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Replacing limit switch with timer relay

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tonka6974

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I currently am looking to remove a motor control box from a commercial garage door from the door to off the door and a location on the wall this would allow easy access to control box when the door gets stuck in the up position. (currently have to get a man lift to work on control box when this happens)

Is it possible to replace the mechanical limit switches with a timer relay to control the motor limits by time instead of mechanical switches. The motor is a 2hp AC single phase. The timer could be adjusted to match the top and bottom opening and closing of the door.
 
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Is it possible to replace the mechanical limit switches with a timer relay to control the motor limits by time instead of mechanical switches. The motor is a 2hp AC single phase. The timer could be adjusted to match the top and bottom opening and closing of the door.
That's not advisable since the opening and closing speed of the door could vary some due to temperature, changes in friction, etc. It's best to retain the limit switches. Just run a wire to connect the switches to the control box.
 
Replacing limit switches

Thanks Carl,

but the limit switches are in the control box that needs to be re-located. I understand the differences that may occur. I don't want to make a new box just for the limit switches.

How are the digital garage door openers doing it? they have no mechanical limit switches.
 
but the limit switches are in the control box that needs to be re-located. I understand the differences that may occur. I don't want to make a new box just for the limit switches.

How are the digital garage door openers doing it? they have no mechanical limit switches.
I'm quite sure the new openers still have limit switches, either mechanical or electronic. Electronic limit switches could be done with an IR photo emitter and photo detector but mechanical is simpler.

You don't need to make a box for the limit switches. You can buy self contained ones that directly mount wherever you need them.
 
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Door won't go digital

Thanks again Carl,

The limit switches are located in the box, they run on a screw turn which is linked to the motor on the door. I don't want to run extra sensors or switches with cable. The point was to not have to replace parts that are "up in the air" a real safety issue.

I think the digital garage openers are using solid state programmable timers, but it looks like they might be using "Smart motors" as well as logic control. Looks like my door might be left in the "good old days".
 
You need an upper limit, a lower limit, over power limit and a obstacle detetor to keep it safe. I would not mess with it. Try and find out why it gets stuck in the up position and fix it.
 
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