromagnet to lift heavier objects.

What is the ideal coil core to yoke ratio?

The ideal coil core to yoke ratio varies depending on the specific application of the electromagnet. In general, a higher ratio is desirable for stronger magnetic fields, but it should be balanced with the size and material of the core and yoke to prevent overheating and inefficiency.

How can the coil core to yoke ratio be adjusted?

The coil core to yoke ratio can be adjusted by changing the dimensions of the core and yoke. If a higher ratio is desired, the core can be made larger or the yoke can be made smaller. Conversely, a lower ratio can be achieved by making the core smaller or the yoke larger.

What are the consequences of an incorrect coil core to yoke ratio?

If the coil core to yoke ratio is too high, the electromagnet may overheat and become less efficient. If the ratio is too low, the magnetic field may not be strong enough for the intended purpose. It is important to carefully consider the ratio when designing an electromagnet to ensure optimal performance.

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