[TowerTalk] TowerTalk Digest, Vol 151, Issue 6

[K2CB]

Joe,

Good point on the two switches wired in series being an issue once the tower reaches one of the limit points. In over thinking things, that fact slipped my mind. 

While the use of a 4PDT switch to include the switching of the hot lead would not be a bad idea safety wise, it still would not solve the issue if the neutral contacts shorted during actual operation, as in my case. The overall switch would still be in the on position while moving the tower. 

At least the motor would not buzz when the switch is returned to the off position if one set of contacts failed. But then again, that could be a bad thing, because then you would not know if there it was a failure with one of the other pole's contact set. 

I guess the best solution is just to do periodic testing, and hope it does not fail in the wrong circumstance!

Eric
K2CB 




> 
>> Looking over the wiring diagram for the control box after the fact,
>> I am questioning why UST did not just simply wire the two limit
>> switches in series, then just use the UP/DOWN toggle switch to break
>> the connection between the series-wired limit switches and the motor.
> 
> With the limit switches in series you would not be able to move the
> tower off either limit.
> 
> It would be better to use a 4PDT center off to switch hot/neutral or
> a using separate switches - one to control direction the other to
> switch power.  The problem with the two switch version is the need
> to remember to stop motion before reversing direction.
> 
> 73,
> 
>   ... Joe, W4TV
> 
> 
>> On 2015-07-02 12:34 AM, k2cb at comcast.net wrote:
>> I recently had an interesting issue with my HDX-589MDPL tower.  I am
>> posting my experience, hoping it saves someone from a potentially
>> catastrophic event. ********