Re: Potential relay strangeness

Please!!!!
Be Careful and double check my observations before trying any of this:
I'm a EE, but not a certified house electrician, These are my
views on house wiring so far and I welcome corrections:


With that said:

House wiring basics I've observed:
Both legs of the 220v (110v+110v) line
are returned to the neutral(white). So your 110 outlets are either
(white(neutral) and black(hot)), or (white(neutral) and red(hot)).
The red color wire is usually only seen in your main breaker box.
(White is always neutral and black is connected to
either red or black)

Your electical loads are either wired on
one side or the other for a fairly even balance of circuits with
respect to both phases.

Thats what they mean by outlets being on
one phase or the other in your house.


This is what I think is the the problem:
If you have the relay
attached across the 2 220 'hot' legs(black and red)its
always going to be energized and keep to start cap out of circuit.
Probably a surge/dip is making the voltage to dip enough that the
start cap gets engaged momentarily to the circuit. You need to
reference to the neutral (white) leg or use the
transformer tap. The heavy white neutral leg will need a
connection from in your circuit breaker box. It is
connected to the 110v ground only at the box. DO NOT
use a 110v ground wire as
the connection point for Neutral!!!!. In house wiring the
ground and the neutral are the same potential, but ONLY
connected at the box. Always think of them as separate
circuits. The ground is used to safely ground your equipment.

The safest way is to use the transformer. I found a tranformer
rated at a couple of amps on the secondary(12+12vac), and
110 or 220 on the primary. For the 220 connection, the
transformer has 2 primary winding the can be connected in series.
This middle point is where the potential relay is referenced.
The potential relay mentioned in the Carlson article is
calibrated for ~190 activation.

( That explains why it seems always open across the 2 'hot' legs)

-Lee

--- In CAD_CAM_EDM_DRO@egroups.com, Drew Rogge <drew@p...> wrote:
> Lee,
>
> Actually I'm referencing the potential relay off of one of the
> hot legs of the single phase input as shown in the second drawing
> down at:
>
> http://gwm4-3phase.com/static1.htm
>
> I thought about using the dual-primary but didn't know what xformer
> to use. What are you using? I think the problem may that the voltage
> difference coming through from somewhere to keep the potential relay
> energized although that doesn't explain why it works when the input
> switch to the converter is used.
>
> Now, I'll be the first to admit that I really don't know what I'm
> doing so here's a LAG (lousy ASCII graphics) schematic of the way I
> have things wired for now.
>
> o--------------o-|\|--o-----o-------o------ T3
> | \ | |
> | /__ PR | |
> | /_ | |
> --- | --- |
> Cs _ o Cr1 _ |
> /|\ | /|\ |
> | | | |
> L2 ---------------o------------------ ) ------o------- ) ---- T2
> | |
> | ---
> | Cr2 _
> | /|\
> | |
> L1 ----------------------------------o----------------o------ T1
>
> Cs is the start cap, Cr[12] are the run caps. PR is the potential
> relay.
>
> To be honest, I'm suprised that the thing works as well as it does.
> Anyone have any ideas why I can switch L1/L2 and have things work
> and have things not work when I switch T1/T2/T3?
>
> Drew
>
> On Oct 2, 8:04pm, Lee Studley wrote:
> > Subject: [CAD_CAM_EDM_DRO] Potential relay strangeness
> >
> > I copied this to a new thread in hopes it
> > might be of use to others:
> >
> >
> > Drew,
> > Those are the 2 documents I'm going off of also.
> >
> > Thats an interesting point on the motor switch.
> > If the 3rd 'derived' phase is disconnected, the
> > potential relay (normally closed) should be closed
> > automatically(connecting the start cap) until the the 3rd leg is
> > reconnected and up to speed/potential. Are you sure you dont have
> > the common coil/contact swapped somehow? In the diagram for the
> > rotary convertor it is reversed from that of the static, since a
> > 'slave' contactor is being used. Also, where are you referencing
> > the other side of the coil for neutral? I went with the
dual-primary
> > tranformer centertap. Then I can have an aux low voltage supply
> > for an RPM meter and monitor etc.
> >
> > Let me know what you find,
> >
> > -Lee
> >
> >-- End of excerpt from Lee Studley
>
>
>
> --
> Drew Rogge
> drew@p...