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  • Users: Lakey
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  1. Lakey

    Relay Power Dissipation Reduction

    Suggestion: Adjust the program so that full voltage (14V!) is applied for enough time to allow the relay to pull-in fully, then apply PWM at > 20% coil volts. Regards,
  2. Lakey

    Aluminium Busbar joints & supports

    For comparison, you could evaluate the voltage drop across each type joint at a selected load (constant current). The clamping force should be sufficient to handle the peak current and other environmental issues, such as the Amb. Temp. and shock & vibration. Test is best. Regards,
  3. Lakey

    Magnetic separator

    You could consider an electromagnetic solution whereby you could adjust the strength of the field. For comparison purposes you could measure the pull or separating force that was required to separate a piece of iron/steel from your drum. A simple force gauge or spring gauge that could hold the...
  4. Lakey

    DC Motor arcing across relay contacts

    Hello, I’ve always understood that SSR’s are not considered fail safe for this type of application. Perhaps someone can enlighten me if I have been misinformed. Is this a series wound motor(kW)? What is the nominal running current, and expected ‘in-rush/start-up current? How inductive is it...
  5. Lakey

    DC Contactor magnets destroyed.

    Alternatively, you could assess some of the Albright range of contactors – maybe one the SW80B series. http://www.albrightinternational.com/lang/en/index.html Regards,
  6. Lakey

    Quick release mechanism electrically operated?

    1. I had provided those values from experience. You can find all the formulae you need on Wikipedia or , for example, www.magnetapplications.com The formulae will get you so far, but there is no substitute for the actual tests that must be performed. 2. I’d guesstimate that an ½” Dia X ¼”...
  7. Lakey

    Quick release mechanism electrically operated?

    Hi Ktysai, Yes, that’s correct. A Neo. magnet (3/4” Dia. x 3/16” thick) should provide a hold in excess of 90N. A 1000 ampere-turns coil should destabilise the flux sufficiently for the release of the spring mechanism. The actual size of your magnet and coil will depend upon your application...
  8. Lakey

    Quick release mechanism electrically operated?

    Suggestion: A permanent magnet (such as a neodymium) could be utilised to keep your spring compressed. If a coil was wound around the magnet, the magnet could be momentarily demagnetised when current flows through your coil - thus releasing your spring. Regards,
  9. Lakey

    Inrush Current Simulation

    This may be a bit late in the day, but you could try using a series capacitor to simulate the instantaneous current of the pump-motor (DC series wound). The amplitude of the inrush can be controlled with a resistor, i.e. pre-charged capacitor. This may save a few bucks. Regards,
  10. Lakey

    Magnetic blowout on relay contacts

    Question for Sreid: how does a ‘metallic arc’ differ from an ‘arc’? It is my understanding that: [a] ‘Blowouts’ are generally used to break the arc upon contact opening. [b] Basically, the nature of the arc will be determined by the circuit, contacts & atmospheric conditions. [c] When...
  11. Lakey

    Saturation of a Magnetic Frame

    Thanks Ed. That's what I was thinking. So, for this method, I have one vote for and one vote against. Kind regards,
  12. Lakey

    Saturation of a Magnetic Frame

    Thanks Mike. I can confirm that I will be able to generate enough A-ts to saturate the frame. Also, to be clear, I should have mentioned that this is a DC solenoid. I was hoping the exp will also show me how much power is required to fully saturate the frame, and to define the point on the...
  13. Lakey

    Saturation of a Magnetic Frame

    Is it feasible to determine whether or not a magnetic frame is saturated by the following experiment? Device: A small solenoid, approx 1.5inch by 2.0inch. Method: The solenoid is secured in a non-magnetic fixture. The armature position is fixed half way along its stoke. [full stroke approx...
  14. Lakey

    Acronym for Resistor color code

    For the ROYGBIV bit, I was taught “Richard Of York Gave Battle In Vain” Regards,
  15. Lakey

    Electromagnet: lamination vs. solid core

    In my opinion, Isrealkk is spot on. A star for you mate. Regards,
  16. Lakey

    Amplitude of EMF/BEMF when a coil is de-energised

    Skogs, Excellent explanation – a star for you. At the nearest opportunity I will conduct an experiment where the switch opening times versus peak voltage can be monitored. Thanks & regards,
  17. Lakey

    Amplitude of EMF/BEMF when a coil is de-energised

    Good Morning, I’ve read somewhere that “ theoretically, the peak voltage that is generated when you disconnect a coil form its supply, without suppression of any kind, may be infinite”. If it is theoretical then, I guess, there must be a recognised formula that can be applied. I done the...
  18. Lakey

    Help with electromagnet flux/field calcs

    Hi, Thread 237-84957 may be of some assistance to you. Happy hunting. Regards,
  19. Lakey

    Temperature recording

    Hi Crunch, Try http://www.picotech.com/ You might find what your looking for. Best regards,
  20. Lakey

    Springs - Distempered or Detempered

    My personal view is that it is correct to say “de-tempered”, but I’ve had a conflicting opinion. Hence I want to check.

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