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  1. Minder

    Learning Kicad

    One other thing I do when starting the PCB is to set the various trace widths up that I think I may need and then it is very easy to select them when running traces. Larger for power etc. M.
  2. Minder

    VFD (Variable Frequency Driver) for 3-phase motors.

    Here they would just need to add one extra for the three phase, or none if It was 440v. That should all that should be required in most N.A. service supplies. Either way, it runs to the high 4 figures. M.
  3. Minder

    VFD (Variable Frequency Driver) for 3-phase motors.

    That's correct, but I think you may run into some resistance in N.A. when trying to convince the service Co to run 3ph into a residential panel. Some jurisdictions may vary. It will also cost Way more than a VFD. M.
  4. Minder

    VFD (Variable Frequency Driver) for 3-phase motors.

    In N.A. it is virtually impossible to get 3ph added, They did it for me once in the UK to supply a bank of storage heaters. As to using the Idler motor for motive power, the capacitors are tuned for optimum P.F. and for correct phase angle, so using the motor for mechanical power also, is...
  5. Minder

    VFD (Variable Frequency Driver) for 3-phase motors.

    Ah and therein lies the rub, as Will would say. Now you are going to place a mechanical load on the motor as well as one carrying an electrical load. Don't forget, this is not a synchronous 50hz/60hz generator. Just close to it. Max,. .
  6. Minder

    VFD (Variable Frequency Driver) for 3-phase motors.

    There is also two basic types of VFD, V/f and Vector control, depending on the application. https://www.machinedesign.com/motorsdrives/how-choose-right-control-method-vfds M.
  7. Minder

    VFD (Variable Frequency Driver) for 3-phase motors.

    The frequency/rpm is set or derived from the 3phases, the energy content of each phase is decided by the PWM switching rate. M.
  8. Minder

    VFD (Variable Frequency Driver) for 3-phase motors.

    PWM is typically used to vary the power content of a VFD 3 phase waveform. M.
  9. Minder

    VFD (Variable Frequency Driver) for 3-phase motors.

    My post was using the fixed freq 3ph versions, the VFD typically produces a variable frequency 3ph sine wave with PWM modulation of each cycle. The VFD linked to is one of the Huanyang Chinese versions and they typically lack any kind of decent support or manuals. Fortunately there are many that...
  10. Minder

    VFD (Variable Frequency Driver) for 3-phase motors.

    It helps to be larger than the motor it is feeding. BTW, this is a similar way that the electronic versions work, PhasePerfect etc, they take the 1ph and pass it directly through as two phases and produce the 3rd 120deg phase from the 240 1ph pair but electronically. M..
  11. Minder

    VFD (Variable Frequency Driver) for 3-phase motors.

    The one I show has only one, the 3ph motor, and yes, started by capacitor, the one with the 1ph pony motor does this start duty in place of the cap, but runs in a free wheel fashion after the start. M.
  12. Minder

    VFD (Variable Frequency Driver) for 3-phase motors.

    Here is a link to the one I used, in there there is a link to PDF that shows the design and tuning from one of the originators of the RPC, Fitch Willams. https://somanyhobbies.wordpress.com/2016/01/20/rotary-phase-converter/ M.
  13. Minder

    VFD (Variable Frequency Driver) for 3-phase motors.

    See this Utube for example of a Pony motor. The motor runs with the main motor but only under power at switch on to get the main motor up to speed. After this it can just free-wheel. The pony is a 1ph motor. I will see if I still have my DWG's. M.
  14. Minder

    VFD (Variable Frequency Driver) for 3-phase motors.

    The way a RPC works is it uses the standard 1ph 240v and uses a bank of capacitors to provide a phase shift to produce a 3rd conductor (3ph) If viewing it from a virtual neutral point of view, now you have 3 conductors that are 120deg out of phase with each other (WRT the virtual neutral). The...
  15. Minder

    VFD (Variable Frequency Driver) for 3-phase motors.

    The one I built a couple of decades ago had a P.B. start circuit using a capacitor, no pony motor. M.
  16. Minder

    VFD (Variable Frequency Driver) for 3-phase motors.

    Not strictly true, All the VFD's I have installed since the 80's have been on regular 3ph motors, two were on a machine I retro-fitted with motors from the 50's! If concerned, a 3ph choke/inductor can be fitted between VFD and motor. This helps both motor and VFD. M.
  17. Minder

    Learning Kicad

    It is not compulsory ;) But most cases advisable for most circuits.. Fortunately the one I forgot it on, was very low freq signals and minor circuitry. M.
  18. Minder

    Learning Kicad

    I usually place mounting holes in the corners. Also no ground plane? I use Greenshot for capturing JPG's. M.
  19. Minder

    Learning Kicad

    I have been using it since the older XP version, I tried the latest ver 5 and went back to a previous version as it seemed at that point there were some things to iron out. I agree there is a bit of a learning curve and some things do not appear obvious, but the older set of tutorials of Kicad...
  20. Minder

    Learning Kicad

    One gotcha that I fell foul of was after completing a board that I had configured a fill zone on. There is a command to make the zone temporarily invisible in order to make some final adjustments, but the zone limits still shows as an outline. So without refilling the zone, I sent the Gerbers...
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