Time clock

[tbakelis]

Hello All,

I have a customer that has two sets of loads that he wants controlled (70 amps each). But because of the load amount, he can only run one set at a time and they cannot overlap. So I have to make sure when the one load turns off... the other set turns on after. My current plan is to set up 2 contactors to carry the individual loads and have a timer control the contactors. I was thinking of using an intermatic ET1715C (STDT) to operate them but not sure if it will work or if there is another (or better) way. I've set up basic timers to control contactors but have never been asked that two sets can't overlap. My initial though was two separate timers set to different times... but if someone messes with one... it could overlap with the other. That's why I thought that if there is one timer that can do both, that would be the way to go.

Any suggestions?

Thanks!

 

[mopowr steve]

Why not get a normally closed contact mounted to contactor 1 to lockout the 2nd contactor when timer is "on" energizing contactor 1. This would make a simple flip/flop based on timer. Timed power to contactor 1coil and constant power to feed NC contact-to contactor 2 coil. Now if the 2 contractors are to run independent times with no possibility of being "on" at the same time a little more is needed.

 

[eric9822]

Hello All,

I have a customer that has two sets of loads that he wants controlled (70 amps each). But because of the load amount, he can only run one set at a time and they cannot overlap. So I have to make sure when the one load turns off... the other set turns on after. My current plan is to set up 2 contactors to carry the individual loads and have a timer control the contactors. I was thinking of using an intermatic ET1715C (STDT) to operate them but not sure if it will work or if there is another (or better) way. I've set up basic timers to control contactors but have never been asked that two sets can't overlap. My initial though was two separate timers set to different times... but if someone messes with one... it could overlap with the other. That's why I thought that if there is one timer that can do both, that would be the way to go.

Any suggestions?

Thanks!

What exactly are you trying to do and what are the loads? Trying to alternate continuosly? Both off for extended periods of time? For the price of that intermatic timer I would be inclined to use a programmable relay instead. Something like this http://ab.rockwellautomation.com/Programmable-Controllers/Micro820 There are cheaper options also available. I would definitely run the control wiring for load #1 through a set of aux contacts on load #2's contactor(s) and vice versa. That would make sure both can't run at the same time.