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  1. Minder

    120 AC to 120 DC

    What I have done in the past for larger motors, is pick up one of the smaller low power KB SCR drives and removed the 3 rectifiers and 2 SCR's and mounted higher current versions off board on a larger heatsink. The KB has a shut down input for reversing so that the drive comes up in acceleration...
  2. Minder

    120 AC to 120 DC

    I assume this is a DC motor, if so you do not need a VFD as this produces variable AC frequency, a current common way of controlling a DC motor is either by a SCR bridge circuit that does not require a capacitor, The other is PWM which does require a suitable separate DC power supply, the SCR...
  3. Minder

    please can someone help with a project.

    Here is a full write up on polarity test. http://mgaguru.com/mgtech/ignition/ig104.htm M.
  4. Minder

    please can someone help with a project.

    Obtain one of the older ignition coils from an auto wrecker and look into 555 ic switching, there are also some examples out there using Google. M.
  5. Minder

    garage door opener

    That is a start/run capacitor and can be left in circuit as it is normally a oil/paper const. the start capacitor is a bi-polar electrolytic and must not be in circuit for more than a second or two. M.
  6. Minder

    help identifying part

    The Q designation are transistors, the 2 pin designated R are resistors C capacitors. M.
  7. Minder

    AC generator

    Is this for demonstration use or for a permanent usage/installation? Depends what resources you have. One very simple way would be to take copper pipe and fill with a insulation medium. This could be any fibre glass material such as two part resin or auto body filler. The centre could be drilled...
  8. Minder

    AC to DC welder

    Typically MIG welder etc have just a large choke in series with the torch conductor. M.
  9. Minder

    garage door opener

    The post in #11 shows the correct way to connect the windings, being identical windings either stator winding act as start and run winding just by alternatively placing the start capacitor in series with either winding with the other connected directly across the mains. I don't see it as a good...
  10. Minder

    detecting shaft rotation

    I have used the stated methods, the problem with the magnet, it can unbalance the motor rotor if the rpm is high. There is the retro-reflective means or the slotted opto, which entails a shutter mounted to the shaft, all these methods though will cause indication if using in a simple manner when...
  11. Minder

    dc motor questions

    A one cell LiPo may be a better choice, and at the lower voltage also rechargable. M.
  12. Minder

    Phoenix Contact 24vdc 40A power supply repair

    That is a SMPS type, so I would check the large semi conductors for a start, replace any bad looking caps. The transformer is a switch mode type and a shorted turn is a possibility. M.
  13. Minder

    PIC16f877A Blinking an LED

    Also in the OP you have used MOVLW 00h ;put 00000 MOVLW 85h ;move 00000 to TRISA All you did was clear W then move 85h to W , it did nothing to PORTA. M.
  14. Minder

    Safe sequencing of power

    A PLC would be good, also on a cheaper scale a SmartRelay could do it. M.
  15. Minder

    Confused with a contactor

    It appears to me as just a 12 row terminal strip. Continuity test would confirm it. M.
  16. Minder

    Confused with a contactor

    The wiring is a bit of a rats nest, you would need to reverse engineer it and post it for any decent help. Most of the wires are numbered which should help. http://static.schneider-electric.us/docs/Machine%20Control/0140CT9201.pdf M.
  17. Minder

    Confused with a contactor

    I get message saying not authorized to view attachments for some reason?? M.
  18. Minder

    Alternative for 8 2N3904 transistors in a single chip?

    The resistor arrays exist in dip or sip packages. m.
  19. Minder

    Simple question

    Simplest is 5v zener, resistor and cap, alot depends on the application as to method. M..
  20. Minder

    How to wire a contactor

    Not sure if it is possible with this particular contactor but many makes give the option of swapping the coil out for one of your choice. Keep in mind there is a difference between 24vac and 24dc coils and they have to be powered accordingly. M.
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