Recent content by capthook

Hi Berkman - thanks for the reply. Don't know why you moved this... it's not a homework question... The equations of input vs. flux is not the issue, rather the relative performance of different core permeabilities. A higher permeability core in a motor application will perform better -...

A magnet is attached (or over a small airgap) to the end of an electromagnet (EM) with a steel core, then the EM is pulsed with just enough juice to get the magnet to drop off. (just negating the attraction) Which will require less energy input to get it to drop off? 1) a high permeability...

Hi Phrak - thanks for the reply! The problem is how to source a premimum material in small quantities, that is fully annealed and doesn't totally break the bank... Carpenter Steel offers some great (expensive) stuff and good info. This is a great read on core materials...

I'm trying to get feedback on electromagnet design and specifically sourcing premium core material for a pulse coil electromagnet. I have seen this question asked a few times on this forum, but doesn't appear to have really been answered. What is THE BEST core material and where to source...

This thread a few down may help: https://www.physicsforums.com/showthread.php?t=227148 I have decide to purchase this chip from LT as it an IC with all the components pre-assembled over a standard buck-converter. The exact model is because I require a very LOW power consumption. You are...

If you replace them with neos of equal gauss rating, rather than size - the magnets would be smaller. So yes - less air resistance, as well as weight, could result in an increase in efficiency. The output wouldn't increase if running at the same RPMs as before - but the input might decrease.

It depends... A stronger magnet will of course create a stronger flux, but it will create additional drag due to Lentz law and "cogging". As such - the air gap will have to be increased to keep things "equal", or power increased - else the torque and RPM's will decrease, resulting in lower...

Thank you for your reply! I'm glad to have validation for the process I was considering. I have decided to go with one of the LT chip models. FYI: Anyone that needs a SPICE program - LT offers a free/excellent one @: http://www.linear.com/designtools/software/switchercad.jsp CH

Hello all! Circuit to limit power draw from capacitor? I want to limit my 100,000 uF 35 V capacitor that is charged (via schottky full-wave bridge) to between 4V to 16 V from dumping it's charge all at once. I would like the capacitor to provide 300 mW to the load (10 ohm resistance)...

Thanks for the reply Integral! Some further details/parameters: I'm trying to maximize Amp-Turns(AT) while limiting current to under 1A @ 1.5V and under .5W consumption. ~200 AT should suffice. Coil #2: #22 AWG, 160 turns x .9A = 144 AT (.54 watts) Coil #4: #30 AWG, 1200 turns x...

Ahhh - thanks so much for the reply! I was banging my head! Thanks a ton! :cool: I guess Ohm's law should have an asterisk stating circuit voltage for guys like me! (rather than battery voltage measured before hooking it up!) And I guess I need to add battery resistance to my coil...

I'm trying to optimize pulse coils and determine power consumption. According to Ohm's law: P = V2/R where P=power / V=voltage / R=resistance Why isn't Ohm's law providing the same results as actual meter testing?? Testing coils with 1 "C" battery: 1.5 volts #1) 2.3 ohm coil...