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| Power Supply: Build or Buy? |
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| tautech:
--- Quote from: br4n_d0n on May 10, 2023, 03:36:22 am ---No one has touched on the electromagnet part; it will probably be dependent on its specifications, but I was curious if it's more voltage or current dependent. --- End quote --- Back EMF can be a huge problem and it's wise when using a PSU for powering such to take precautions to avoid subjecting the PSU outputs to back EMF. Regen motors also present the same issues and even reverse voltage protection can be exceeded and output stages damaged. |
| br4n_d0n:
Both of you, thanks for letting me know. I was going to just start playing around with some small ones without very much knowledge and it seems like that could've been damaging. |
| james_s:
You'll probably be fine, I played with electromagnets frequently when I was a kid and I never hurt anything although I did get a few shocks while leaning the principal behind a boost converter in the process. The large spike occurs when you open the circuit, which you'd normally do by disconnecting the wire that goes to the power supply and then the spike can't get to the power supply anyway. The strength of the magnetic field depends on the number of turns and the current through the turns. The more turns you have, the more voltage you will need to get the current up. |
| Fungus:
--- Quote from: br4n_d0n on May 10, 2023, 03:36:22 am ---No one has touched on the electromagnet part --- End quote --- It also won't care about noise from a switching supply. --- Quote from: bdunham7 on May 10, 2023, 03:42:47 am ---Small electromagnets are not particularly challenging and I think you'd typically use a CC (current regulated) supply. --- End quote --- Yep. You control the magnet strength by controlling the current. A CC supply will help you do that and not overheat the wires. :) The power supply you need for this will depend on how many amps you want. A lot of amps quickly becomes expensive. :popcorn: |
| mawyatt:
--- Quote from: tautech on May 10, 2023, 04:18:57 am --- --- Quote from: br4n_d0n on May 10, 2023, 03:36:22 am ---No one has touched on the electromagnet part; it will probably be dependent on its specifications, but I was curious if it's more voltage or current dependent. --- End quote --- Back EMF can be a huge problem and it's wise when using a PSU for powering such to take precautions to avoid subjecting the PSU outputs to back EMF. Regen motors also present the same issues and even reverse voltage protection can be exceeded and output stages damaged. --- End quote --- So true, and one MUST pay attention to such or likely fry the PSU!! Relays are basically solenoids electromagnetically, and should always utilize a current recovery diode to give the interrupted current a nice place to go as it decays, Ldi/dt can and will wreak havoc with things!! We are working with a controller for a high pressure DC motor that requires ~50 amps, so you can bet we are paying attention to back EMF as this can send the PS (and maybe yourself) to the grave if not properly attend too :o Best, |
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