Relay question

[Mike Stein]

Can you use a double pole button, use one pole to switch the relay and the 
other to control the current through the contacts?

I.e. every time you push the button the direction reverses but the lift is 
only energized as long as you hold the button in.

m

----- Original Message ----- 
From: "Jim Brain" <brain at jbrain.com>
To: <General at classiccmp.org>; "Discussion at classiccmp.org:On-Topic and 
Off-Topic Posts" <cctalk at classiccmp.org>
Sent: Friday, November 28, 2014 5:47 PM
Subject: Re: Relay question


> On 11/28/2014 4:40 PM, Mike Stein wrote:
>> Why not just do this the simple, usual way for an application like yours: 
>> a pair of nice, sealed, heavy duty industrial pushbuttons marked UP and 
>> DOWN, or even a single button with a nice heavy duty toggle switch 
>> similarly marked?
> For safety, the buttons on the lift (in the bucket), are air switches, 
> with the actual electrical portion down below.  I have not seen the unit, 
> but my father claims there is no more room for another air line in the 
> boom cable trace, so any more switches would have to be wireless, or 
> something else.
>
>
>>
>> Personally, I'd be a little leery pushing that button without knowing 
>> which way the lift is going to move when I do...
> I think that's why he wants the minimum complexity (no solid state, etc.). 
> I agree, there is some risk there, but he is currently happy with the 
> operation using an unsealed relay, I told him surely there existing a 
> sealed version of this thing.
>
> Yes, I could happily re-engineer it for him, but just like ill conceived 
> concepts on a vintage machine, I'm being asked to just make the current 
> setup work, not create a new setup.
>
> Jim