Date:         Fri, 16 May 2014 10:03:37 -0600
Reply-To:     Gnarlodious <gnarlodious@GMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Gnarlodious <gnarlodious@GMAIL.COM>
Subject:      Re: Off topic Friday question on switches...
In-Reply-To:  <CAHTkEuJoxyY6gkxT+qcOUsY+7pQF+Qo5KkhS_E5s7c5shCKLug@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1

I realize this is somewhat abstract terminology. There is no such thing as 220
single phase. 220 is 2-phase, always. 110 is nominally single phase, and
220 is 2-phase.

120 is single phase, "120/230 single phase" is a nonsensical statement.

From the sound of your questions you may have wrongly wired a 2-phase
relay. Each phase must be switched through separate contacts to properly
suppress arcing when making contact.

I'm not an expert, and I don't know what broke in your switch, but I
suspect your motor is the type that starts up on a low voltage and when
spinning switches over to high voltage. This is normally called a wye-delta
hookup. If you have wired it wrongly to start up on high voltage it can be
bad for your neighborhood, your workshop, your switch and your motor.

In this scenario, the switch has a timer that spins up your motor, waits a
short amount of time, then switches to a higher voltage by adjusting which
phase hits the motor. A 3-phase motor would have 6 terminals running to the
switch, that is why the switch is so expensive. This wiring setup is used
on loaded (clutchless) machinery where the motor must slowly spin up some
mass using a lower voltage. Since an induction motor pulls infinite current
when not spinning, the wye-delta switch limits startup current until the
motor and load are spinning fast enough to protect your wiring and the
power company.

If you are chronically running induction motors wrongly wired you may
receive a friendly visit from the power company inquiring as to why your
workshop is degrading their "Power Factor". In order for the wires to
deliver quality power all three phases must be aligned properly to carry
equal voltage and current throughout their phase. Any disruption of this
relationship degrades the Power Factor.

In the third world people commonly take out the wye-delta switch and
substitute a plain switch, resulting in poor quality electricity and many
problems throughout the system.

-- Gnarlie



On Fri, May 16, 2014 at 8:59 AM, Don Hanson <dhanson928@gmail.com> wrote:

>   I have an induction-motored thickness planer, running on 220 single phase
> power...It came with a magnetic switch that has broken now 3 times and
> costs over $50 to replace...Hate that.   I found a normal power tool switch
> in my box, rated for a bigger motor than this tool I am working on
> now...but it is a "normal" heavy duty push button power tool switch, made
> for 120/230 single phase or 208/230/480 three phase...   This switch has
> four terminals on the back, two labeled "Load" and two labeled "Line"...
>
>    So the questions:
>
>   Can I try to wire up this less expensive (and already owned) switch to
> make the 220 induction motor work?  Right now I am using this tool, when I
> have to,  with my power panel breaker box as the only switch....very
> un-safe and not at all convenient.   I do need the use of this tool, but
> $50 a switch is now (in this tradesmen-unfriendly economic climate) not
> very feasible.
>
>   Second question:  If I decide to try this hack-job, wiring  for the wrong
> switch,  how should I connect the wires?   Do I take the black and white
> wires to the two terminals labeled "LIne" and continue on after the switch
> with the same colors out to the tool from the "Load" posts of the switch?
> Or do I just break one of the "Line" wires and use just one of the 'Line
> and Load" terminals, like on a house wiring switch?
>
>    I know this is sketchy stuff but it's really tough for a working man in
> the building trades now a days so I can't afford to do it right always when
> it comes to my own tools and expenses..I tried Goggling "induction motor
> wiring" etc etc...but I can't understand the wiring diagrams I get back...
>
>   Respond off the list if you think you may be able to advise, and thanks
>   Don Hanson
>