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Need help with old Lightwood Drapery Control

wondering

New Member
I need help with an old drapery control motor. I'm staying at my sister's house while she is away and the drapery control has stopped working correctly. I'd like to fix the control before she returns to avoid being blamed for breaking her curtain opener. However, I know nothing about electronics or electric motors, so please answer in simple terms. There are no instruction booklets or installation instructions in the house or that I could find on the internet other than the one in the link below.

I could find very little about this motor on the internet; however, it is the same as the one from this ancient post on this forum:

and this other post:

The control is a Model SCA.

The motor has two cords that (I'm guessing) plug into two different wall outlets that are connected to a wall switch. There is also a three-way toggle type switch on the outside of the control box:
Position 1 (on the left): Power Cord #1, Motor Supply, 115 VAC, 1.0 AMP
Position 2 (center): Center OFF
Position 3 (on the right): Power Cord #2, Relay Control, 115 VAC 0.04 AMP

The curtain worked fine when my sister left, but one of my grandkids unplugged the controls when vacuuming and then messed with the switch to work the curtains, then the power went out, and now nobody remembers how the controls are supposed to be set. I have no idea how to get the settings working again (the motor pulls the drapes open and closed, but the motor doesn't stop when it should either when opening or closing the drapes). I tried tightening the drapery cord (to remove slack), which helped a little, but not enough.

Questions:
What position is the toggle switch supposed to be set at (1, 2, or 3) to work with the wall switch? Does it matter which position is used to open or close the curtains, Motor Supply or Relay Control? What is the difference between the Motor Supply and the Relay Control?

The wall switch is supposed to open the curtains when the switch is turned on and close the curtains when the switch is flipped off. How do I coordinate the wall switch with the drapery control? I assume the cords are plugged into two different outlets so that the wall switch either opens or closes the curtains independently based on the switch position? Does it matter which outlet the cords plug into?

Is there a way to adjust the motor to start and stop when the curtains reach fully opened and fully closed? The curtains don't seem to be opening and closing in sync with the motor anymore, plus the curtains don't seem to glide as smoothly along the track as before. Did I take up too much slack in the cord or is the cord in the wrong place relative to the correct open and close position to open and close and stop the motor when it should?

Thank you for any help and insight into my problem. With all your help, my hope is to have my sister's curtains working again with her none the wiser before she returns at the end of next week.

Thanks!
 

Diver300

Well-Known Member
Most Helpful Member
The motor power is supposed to be permanently supplied.

The curtains should go one way when the relay control is powered, and go back when the power is removed.

You could use a lamp or something to find which outlet is controlled by the wall switch, and then make sure that the relay control is plugged into that. If the motor power cord isn't turned on, you should still hear the relay click when it is turned on.

I don't think that the labels on the box, except for "off", apply to the switch, they apply to the power cords. The switch on the box is there to turn the system off, and to decide which direction the drapes should go in, so if the drapes should be open when the wall switch is on, or when the wall switch is off.

If the motor is not stopping when the drapes get to the end, that is most likely due to the switch not being operated by the black plastic switch actuator. See the other thread for photos). You can test that with the string removed. The motor should run all the time with the string removed and the black plastic switch actuator in the mid position. When you push the black plastic switch actuator to one side, but no the other, the motor should stop. When the motor is reversed by operating the wall switch, pushing the black plastic switch actuator the other way should stop the motor.

If that's all OK, it's just down to making sure that the string is tight enough to operate the switch. It is quite possible that the black plastic switch actuator is sticking, or that the pulleys aren't gripping the string as well as they did when the motor was new.
 

wondering

New Member
Thank you very much Diver 300 for making perfect logical sense out of (to me) a morass of variables. Using your suggestions, I was able to get the curtain going again. You were also right about the control box labels for the black power switch selecting the direction of opening and closing for syncing to the wall switch positions.

I'm still having problems with stoping the curtains though. The curtain cord runs inside a track in a continuous loop, down through the control box, and back up through the curtain track, with each cord end knotted to the same central, master carrier. The actuators appear to work okay, but the cord doesn't seem to work quite right? At the end of the cycle one cord feels too tight and the other feels too slack to me.

The curtains start okay, but then have trouble stopping. The cord appears to run through the motor evenly during most of cycle until the end. When the cord comes to the end of the cycle, opening or closing (usually opening), the motor has a hard time stopping (the curtains will be fully open, but the motor continues to run).

At the end of the cycle, the pulling action slows, the motor continues to run, and that's when you notice that one of the cords running through the control box has become either too tight or too slack, depending on whether the curtain is opening or closing. If you tug on the looser cord which is traveling upwards, the cord engages again (?) and completes the opening or closing cycle and the motor shuts itself off. I plan to tinker with the cord adjustment and actuators some more tomorrow.

Questions:
Would the old cord slipping through old pulleys cause the stopping problem or a problem with the actuators? The cord is old and definitely needs replacing (but not by me on this trip).

Would taking up the cord slack unevenly cause uneven pulling, hence the tight and loose cord situation? Would trying to reposition the cord in the pulleys resolve the problem?

Is there lubricant I could be using on the actuators if they are sticking or on other motor parts while I have the control box open?

At least the curtain works with the wall switch now which is an enormous relief! After having a wall heater and a bowl mishap, I was not looking forward to adding completely broken curtains to my list of bloopers...

Thanks again for all your thoughts and suggestions!
 

Diver300

Well-Known Member
Most Helpful Member
Questions:
Would the old cord slipping through old pulleys cause the stopping problem or a problem with the actuators? The cord is old and definitely needs replacing (but not by me on this trip).

Would taking up the cord slack unevenly cause uneven pulling, hence the tight and loose cord situation? Would trying to reposition the cord in the pulleys resolve the problem?

Is there lubricant I could be using on the actuators if they are sticking or on other motor parts while I have the control box open?
The cord slipping on the pulleys would definitely make thing worse.

It would probably be a good idea to get new tyres for the pulleys as well as a new cord when it's replaced.

When the motor stops there has to be significantly more tension in one cord than the other, enough to keep the switch actuator pulled to one side. I don't think that taking up the cord slack unevenly would make any difference, unless it ends up with a more or less worn part of the cord on the pulleys at one or other end of the travel.

The switch actuator should move as freely as possible, with just the spring pressure centreing it. It might help to lubricate it, but I can't see if there are places where it slides on the metal plate. I would use clean car engine oil. However, you have to keep oil off the cord and pulleys.

There will be gears and bearings in the motor assembly, but the motor seems to have enough power so that's not the problem at the moment.

I would hope that a modern opener would:-
1) Have a timer to stop the motor if it runs for too long.
2) Not have to leave a relay powered the whole time that the drapes are open (or closed, depending on the swtich)
3) Be able to turn off the motor and allow it to stop before reversing if the control is changed mid-run
4) Have better ways to detect the end of travel.
 

wondering

New Member
I'm sure the whole thing needs replacing with a better version of itself, but, it's not mine, I come from a disappearing world of fix and repair before replacing, and I'm loathe to leave my sister with a broken household item that worked fine before she left. I've been concentrating on the control box because I can reach it—an enthusiastic four-year-old grandchild, while helping me in the kitchen, dropped a large bowl on my foot simultaneously breaking the bowl and my foot which has made reaching the overhead curtain mechanism or any notion of replacing the cord, unfeasible these past two weeks.

The motor is probably 40 years old and still going strong; however, the company ceased business long ago, and as you suggested, newer and better mechanisms have been developed. While replacing the cord is doable, I wouldn't know where to begin to find replacement pulley tires that fit.

More questions if you have the patience:
What triggers the actuator to move at the end of the cycle? There doesn't seem to be any timer that I can see. Is the actuator triggered by the amount of resistance the motor encounters pulling on the cord so that the more resistance on the cord, the sooner the actuator moves and shuts off the motor? Or what?

Does making the cord tighter help to stop the control or does making the old cord tighter just encourage the cord to slide on the pulleys making it harder for the motor to detect when to stop?

A blog post suggested that using slightly thicker cord than normal could compensate for worn pulley tires since the pulley tires aren't available. Would that work or overtax the motor?

I appreciate your clear responses to my admittedly basic and uneducated questions—I'm clearly out of my depth here and nearing the limit of what I can do to fix things.

Thank you again.
 
Last edited:

Diver300

Well-Known Member
Most Helpful Member
What triggers the actuator to move at the end of the cycle? There doesn't seem to be any timer that I can see. Is the actuator triggered by the amount of resistance the motor encounters pulling on the cord so that the more resistance on the cord, the sooner the actuator moves and shuts off the motor? Or what?
There is no timer. The tension in the cord is a force directly along the cord. Anywhere that the cord changes direction, there is a force put onto whatever makes it change direction. In this case it's the switch actuator.

As there are two cords, if the tension is the same in both, there is no net force on the actuator. Just moving the drapes shouldn't take a lot of force, so the tensions are similar.

When the drapes hit the end, there is suddenly a lot more force pulling the drape, and the other side will go slack. That makes the forces uneven on the switch actuator, so it moves.
Does making the cord tighter help to stop the control or does making the old cord tighter just encourage the cord to slide on the pulleys making it harder for the motor to detect when to stop?
Making the cord tighter increases the friction between the cord and the motor, so it reduces the tendency to slip, which should make it easier to detect when to stop. However, having a tighter cord will also increase the friction as the cord passes over the switch actuator.
A blog post suggested that using slightly thicker cord than normal could compensate for worn pulley tires since the pulley tires aren't available. Would that work or overtax the motor?
Some of the friction comes from the cord being trapped between the motor wheel and the two idler wheels. If the tyres are worn, making the cord thicker seems like a good idea.

It won't overload the motor unless the cord were so thick that the tyres were being compressed a lot. If the motor runs freely with the cord in place but no tension on it, then the cord isn't too thick.
 

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