[chbot] VFD with Chocolate fish.

[Mark Atherton]

Essential items to "feeling brave" include
- Rubber Gloves
- Fire Extinguisher
- Change of underwear
... But I am sure you know that, or at least Volker does.

I do tend to hide under the work bench when applying power after making 
the changes I suggested.

Ear defenders are sometimes useful also. What can possibly go wrong ?? :)

Seriously for one moment, check that the VSD ground bonding circuit is 
intact, and not only goes by a Big Green/Yellow Wire into the plug, but 
that the ground connector of the associated socket has a very low 
resistance to a the building's ground bonding stake.

-Mark



On 30/06/2021 7:28 PM, Richard Jones wrote:
> This document explains the different voltages to expect between single 
> phase vs 3 phase connected rectifiers and explains why you may find no 
> neutral connection in a 3 phase rectifier.
> 
> https://www.electronics-tutorials.ws/power/three-phase-rectification.html
> 
> So as Mark inferred, connecting a single phase supply to 2 phases in 
> lieu of the 3 phase connections should be safe enough once you verify 
> the capacitor ratings and you are feeling brave.
> 
> However, will the motor being driven cope with the reduced supply voltage?
> 
> Cheers
> 
> Richard
> 
> On Wed, Jun 30, 2021 at 7:13 PM Mark Atherton <markaren1 at xtra.co.nz 
> <mailto:markaren1 at xtra.co.nz>> wrote:
> 
>     Wallace,
> 
>     Have you checked continuity between mains in and the bridge rectifier
>     using a meter, or just by inspection ?
> 
>     Not sure of the rating of the unit you have purchased, but I might also
>     expect some kind of power-factor correction before the main reservoir
>     caps. Are you 100% sure that the input terminals don't dive off around
>     somewhere and then back to the caps ?
> 
>     -Mark
> 
> 
>     On 30/06/2021 7:08 PM, Mark Atherton wrote:
>      > Sounds like the factory modified the product (wrongly) then
>     shipped it
>      > without testing it.
>      >
>      > Three phase inputs (L1, L2, L3) should go the the bridge
>     rectifier via
>      > R, S & T.
>      >
>      > I have a couple of 3 ph VSDs that don't trip with under voltage
>     if you
>      > use single phase, and attach phase to L1, and neutral to L2.
>      >
>      > Before you go any further, what is the voltage rating of the
>     reservoir
>      > cap(s) directly after the bridge rectifier ?
>      >
>      > I would expect at least 385V caps for the 240V model and 620V
>     caps (can
>      > you get these ?) for the 3 ph 415V variant.
>      >
>      > -mark
>      >
>      >
>      >
>      > On 30/06/2021 6:04 PM, Marshland Engineering wrote:
>      >> I'm stumped with a VFD from Aliexpress. Here it is
>      >> https://www.aliexpress.com/item/1005002038502819.htm
>      >>
>      >> Nothing turn on with power. As a true engineer, off came the cover.
>      >> Now I'm
>      >> either blind, missing something  completely or its a faulty design.
>      >>
>      >> It has a 3 phase rectifier in it, + and - go to the HV caps. One
>     of the 3
>      >> phase input leads is cut off. Looks like a factory job. The
>     other 2 input
>      >> leads are soldered together on the PCB and go to the input live
>      >> terminal. I
>      >> cannot find any connection on the PCB from the neutral terminal.
>      >> Stumped. Now
>      >> I did get a complete new PCB when I discovered they sent me a
>     240V out
>      >> instead
>      >> of 380V one . It is exactly the same.
>      >>
>      >> Anyone got a few minutes free tomorrow ? I come loaded with
>     chocolate
>      >> fish or
>      >> similar.
>      >>
>      >> Cheers Wallace
>      >> 03 3237449
> 
> 
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