Tuesday, April 5, 2011

Stop! Limits!

We all have our stop limits. Having them adjusted properly is crucial to having a nice day. Now that other issues have been resolved and hopefully no other unexpected situations arise, we can proceed to adjusting ours down at the greenhouse skylights.

First we have to plug in the control box, which is an electric switch gizmo that allows the adjuster (me) to operate the tube motor that drives the rack & pinion contraption that opens and closes the skylights while observing the skylights in action and making the appropriate adjustments to the stop limit settings on the tube motor. The motors operate on 220 voltage, so it is necessary to tap into a nearby electrical subpanel to borrow some voltage. The photo below shows the black and white wires feeding the control box being tied into a double pole 30 amp breaker.

From there the current travels through a couple of extension cords to the box itself...

...which is connected in turn to the wires that feed the motor.

The 3-way toggle operates the motor in both directions, with "stop" being the middle toggle position. On the motor housing are the limit settings:

Begin by turning the setting screw to 'minimize', i.e. in the direction of the minus sign, so that you know you are starting from a place of maximum "stop limit".

Then, toggling with the control box switch up or

down, adjustments are made to bring the skylights to the appropriate place of rest, either open or closed.

When satisfied with the adjustments, I disconnect

the control box and reconect the motor to the

permanent wiring and return control to the automatic settings of the command computer.

Like all stop limits, these will have to be revisited occasionally and readjusted. Calling these things automatic is misleading. It's all manual in the real world. Language and reality have their stop limits too.

1 comment:

Jeannette said...

Oh...of course, the greenhouse. When you said you were writing about stop limits I thought you might be rendering a political opinion. This is a great tutorial...a manual. May your favorite plants thank you with healthy leaves and beautiful flowers.