Mechanically held contactors

Status
Not open for further replies.
J

Jeff80

Member
Its been a long time and I need help with mechanically held contactors. I know how they work if i use a momentary switch but with a regular time clock is where i am confused.

Do I always need a control relay? Does anyone have a good schematic with a time clock? Where can I get a good refresher?

This job is not the place I would want to test my guessing skills.
 
You can buy better time clocks with a pulsed output, or rig up a small time delay relay to close for .___ sec if you are stuck with a low end time clock. I have used both. The small tdr is easy and simple to replace if it fails. The time clock is expensive and almost requires 5 hours of CEU to program the first & each subsequent reprograming.
 
I've used a regular time clock wired to control a ice cube relay and then used the NO contact to latch the lighting contactor and the NC to unlatch.
 
ptonsparky said:
The time clock is expensive and almost requires 5 hours of CEU to program the first & each subsequent reprograming.
Click to expand...

Glad you said that, I had some trouble trying to offset the on time of an electronic astronomical clock. It took at least 90 mins trial and error with the manual.:roll:
 
If you're using an ASCO 917 or other type of mechanically held contactor any old time clock will work if set up for 2-wire control. The advantage of a momentary time clock is that you can install any number of momentary override switches in parallel with the time clock to turn the contactor on and off. This will not work if the time clock has a maintained contact.
 
Mechanically contactors need a NO NC controller you do not need to pulse them there are clearing contacts on the contactor to disconnect power as they open close.
 
brian john said:
Mechanically contactors need a NO NC controller you do not need to pulse them there are clearing contacts on the contactor to disconnect power as they open close.
Click to expand...

I agree but this takes away any possibility of multiple control points.

That may be acceptable or not depending on the customers wishes. :smile:
 
Status
Not open for further replies.
Top