Re: SPDT 4 wire & 2 wire circuits

[PFB <TIGHTWAD@xxxxxxxx>]

Steven wrote:
> Thank you, Now I understand.
> "Mike Sokoly" <secure15@xxxxxxxxxxxxx> wrote in message
> news:t2ccf.11179$rc7.9410@xxxxxxxxxxx
>
>>Electrical Parlance for  "Single Pole- Double Throw" as in a switch.
>>
>>
>>Steven wrote:
>>
>>>Hi,
>>> What does "SPDT" refer to? Sentrol makes a magnet switch with no "SPDT"
>>>I can't figure it out.  Steven
>
>
>
Years past these were also referred to as Type "C" contacts used
especially in Direct Wire systems to cause a "Double Drop" (open and
short to ground) when the device was tripped. This needed a 4 wire loop
or a correctly wired 2 wire circuit with end of line resistors installed.